How does Bitcoin work? - Bitcoin

StableCoin

This subreddit is dedicated to inform and discuss the revolutionary cryptocurrency Stablecoin.
[link]

Cool explanation of the SHA-256 Algorithm and how it's used to mine Bitcoin

Cool explanation of the SHA-256 Algorithm and how it's used to mine Bitcoin submitted by Ditochi to videos [link] [comments]

How Bitcoin mining REALLY works - an in-depth technical explanation of the proof-of-work algorithm that makes Bitcoin the most secure currency in the world

How Bitcoin mining REALLY works - an in-depth technical explanation of the proof-of-work algorithm that makes Bitcoin the most secure currency in the world submitted by SimilarAdvantage to BitcoinAll [link] [comments]

Looking for a good explanation of the public key algorithm. /r/Bitcoin

Looking for a good explanation of the public key algorithm. /Bitcoin submitted by BitcoinAllBot to BitcoinAll [link] [comments]

Interactive explanation of Public-Key Encryption by RSA Algorithm (Bitcoin uses ECDSA instead of RSA)

submitted by f00000000 to CryptocurrencySA [link] [comments]

Why Bitcoin is a long shot: an algorithmic explanation

Boolean willBitcoinWork() { if !is_outlawed if is_convenient if is_safe if is_accepted_by_merchants if !is_over_regulated if !is_51_percent_takeover if !is_diluted_by_altcoins if !is_replaced_by_FED if is_scalable if !is_hacked if !is_created_by_NSA if !is_other_fatal_flaw return BITCOIN_SUCCESS else return BITCOIN_FAIL } 
That's a lot of nested IFs. In probabilistic terms, the outcome of these dependencies is expressed as not the sum, but the product of individual events. As an example, if we define each of these conditions as probability .5, the chances that Bitcoin will ultimately work are ony 1 in 212 or 1 in 4096.
submitted by wonderkindel to Bitcoin [link] [comments]

Use weaker hash from strong hash to reduce size ?

Hello,
I was wondering if it would make sense to use a weaker hash algorithm (e.g. MD5 or SHA-1) on a hash generated by a stronger one (e.g. SHA-2, SHA-3) to reduce the storing size of the hash.Every keys will be hashed 2 times (e.g key -> SHA-2 -> MD5).
I was reading The bitcoin block size limit controversy (link) and was wondering if reducing the hash of Previous Block and Merkel Root could reduce the size of a block.
What are the consequences of doing that?

Edit: thank you for all your explanations!
submitted by LutinRose to crypto [link] [comments]

Mining algorithm differences between currencies

Apologies if this question has been asked before; I am looking for more technical resources than a simplification or easy explanation (not that anything's wrong with people looking for those kinds of explanations).
TL;DR: Why does Monero and several other newer digital currencies employ the CPU as the main compute element for mining, whereas e.g. Bitcoin started out in that way but migrated quickly to algorithms employing the GPU?
Is it the complexity of the problem? I know CPUs are much better suited to more classes of problems to solve; that's why we have CPUs with 4-32 cores that are incredibly multipurposely programmable and GPUs with thousands/tens of thousands of cores which are incredibly specialized. Or is it some other reason?
I'd love to dive into this subject very technically. I have > 25 years in IT (hardware including distributing computing before the word "cloud" meant anything other than a collection of water vapor hanging in the sky; software development from GW-BASIC and C to Perl/PHP to Java to .NET Core and beyond/in between; devops; etc.). I just haven't really studied the fundamentals of blockchain.
Again, apologies if this question has been asked. If there are technical resources out there, feel free to paste links; I don't want to waste anyone's time.
Thanks for any information!
submitted by FrontColonelShirt to Monero [link] [comments]

[ANN][ANDROID MINING][AIRDROP] NewEnglandcoin: Scrypt RandomSpike

New England
New England 6 States Songs: https://www.reddit.com/newengland/comments/er8wxd/new_england_6_states_songs/
NewEnglandcoin
Symbol: NENG
NewEnglandcoin is a clone of Bitcoin using scrypt as a proof-of-work algorithm with enhanced features to protect against 51% attack and decentralize on mining to allow diversified mining rigs across CPUs, GPUs, ASICs and Android phones.
Mining Algorithm: Scrypt with RandomSpike. RandomSpike is 3rd generation of Dynamic Difficulty (DynDiff) algorithm on top of scrypt.
1 minute block targets base difficulty reset: every 1440 blocks subsidy halves in 2.1m blocks (~ 2 to 4 years) 84,000,000,000 total maximum NENG 20000 NENG per block Pre-mine: 1% - reserved for dev fund ICO: None RPCPort: 6376 Port: 6377
NewEnglandcoin has dogecoin like supply at 84 billion maximum NENG. This huge supply insures that NENG is suitable for retail transactions and daily use. The inflation schedule of NengEnglandcoin is actually identical to that of Litecoin. Bitcoin and Litecoin are already proven to be great long term store of value. The Litecoin-like NENG inflation schedule will make NewEnglandcoin ideal for long term investment appreciation as the supply is limited and capped at a fixed number
Bitcoin Fork - Suitable for Home Hobbyists
NewEnglandcoin core wallet continues to maintain version tag of "Satoshi v0.8.7.5" because NewEnglandcoin is very much an exact clone of bitcoin plus some mining feature changes with DynDiff algorithm. NewEnglandcoin is very suitable as lite version of bitcoin for educational purpose on desktop mining, full node running and bitcoin programming using bitcoin-json APIs.
The NewEnglandcoin (NENG) mining algorithm original upgrade ideas were mainly designed for decentralization of mining rigs on scrypt, which is same algo as litecoin/dogecoin. The way it is going now is that NENG is very suitable for bitcoin/litecoin/dogecoin hobbyists who can not , will not spend huge money to run noisy ASIC/GPU mining equipments, but still want to mine NENG at home with quiet simple CPU/GPU or with a cheap ASIC like FutureBit Moonlander 2 USB or Apollo pod on solo mining setup to obtain very decent profitable results. NENG allows bitcoin litecoin hobbyists to experience full node running, solo mining, CPU/GPU/ASIC for a fun experience at home at cheap cost without breaking bank on equipment or electricity.
MIT Free Course - 23 lectures about Bitcoin, Blockchain and Finance (Fall,2018)
https://www.youtube.com/playlist?list=PLUl4u3cNGP63UUkfL0onkxF6MYgVa04Fn
CPU Minable Coin Because of dynamic difficulty algorithm on top of scrypt, NewEnglandcoin is CPU Minable. Users can easily set up full node for mining at Home PC or Mac using our dedicated cheetah software.
Research on the first forked 50 blocks on v1.2.0 core confirmed that ASIC/GPU miners mined 66% of 50 blocks, CPU miners mined the remaining 34%.
NENG v1.4.0 release enabled CPU mining inside android phones.
Youtube Video Tutorial
How to CPU Mine NewEnglandcoin (NENG) in Windows 10 Part 1 https://www.youtube.com/watch?v=sdOoPvAjzlE How to CPU Mine NewEnglandcoin (NENG) in Windows 10 Part 2 https://www.youtube.com/watch?v=nHnRJvJRzZg
How to CPU Mine NewEnglandcoin (NENG) in macOS https://www.youtube.com/watch?v=Zj7NLMeNSOQ
Decentralization and Community Driven NewEnglandcoin is a decentralized coin just like bitcoin. There is no boss on NewEnglandcoin. Nobody nor the dev owns NENG.
We know a coin is worth nothing if there is no backing from community. Therefore, we as dev do not intend to make decision on this coin solely by ourselves. It is our expectation that NewEnglandcoin community will make majority of decisions on direction of this coin from now on. We as dev merely view our-self as coin creater and technical support of this coin while providing NENG a permanent home at ShorelineCrypto Exchange.
Twitter Airdrop
Follow NENG twitter and receive 100,000 NENG on Twitter Airdrop to up to 1000 winners
Graphic Redesign Bounty
Top one award: 90.9 million NENG Top 10 Winners: 500,000 NENG / person Event Timing: March 25, 2019 - Present Event Address: NewEnglandcoin DISCORD at: https://discord.gg/UPeBwgs
Please complete above Twitter Bounty requirement first. Then follow Below Steps to qualify for the Bounty: (1) Required: submit your own designed NENG logo picture in gif, png jpg or any other common graphic file format into DISCORD "bounty-submission" board (2) Optional: submit a second graphic for logo or any other marketing purposes into "bounty-submission" board. (3) Complete below form.
Please limit your submission to no more than two total. Delete any wrongly submitted or undesired graphics in the board. Contact DISCORD u/honglu69#5911 or u/krypton#6139 if you have any issues.
Twitter Airdrop/Graphic Redesign bounty sign up: https://goo.gl/forms/L0vcwmVi8c76cR7m1
Milestones
Roadmap
NENG v1.4.0 Android Mining, randomSpike Evaluation https://github.com/ShorelineCrypto/NewEnglandCoin/releases/download/NENG_2020_Q3_report/NENG_2020_Q3_report.pdf
RandomSpike - NENG core v1.3.0 Hardfork Upgrade Proposal https://github.com/ShorelineCrypto/NewEnglandCoin/releases/download/2020Q1_Report/Scrypt_RandomSpike_NENGv1.3.0_Hardfork_Proposal.pdf
NENG Security, Decentralization & Valuation
https://github.com/ShorelineCrypto/NewEnglandCoin/releases/download/2019Q2_report/NENG_Security_Decentralization_Value.pdf
Whitepaper v1.0 https://github.com/ShorelineCrypto/NewEnglandCoin/releases/download/whitepaper_v1.0/NENG_WhitePaper.pdf
DISCORD https://discord.gg/UPeBwgs
Explorer
http://www.findblocks.com/exploreNENG http://86.100.49.209/exploreNENG http://nengexplorer.mooo.com:3001/
Step by step guide on how to setup an explorer: https://github.com/ShorelineCrypto/nengexplorer
Github https://github.com/ShorelineCrypto/NewEnglandCoin
Wallet
Android with UserLand App (arm64/armhf), Chromebook (x64/arm64/armhf): https://github.com/ShorelineCrypto/NewEnglandCoin/releases/tag/v1.4.0.5
Linux Wallet (Ubuntu/Linux Mint, Debian/MX Linux, Arch/Manjaro, Fedora, openSUSE): https://github.com/ShorelineCrypto/NewEnglandCoin/releases/tag/v1.4.0.3
MacOS Wallet (10.11 El Capitan or higher): https://github.com/ShorelineCrypto/NewEnglandCoin/releases/tag/v1.4.0.2
Android with GNUroot on 32 bits old Phones (alpha release) wallet: https://github.com/ShorelineCrypto/NewEnglandCoin/releases/tag/v1.4.0
Windows wallet: https://github.com/ShorelineCrypto/NewEnglandCoin/releases/tag/v1.3.0.1
addnode ip address for the wallet to sync faster, frequently updated conf file: https://github.com/ShorelineCrypto/cheetah_cpumineblob/mastenewenglandcoin.conf-example
How to Sync Full Node Desktop Wallet https://www.reddit.com/NewEnglandCoin/comments/er6f0q/how_to_sync_full_node_desktop_wallet/
TWITTER https://twitter.com/newenglandcoin
REDDIT https://www.reddit.com/NewEnglandCoin/
Cheetah CPU Miner Software https://github.com/ShorelineCrypto/cheetah_cpuminer
Solo Mining with GPU or ASIC https://bitcointalk.org/index.php?topic=5027091.msg52187727#msg52187727
How to Run Two Full Node in Same Desktop PC https://bitcointalk.org/index.php?topic=5027091.msg53581449#msg53581449
ASIC/GPU Mining Pools Warning to Big ASIC Miners Due to DynDiff Algo on top of Scrypt, solo mining is recommended for ASIC/GPU miners. Further more, even for mining pools, small mining pool will generate better performance than big NENG mining pool because of new algo v1.2.x post hard fork.
The set up configuration of NENG for scrypt pool mining is same as a typical normal scrypt coin. In other word, DynDiff on Scrypt algo is backward compatible with Scrypt algo. Because ASIC/GPU miners rely on CPU miners for smooth blockchain movement, checkout bottom of "Latest News" section for A WARNING to All ASIC miners before you decide to dump big ASIC hash rate into NENG mining.
(1) Original DynDiff Warning: https://bitcointalk.org/index.php?topic=5027091.msg48324708#msg48324708 (2) New Warning on RandomSpike Spike difficulty (244k) introduced in RandomSpike served as roadblocks to instant mining and provide security against 51% attack risk. However, this spike difficulty like a roadblock that makes big ASIC mining less profitable. In case of spike block to be mined, the spike difficulty immediately serve as base difficulty, which will block GPU/ASIC miners effectively and leave CPU cheetah solo miners dominating mining almost 100% until next base difficulty reset.
FindBlocks http://findblocks.com/
CRpool http://crpool.xyz/
Cminors' Pool http://newenglandcoin.cminors-pool.com/
SPOOL https://spools.online/
Exchange
📷
https://shorelinecrypto.com/
Features: anonymous sign up and trading. No restriction or limit on deposit or withdraw.
The trading pairs available: NewEnglandcoin (NENG) / Dogecoin (DOGE)
Trading commission: A round trip trading will incur 0.10% trading fees in average. Fees are paid only on buyer side. buy fee: 0.2% / sell fee: 0% Deposit fees: free for all coins Withdraw fees: ZERO per withdraw. Mining fees are appointed by each coin blockchain. To cover the blockchain mining fees, there is minimum balance per coin per account: * Dogecoin 2 DOGE * NewEnglandcoin 1 NENG
Latest News Aug 30, 2020 - NENG v1.4.0.5 Released for Android/Chromebook Upgrade with armhf, better hardware support https://bitcointalk.org/index.php?topic=5027091.msg55098029#msg55098029
Aug 11, 2020 - NENG v1.4.0.4 Released for Android arm64 Upgrade / Chromebook Support https://bitcointalk.org/index.php?topic=5027091.msg54977437#msg54977437
Jul 30, 2020 - NENG v1.4.0.3 Released for Linux Wallet Upgrade with 8 Distros https://bitcointalk.org/index.php?topic=5027091.msg54898540#msg54898540
Jul 21, 2020 - NENG v1.4.0.2 Released for MacOS Upgrade with Catalina https://bitcointalk.org/index.php?topic=5027091.msg54839522#msg54839522
Jul 19, 2020 - NENG v1.4.0.1 Released for MacOS Wallet Upgrade https://bitcointalk.org/index.php?topic=5027091.msg54830333#msg54830333
Jul 15, 2020 - NENG v1.4.0 Released for Android Mining, Ubuntu 20.04 support https://bitcointalk.org/index.php?topic=5027091.msg54803639#msg54803639
Jul 11, 2020 - NENG v1.4.0 Android Mining, randomSpike Evaluation https://bitcointalk.org/index.php?topic=5027091.msg54777222#msg54777222
Jun 27, 2020 - Pre-Announce: NENG v1.4.0 Proposal for Mobile Miner Upgrade, Android Mining Start in July 2020 https://bitcointalk.org/index.php?topic=5027091.msg54694233#msg54694233
Jun 19, 2020 - Best Practice for Futurebit Moonlander2 USB ASIC on solo mining mode https://bitcointalk.org/index.php?topic=5027091.msg54645726#msg54645726
Mar 15, 2020 - Scrypt RandomSpike - NENG v1.3.0.1 Released for better wallet syncing https://bitcointalk.org/index.php?topic=5027091.msg54030923#msg54030923
Feb 23, 2020 - Scrypt RandomSpike - NENG Core v1.3.0 Relased, Hardfork on Mar 1 https://bitcointalk.org/index.php?topic=5027091.msg53900926#msg53900926
Feb 1, 2020 - Scrypt RandomSpike Proposal Published- NENG 1.3.0 Hardfork https://bitcointalk.org/index.php?topic=5027091.msg53735458#msg53735458
Jan 15, 2020 - NewEnglandcoin Dev Team Expanded with New Kickoff https://bitcointalk.org/index.php?topic=5027091.msg53617358#msg53617358
Jan 12, 2020 - Explanation of Base Diff Reset and Effect of Supply https://www.reddit.com/NewEnglandCoin/comments/envmo1/explanation_of_base_diff_reset_and_effect_of/
Dec 19, 2019 - Shoreline_tradingbot version 1.0 is released https://bitcointalk.org/index.php?topic=5121953.msg53391184#msg53391184
Sept 1, 2019 - NewEnglandcoin (NENG) is Selected as Shoreline Tradingbot First Supported Coin https://bitcointalk.org/index.php?topic=5027091.msg52331201#msg52331201
Aug 15, 2019 - Mining Update on Effect of Base Difficulty Reset, GPU vs ASIC https://bitcointalk.org/index.php?topic=5027091.msg52169572#msg52169572
Jul 7, 2019 - CPU Mining on macOS Mojave is supported under latest Cheetah_Cpuminer Release https://bitcointalk.org/index.php?topic=5027091.msg51745839#msg51745839
Jun 1, 2019 - NENG Fiat project is stopped by Square, Inc https://bitcointalk.org/index.php?topic=5027091.msg51312291#msg51312291
Apr 21, 2019 - NENG Fiat Project is Launched by ShorelineCrypto https://bitcointalk.org/index.php?topic=5027091.msg50714764#msg50714764
Apr 7, 2019 - Announcement of Fiat Project for all U.S. Residents & Mobile Miner Project Initiation https://bitcointalk.org/index.php?topic=5027091.msg50506585#msg50506585
Apr 1, 2019 - Disclosure on Large Buying on NENG at ShorelineCrypto Exchange https://bitcointalk.org/index.php?topic=5027091.msg50417196#msg50417196
Mar 27, 2019 - Disclosure on Large Buying on NENG at ShorelineCrypto Exchange https://bitcointalk.org/index.php?topic=5027091.msg50332097#msg50332097
Mar 17, 2019 - Disclosure on Large Buying on NENG at ShorelineCrypto Exchange https://bitcointalk.org/index.php?topic=5027091.msg50208194#msg50208194
Feb 26, 2019 - Community Project - NewEnglandcoin Graphic Redesign Bounty Initiated https://bitcointalk.org/index.php?topic=5027091.msg49931305#msg49931305
Feb 22, 2019 - Dev Policy on Checkpoints on NewEnglandcoin https://bitcointalk.org/index.php?topic=5027091.msg49875242#msg49875242
Feb 20, 2019 - NewEnglandCoin v1.2.1 Released to Secure the Hard Kork https://bitcointalk.org/index.php?topic=5027091.msg49831059#msg49831059
Feb 11, 2019 - NewEnglandCoin v1.2.0 Released, Anti-51% Attack, Anti-instant Mining after Hard Fork https://bitcointalk.org/index.php?topic=5027091.msg49685389#msg49685389
Jan 13, 2019 - Cheetah_CpuMiner added support for CPU Mining on Mac https://bitcointalk.org/index.php?topic=5027091.msg49218760#msg49218760
Jan 12, 2019 - NENG Core v1.1.2 Released to support MacOS OSX Wallet https://bitcointalk.org/index.php?topic=5027091.msg49202088#msg49202088
Jan 2, 2019 - Cheetah_Cpuminer v1.1.0 is released for both Linux and Windows https://bitcointalk.org/index.php?topic=5027091.msg49004345#msg49004345
Dec 31, 2018 - Technical Whitepaper is Released https://bitcointalk.org/index.php?topic=5027091.msg48990334#msg48990334
Dec 28, 2018 - Cheetah_Cpuminer v1.0.0 is released for Linux https://bitcointalk.org/index.php?topic=5027091.msg48935135#msg48935135
Update on Dec 14, 2018 - NENG Blockchain Stuck Issue https://bitcointalk.org/index.php?topic=5027091.msg48668375#msg48668375
Nov 27, 2018 - Exclusive for PC CPU Miners - How to Steal a Block from ASIC Miners https://bitcointalk.org/index.php?topic=5027091.msg48258465#msg48258465
Nov 28, 2018 - How to CPU Mine a NENG block with window/linux PC https://bitcointalk.org/index.php?topic=5027091.msg48298311#msg48298311
Nov 29, 2018 - A Warning to ASIC Miners https://bitcointalk.org/index.php?topic=5027091.msg48324708#msg48324708
Disclosure: Dev Team Came from ShorelineCrypto, a US based Informatics Service Business offering Fee for service for Coin Creation, Coin Exchange Listing, Blockchain Consulting, etc.
submitted by honglu69 to NewEnglandCoin [link] [comments]

What is really happening in the bitcoin mining process?

What is really happening in the bitcoin mining process?
April 30, 2020 | There’s more than just the sound of thousands of vacuums
It is very easy to just silo the arcane bitcoin mining process as just a bunch of machines computing mathematical algorithms. Although for the most part this is true, and the veracity of this is not far off from the real truth, but what we see on the surface is not identical to what we see below the surface. Understanding bitcoin mining goes beyond the USB enabled ASIC miners we are accustomed to see on every thumbnail article we come across related to this industry.

It’s easy to understand why newbies halt their understanding of bitcoin mining to just state-of-the-art supercomputers with cool flickering neon green lights.
The following below is taken from the masterpiece of a novel, “Mastering Bitcoin”, by the great Andreas Antonopolous. As elegant as it sounds, its best to restate Andreas’ explanation of emergent consensus.
“Satoshi Nakamoto’s main invention is the decentralized mechanism for emergent consensus. Emergent, because consensus is not achieved explicitly — there is no election or fixed moment when consensus occurs. Instead, consensus is an emergent artifact of the asynchronous interaction of thousands of independent nodes, all following simple rules. All the properties of bitcoin, including currency, transactions, payments, and the security model that does not depend on central authority or trust, derive from this invention.
Bitcoin’s decentralized consensus emerges from the interplay of four processes that occur independently on nodes across the network:
  • Independent verification of each transaction, by every full node, based on a comprehensive list of criteria
  • Independent aggregation of those transactions into new blocks by mining nodes, coupled with demonstrated computation through a proof-of-work algorithm
  • Independent verification of the new blocks by every node and assembly into a chain
  • Independent selection, by every node, of the chain with the most cumulative computation demonstrated through proof of work”
The following is a scenario taken from the book as well which excellently demonstrates what is going on with a mining node and its corresponding connected miner machine:
“A mining node is listening for transactions, trying to mine a new block and also listening for blocks discovered by other nodes. The arrival of this block signifies the end of the competition for block 277,315 and the beginning of the competition to create block 277,316. During the previous 10 minutes, while Jing’s node was searching for a solution to block 277,315, it was also collecting transactions in preparation for the next block. By now it has collected a few hundred transactions in the memory pool. Upon receiving block 277,315 and validating it, Jing’s node will also check all the transactions in the memory pool and remove any that were included in block 277,315. Whatever transactions remain in the memory pool are unconfirmed and are waiting to be recorded in a new block. Jing’s node immediately constructs a new empty block, a candidate for block 277,316. This block is called a candidate block because it is not yet a valid block, as it does not contain a valid proof of work. The block becomes valid only if the miner succeeds in finding a solution to the proof-of-work algorithm.
These specialized machines are connected to his mining node over USB. Next, the mining node running on Jing’s desktop transmits the block header to his mining hardware, which starts testing trillions of nonces per second.”
That is essentially the process of what a miner machine and a mining node is going through each every second it is hooked up to the network. Of course this is just a high level overview with a bland taste but one could go more in depth by reading the book mentioned.
Source:
1.Mastering Bitcoin: Unlocking Digital Cryptocurrencies 1st Edition, by Andreas M. Antonopoulos, O’Reilly Media; 1 edition (December 20, 2014)
submitted by 1TMine to u/1TMine [link] [comments]

The Next Crypto Wave: The Rise of Stablecoins and its Entry to the U.S. Dollar Market

The Next Crypto Wave: The Rise of Stablecoins and its Entry to the U.S. Dollar Market

Author: Christian Hsieh, CEO of Tokenomy
This paper examines some explanations for the continual global market demand for the U.S. dollar, the rise of stablecoins, and the utility and opportunities that crypto dollars can offer to both the cryptocurrency and traditional markets.
The U.S. dollar, dominant in world trade since the establishment of the 1944 Bretton Woods System, is unequivocally the world’s most demanded reserve currency. Today, more than 61% of foreign bank reserves and nearly 40% of the entire world’s debt is denominated in U.S. dollars1.
However, there is a massive supply and demand imbalance in the U.S. dollar market. On the supply side, central banks throughout the world have implemented more than a decade-long accommodative monetary policy since the 2008 global financial crisis. The COVID-19 pandemic further exacerbated the need for central banks to provide necessary liquidity and keep staggering economies moving. While the Federal Reserve leads the effort of “money printing” and stimulus programs, the current money supply still cannot meet the constant high demand for the U.S. dollar2. Let us review some of the reasons for this constant dollar demand from a few economic fundamentals.

Demand for U.S. Dollars

Firstly, most of the world’s trade is denominated in U.S. dollars. Chief Economist of the IMF, Gita Gopinath, has compiled data reflecting that the U.S. dollar’s share of invoicing was 4.7 times larger than America’s share of the value of imports, and 3.1 times its share of world exports3. The U.S. dollar is the dominant “invoicing currency” in most developing countries4.

https://preview.redd.it/d4xalwdyz8p51.png?width=535&format=png&auto=webp&s=9f0556c6aa6b29016c9b135f3279e8337dfee2a6

https://preview.redd.it/wucg40kzz8p51.png?width=653&format=png&auto=webp&s=71257fec29b43e0fc0df1bf04363717e3b52478f
This U.S. dollar preference also directly impacts the world’s debt. According to the Bank of International Settlements, there is over $67 trillion in U.S. dollar denominated debt globally, and borrowing outside of the U.S. accounted for $12.5 trillion in Q1 20205. There is an immense demand for U.S. dollars every year just to service these dollar debts. The annual U.S. dollar buying demand is easily over $1 trillion assuming the borrowing cost is at 1.5% (1 year LIBOR + 1%) per year, a conservative estimate.

https://preview.redd.it/6956j6f109p51.png?width=487&format=png&auto=webp&s=ccea257a4e9524c11df25737cac961308b542b69
Secondly, since the U.S. has a much stronger economy compared to its global peers, a higher return on investments draws U.S. dollar demand from everywhere in the world, to invest in companies both in the public and private markets. The U.S. hosts the largest stock markets in the world with more than $33 trillion in public market capitalization (combined both NYSE and NASDAQ)6. For the private market, North America’s total share is well over 60% of the $6.5 trillion global assets under management across private equity, real assets, and private debt investments7. The demand for higher quality investments extends to the fixed income market as well. As countries like Japan and Switzerland currently have negative-yielding interest rates8, fixed income investors’ quest for yield in the developed economies leads them back to the U.S. debt market. As of July 2020, there are $15 trillion worth of negative-yielding debt securities globally (see chart). In comparison, the positive, low-yielding U.S. debt remains a sound fixed income strategy for conservative investors in uncertain market conditions.

Source: Bloomberg
Last, but not least, there are many developing economies experiencing failing monetary policies, where hyperinflation has become a real national disaster. A classic example is Venezuela, where the currency Bolivar became practically worthless as the inflation rate skyrocketed to 10,000,000% in 20199. The recent Beirut port explosion in Lebanon caused a sudden economic meltdown and compounded its already troubled financial market, where inflation has soared to over 112% year on year10. For citizens living in unstable regions such as these, the only reliable store of value is the U.S. dollar. According to the Chainalysis 2020 Geography of Cryptocurrency Report, Venezuela has become one of the most active cryptocurrency trading countries11. The demand for cryptocurrency surges as a flight to safety mentality drives Venezuelans to acquire U.S. dollars to preserve savings that they might otherwise lose. The growth for cryptocurrency activities in those regions is fueled by these desperate citizens using cryptocurrencies as rails to access the U.S. dollar, on top of acquiring actual Bitcoin or other underlying crypto assets.

The Rise of Crypto Dollars

Due to the highly volatile nature of cryptocurrencies, USD stablecoin, a crypto-powered blockchain token that pegs its value to the U.S. dollar, was introduced to provide stable dollar exposure in the crypto trading sphere. Tether is the first of its kind. Issued in 2014 on the bitcoin blockchain (Omni layer protocol), under the token symbol USDT, it attempts to provide crypto traders with a stable settlement currency while they trade in and out of various crypto assets. The reason behind the stablecoin creation was to address the inefficient and burdensome aspects of having to move fiat U.S. dollars between the legacy banking system and crypto exchanges. Because one USDT is theoretically backed by one U.S. dollar, traders can use USDT to trade and settle to fiat dollars. It was not until 2017 that the majority of traders seemed to realize Tether’s intended utility and started using it widely. As of April 2019, USDT trading volume started exceeding the trading volume of bitcoina12, and it now dominates the crypto trading sphere with over $50 billion average daily trading volume13.

https://preview.redd.it/3vq7v1jg09p51.png?width=700&format=png&auto=webp&s=46f11b5f5245a8c335ccc60432873e9bad2eb1e1
An interesting aspect of USDT is that although the claimed 1:1 backing with U.S. dollar collateral is in question, and the Tether company is in reality running fractional reserves through a loose offshore corporate structure, Tether’s trading volume and adoption continues to grow rapidly14. Perhaps in comparison to fiat U.S. dollars, which is not really backed by anything, Tether still has cash equivalents in reserves and crypto traders favor its liquidity and convenience over its lack of legitimacy. For those who are concerned about Tether’s solvency, they can now purchase credit default swaps for downside protection15. On the other hand, USDC, the more compliant contender, takes a distant second spot with total coin circulation of $1.8 billion, versus USDT at $14.5 billion (at the time of publication). It is still too early to tell who is the ultimate leader in the stablecoin arena, as more and more stablecoins are launching to offer various functions and supporting mechanisms. There are three main categories of stablecoin: fiat-backed, crypto-collateralized, and non-collateralized algorithm based stablecoins. Most of these are still at an experimental phase, and readers can learn more about them here. With the continuous innovation of stablecoin development, the utility stablecoins provide in the overall crypto market will become more apparent.

Institutional Developments

In addition to trade settlement, stablecoins can be applied in many other areas. Cross-border payments and remittances is an inefficient market that desperately needs innovation. In 2020, the average cost of sending money across the world is around 7%16, and it takes days to settle. The World Bank aims to reduce remittance fees to 3% by 2030. With the implementation of blockchain technology, this cost could be further reduced close to zero.
J.P. Morgan, the largest bank in the U.S., has created an Interbank Information Network (IIN) with 416 global Institutions to transform the speed of payment flows through its own JPM Coin, another type of crypto dollar17. Although people argue that JPM Coin is not considered a cryptocurrency as it cannot trade openly on a public blockchain, it is by far the largest scale experiment with all the institutional participants trading within the “permissioned” blockchain. It might be more accurate to refer to it as the use of distributed ledger technology (DLT) instead of “blockchain” in this context. Nevertheless, we should keep in mind that as J.P. Morgan currently moves $6 trillion U.S. dollars per day18, the scale of this experiment would create a considerable impact in the international payment and remittance market if it were successful. Potentially the day will come when regulated crypto exchanges become participants of IIN, and the link between public and private crypto assets can be instantly connected, unlocking greater possibilities in blockchain applications.
Many central banks are also in talks about developing their own central bank digital currency (CBDC). Although this idea was not new, the discussion was brought to the forefront due to Facebook’s aggressive Libra project announcement in June 2019 and the public attention that followed. As of July 2020, at least 36 central banks have published some sort of CBDC framework. While each nation has a slightly different motivation behind its currency digitization initiative, ranging from payment safety, transaction efficiency, easy monetary implementation, or financial inclusion, these central banks are committed to deploying a new digital payment infrastructure. When it comes to the technical architectures, research from BIS indicates that most of the current proofs-of-concept tend to be based upon distributed ledger technology (permissioned blockchain)19.

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These institutional experiments are laying an essential foundation for an improved global payment infrastructure, where instant and frictionless cross-border settlements can take place with minimal costs. Of course, the interoperability of private DLT tokens and public blockchain stablecoins has yet to be explored, but the innovation with both public and private blockchain efforts could eventually merge. This was highlighted recently by the Governor of the Bank of England who stated that “stablecoins and CBDC could sit alongside each other20”. One thing for certain is that crypto dollars (or other fiat-linked digital currencies) are going to play a significant role in our future economy.

Future Opportunities

There is never a dull moment in the crypto sector. The industry narratives constantly shift as innovation continues to evolve. Twelve years since its inception, Bitcoin has evolved from an abstract subject to a familiar concept. Its role as a secured, scarce, decentralized digital store of value has continued to gain acceptance, and it is well on its way to becoming an investable asset class as a portfolio hedge against asset price inflation and fiat currency depreciation. Stablecoins have proven to be useful as proxy dollars in the crypto world, similar to how dollars are essential in the traditional world. It is only a matter of time before stablecoins or private digital tokens dominate the cross-border payments and global remittances industry.
There are no shortages of hypes and experiments that draw new participants into the crypto space, such as smart contracts, new blockchains, ICOs, tokenization of things, or the most recent trends on DeFi tokens. These projects highlight the possibilities for a much more robust digital future, but the market also needs time to test and adopt. A reliable digital payment infrastructure must be built first in order to allow these experiments to flourish.
In this paper we examined the historical background and economic reasons for the U.S. dollar’s dominance in the world, and the probable conclusion is that the demand for U.S. dollars will likely continue, especially in the middle of a global pandemic, accompanied by a worldwide economic slowdown. The current monetary system is far from perfect, but there are no better alternatives for replacement at least in the near term. Incremental improvements are being made in both the public and private sectors, and stablecoins have a definite role to play in both the traditional and the new crypto world.
Thank you.

Reference:
[1] How the US dollar became the world’s reserve currency, Investopedia
[2] The dollar is in high demand, prone to dangerous appreciation, The Economist
[3] Dollar dominance in trade and finance, Gita Gopinath
[4] Global trades dependence on dollars, The Economist & IMF working papers
[5] Total credit to non-bank borrowers by currency of denomination, BIS
[6] Biggest stock exchanges in the world, Business Insider
[7] McKinsey Global Private Market Review 2020, McKinsey & Company
[8] Central banks current interest rates, Global Rates
[9] Venezuela hyperinflation hits 10 million percent, CNBC
[10] Lebanon inflation crisis, Reuters
[11] Venezuela cryptocurrency market, Chainalysis
[12] The most used cryptocurrency isn’t Bitcoin, Bloomberg
[13] Trading volume of all crypto assets, coinmarketcap.com
[14] Tether US dollar peg is no longer credible, Forbes
[15] New crypto derivatives let you bet on (or against) Tether’s solvency, Coindesk
[16] Remittance Price Worldwide, The World Bank
[17] Interbank Information Network, J.P. Morgan
[18] Jamie Dimon interview, CBS News
[19] Rise of the central bank digital currency, BIS
[20] Speech by Andrew Bailey, 3 September 2020, Bank of England
submitted by Tokenomy to tokenomyofficial [link] [comments]

How does the BitQT App work?

How does the BitQT App work?

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In the later part of websites are the testimonials screaming out loud regarding their success.BitQT review can be quiet judgemental at this point as a result of neither these testimonials prove the legitimacy of the web site nor the live profit reviews account such
You extremely want to understand that if you opt to speculate you’ll surely not visiting recover. TheBitQT just prove this by themselves stating it not being on affiliate terms with others. Something that’s claiming that you simply’ll earn 110zero greenbacks every day is doing a true-time scam job
Perhaps, theBitQT states advertising itself on Times, CNN and Forbes however neither of them found supportive during this regard. You'll check it all by yourself. This is often the sound proof of its scamming regime throughout the globe
It doesn’t have that laser-accurate performance as in trading bitcoin you can never guarantee the minimum amount of profit you be earning the other day. Its what happens when trading with Forex

Many of the websites agree onto the proficiency ofBitQT negating the crucial and impactful proves I shared with you higher than. They are saying it’s flawless. Will something be this flawless letting you earn regarding one thousand bucks each day without charging a penny? The automated transactions are known to be deposited directly into the user’s account that is nowhere to find affiliation with. Undoubtedly, most of the revealing sites have the only supportive argument beginning with, ‘As the review suggests’. Do raise yourselves, is that this the legitimate way to prove legitimacy ofBitQT
They too argue regarding the legitimate verification method. That’s the explanation why there’s a number of complaints with reference to the current. If these products would have really worked, why not each single person select to remain off from their offices integrating with it somehow:

Merely head to the SIGN-UP section on theBitQT site, fill in your personal info, and present your registration. When acknowledged, you'll be able to be able to access our restrictive Bitcoin exchanging

To induce your exchange account in progress, you’ll have to include some assets. WithBitQT, you can create a initial investment of as low as $250, although you'll be able to contribute as a lot of as you wantoy
Since your enlistment has been acknowledged and you’ve invested some funds, you’re fully done. Simply click on ‘trade’ to receive the rewards ofBitQT’s highly rated algorithm. In case you need a hands-on approach, you can shift to manual operation by changing the settings

There’s no harm in trading in terms of cryptocurrency. We have a tendency to’re not against it. But we tend to really aim to reveal the very fact thatBitQT isn't a legitimate website to believe during this case. To actually invest in bitcoin you initially want to shop for a bitcoin wallet so as to store all bitcoins. a series of blockchain integrations which permits you to top-up and earn.

But, as stated earlier you’ve no actual guarantee concerning the number you wish to earn. Secondly, you wish to integrate your bitcoin wallet to your account and then you’ll be ready to head towards the foremost step. Here, you’ll jin a bitcoin exchange system for trading bitcoin for any different traditional currencies of the market.

It works well solely if you for legitimate sites for functioning and planning. Perhaps, it too needs a nice amount of ability and we never promise you to begin earning when you join Bitcoin Exchanger somehow. This was all aboutBitQT Review as a full fulling the aim of alerting the scam going around.


Money Forex Cluster scamThe Cash Forex Group is run by a company named CFxG which allegedly was founded by a team of experts in all kinds of areas, mainly education in the monetary trading field and network promoting.

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These experts and their automated trading system will supposedly facilitate your to form heaps of cash. In trading solely you'll allegedly make fifteenp.c weekly on your investments. Then there are referral programs and multi-level structures that can boost your income even more. Is that t
Money FX Group scamLet’s begin this Money Forex Group review by stating the obvious, this scheme may be a total scam, you just have to look at the numbers.BitQT

When they promise you fifteen%+ weekly, it means that 60percent+ monthly, which is totally ridiculous in the important world. It means a lot of than 560zeropercent per year, therefore you'd need solely $18,00zero greenbacks to become a millionaire within year. And this is often plain impossible.

No legitimate business can create you a gradual fifteenpercent weekly, no financial markets are that predictable and that easy to trade. It may appear straightforward to you, but it really is this straightforward, a program promising fifteenp.c weekly should be a scam, there is no alternative method, the Money FX Group is a scam.

However there is additional to go through in this review.
Massive lies

Money FX Cluster testimonialThe Money Forex Cluster claims to be regulated by the subsequent institutions: FAC – Financial Conduct Authority of London, DFSA – Monetary Services Authority in Dubai, FSCA – Monetary Sector Conduct Authority of South Africa and FSA – the Monetary Services Authority of Seychelles.

But guess what, the FAC will not even exist, while the others (DFSA, FSCA and FSA) haven't issued any license whatsoever to Cash Forex Cluster. Therefore not only Money FX Group is not regulated at all, it conjointly is lying huge time regarding its regulatory status.

The fact is that it's no license whatsoever, so it cannot supply investment services legally in most countries.

This is often conjointly why they want you to deposit cryptocurrencies, they wish to remain as anonymous as potential, so that they will run away along with your cash.
Regulatory warning

Not long when we have a tendency to printed our analysis, the Financial Conduct Authority (financial regulator in Nice Britain) came up with its own warning.

The regulator said that CashFX is providing investment services without the mandatory authorization and advised the public to remain off from it. This is often a very serious argumentBiTQT.

It'd be terribly unwise to deposit money with an unregulated and basically anonymous entity, as a result of it would not be protected in any means. No matter where the cash finally ends up, this program is promising you impossible returns on investments, which in itself confirms that something is wrong.
How it works

Let’s end this Cash Forex Group review by explaining the essential principle of this investment program. It's a Ponzi theme that does no real economic activity. It just collects money from individuals and may pay out some profits, but the most recent clients’ deposits can be used for that.

This will have an inevitable outcome, the system can sooner or later crumble. It's simply a matter of your time when there can be not enough deposits to hide withdrawals and also the inevitable end can

Nobody has not been paid, that is NOBODY ….. after all you can't compound or upgrade your CFX account unless you withdraw (get paid) …. CFX are not regulated…. as a result of they use a Regulated broker (everfx) to trade…so that information is also incorrect…and judging by the actual members comments….I’d say, members are happy….. long might that continue. BUT, you must never place in more than you are prepared to lose (In SOMETHING). However do correct analysis, ask

members, don’t rely on people that play safe and stay poor. Do your own due diligence. (ps MOST sites that decision each business out as a scam…have their own links…..promoting guess what ? ….tip. SCAMS ! Beware.

https://www.cryptoerapro.com/bitqt/


http://www.cryptoerapro.com/

https://twitter.com/cryptoerapro

https://www.instagram.com/cryptoerapro/

https://www.pinterest.co.uk/cryptoerapro/

https://www.facebook.com/cryptoerapro
submitted by bitqtadvantage to u/bitqtadvantage [link] [comments]

Kleiman's Response to Wright's Sanctions Appeal

submitted by Zectro to bsv [link] [comments]

08-31 07:38 - 'I would appreciate if you explained how I'm wrong. I once wrote a Bitcoin miner (which connects to a stratum mining pool), and have dived quite deep into the math, data structures and algorithms behind Bitcoin, so I think I kn...' by /u/mort96 removed from /r/Bitcoin within 475-485min

'''
I would appreciate if you explained how I'm wrong. I once wrote a Bitcoin miner (which connects to a stratum mining pool), and have dived quite deep into the math, data structures and algorithms behind Bitcoin, so I think I know what I'm talking about, but I'm always receptive to a well-reasoned explanation of how I'm wrong so that I can learn something new.
'''
Context Link
Go1dfish undelete link
unreddit undelete link
Author: mort96
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A breakdown of the aelf blockchain whitepaper — Part 2

A breakdown of the aelf blockchain whitepaper — Part 2

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Breaking down the aelf side-chain

Cloud computing, parallel processing, and AEDPoS have greatly improved the execution performance of any kind of smart contract, but when they are applied to enterprise-level scenarios, new problems crop up. To begin with, in software design, it is a rather bad idea to program all the methods in the same class. We always write a series of classes to inherit a base class, in order to decouple the functionalities and make the class extensible whenever needed. The same also applies to blockchain design. Second, since all the data and transactions are accessible to anyone through a blockchain explorer, if we put the smart contract and data of different enterprises or government sectors on a single blockchain, then everyone can see them, which means there will be no data privacy. Although there are encryption techniques which can mask data, such as zero knowledge proof, it is always better to put the data of different enterprises on different blockchains.
Based on these considerations, long before other projects even realized it, aelf proposed that side-chain technology should be applied to this scenario. Unfortunately, for someone who is new to blockchain, it is almost impossible to understand how side-chain works. Side-chain is not what it literally means, it is not subordinate to the main chain. On the contrary, a side chain is a blockchain distributed system with the same functions and nodes as a main chain (say, the aelf blockchain). As mentioned above, we can put the data of different enterprises on different blockchains. This means we can build many blockchains, and work magic (of course not magic in its literal sense) to make these chains connect to the aelf main chain (in fact, we can call any of these blockchains a main chain and the rest side chains). Currently, the most popular method of connecting any two blockchains, which we also call cross-chain, is using a middle-man. When we want to use bitcoin to play a decentralized game on Ethereum, we need to send a transaction with some amount of bitcoin to a locking bitcoin address, then the middle-man will exchange the locked BTC for ETH at a certain exchange rate and allocate to you the equivalent amount of ETH on Ethereum, which you can use for playing games.
But in aelf, we use a metadata indexing method, which is more straightforward. Unlike other projects who built on the blockchains of those already successful projects (such as Ethereum or the HyperLedger fabric framework for consortium blockchains), the aelf team has writen all the code and build the infrastructure from scratch. From the beginning, the aelf team has defined how the data structure of a blockchain, a block, a transaction etc. should look like in C#. In an aelf blockchain data structure, there is an attribute called blockchain ID, which is a unique hash; and in block data structure, there are several attributes called blockchain ID , Merkle tree root and related side chain block list. There is also one more important thing: all of aelf’s data structures are serialized and stored in Redis (a popular key-value pair database system), so is the side chain information. As a result, as the aelf main chain is growing with block production by BPs, other side chains can send transactions to cross-chain contracts, which then execute the related code to connect to the main chain’s network port and request the main chain to index the side chain block and pay the indexing fee.
The core issue here is how to index a side chain: when a main chain (the block data structure on the main chain, or the data records with main chain ID in Redis), receives a request from a side chain, it adds the side chain’s block head data structure to the related side chain block list, which means theoretically we have indexed or related a side chain. We have mentioned that there is also a blockchain ID in each block, this attribute allows a main chain to index blocks from different side chains. When a user on a main chain wants to access data on a side chain or vise versa, they just need to find the target block on the main chain and its related side chain block list, and then find the target block on the side chain via key indexing.
As we will explain later, blockchains for different application scenarios generate blocks at different speeds. Under such circumstances, a chain with slower speed might index many blocks from a chain that produces blocks faster. This method can be applied to scenarios such as forking.
In practice, we can build any number of blockchains, and relate it via indexing to the aelf main chain, with a specific category of smart contracts running on each of them. For example, we can allow only banking-related smart contracts deployed on a specific blockchain, and e-commerce smart contracts on another. Our whitepaper summarizes it best:
One chain, one contract.
Moreover, the indexing method can make many blockchains into a hierarchical tree structure, the root being the so-called main chain. That’s because a related blockchain can then again index another blockchain as its side chain, and the process can keep going on. Logically, this is in perfect accordance with hierarchical taxonomy, for example, the financial sector has many subcategories, such as banking, lending, investment and insurance, and under investment banking, there are venture capital, investment bank etc… Each subcategory is supported by an indexed blockchain.
So how do these blockchains collaborate in a distributed system? First we need to be know that any node in a distributed system is just a software instance running on your computer, or a process. In TCP/IP, a node is allocated a port number, so we can run any number of this type of instances on a computer. However, each instance has its own port number: we can run several blockchain nodes, one IPFS node, one bit-torrent node and etc. simultaneously. In aelf, you should first start a main chain instance, and then you can build and run a side chain instance. Transactions broadcast on the side chain are collected by the BP nodes (block production nodes) on the main chain. When smart contracts deployed on the side chain is triggered, the BP and full nodes on the main chain will run them.

Aelf — a blockchain based operating system

To perfect the design of our software system, aelf made the system extensible, flexible and pluggable. Just as there are thousands of Linux OS with only one Linux kernel. As Ethereum Founder Vitalik Buterin has explained, Ethereum can be seen as a world computer because there are lots of smart contracts running on it, and the contract execution results are consistent in all the distributed systems around the world. This idea is also embedded in aelf’s system and we call it a “blockchain infrastructure operating system”, or a distributed operating system.
Just like any OS, aelf has a kernel and a shell. In fact, aelf’s kernel is not something like a Linux kernel, it is just an analogy. There is a special concept in aelf’s kernel called the minimum viable blockchain system, which defines the most fundamental aspect of a blockchain. If a developer wants to create a new blockchain system or a new blockchain project, he does’t have to start from scratch, instead, he can directly extend and customize using the aelf blockchain open-source code. The technologies described above are all included in the minimum viable blockchain system. With these, anyone can customize:
  • Block property: block data structure, block packaging speed, transaction data structure, etc.
  • Consensus type: AEDPoS is used by default, but you can also use incentive consensus, like PoW and PoS. And you can also use the consensus of traditional distributed systems, like PoS and Practical Byzantine Fault Tolerance, or PBFT. In fact, the f evil nodes of 3f+1 nodes are the upper limit for any distributed system to reach a consensus, which is called the Byzantine Fault Tolerance, or BFT. In order to do this, there is a specific algorithm, but in 1999, a much more efficient algorithm to reach this consensus came along, that is the PBFT. In scenarios like private blockchain or consortium blockchain where there is no need for a incentive model, PBFT will be a good option.
  • Smart contract collection: In aelf, there are many predefined smart contracts that can be used directly by other contracts, such as token contract, cross-chain contract (also called CCTP, or cross chain transfer protocol), consensus contract, organization voting contracts, etc. Of course, you can also create your own contract with a brand new implementation logic.
  • Others.

Summary

So this is our breakdown of the aelf blockchain whitepaper. In previous articles, we first introduced two basic concepts which are often misinterpreted by other articles. After helping you get these two concepts straight, we then introduced aelf’s vast arsenal of powerful technology. If these articles helped you understand the aelf blockchain better, then I have reached my goal. But I must advise you to read the whitepaper for a more detailed explanation. With all this knowledge at your disposal, I believe you will be much more comfortable developing DApps on aelf.
Check Part 1 here: https://medium.com/aelfblockchain/a-breakdown-of-the-aelf-blockchain-whitepaper-part-1-a63fc2e3e2e7
submitted by Floris-Jan to aelfofficial [link] [comments]

A Glance at the Heart: Proof-of-Authority Technology in the UMI Network

A Glance at the Heart: Proof-of-Authority Technology in the UMI Network

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Greetings from the UMI Team! Our Whitepaper describes in detail the key pros and cons of the two mechanisms which the great majority of other cryptocurrencies are based on:
Proof-of-Work (PoW) — mining technology. Used in Bitcoin, Ethereum, Litecoin, Monero, etc.
Proof-of-Stake (PoS) and its derivatives — forging technology. Used in Nxt, PeerCoin, NEO, PRIZM, etc.
As a result of a careful analysis of PoW and PoS, which are designed to fight against centralization, there came a conclusion that they both fail to perform their main mission and, in the long run, they lead to the network centralization and poor performance. For this reason, we took a different approach. We use Proof-of-Authority (PoA) algorithm coupled with master nodes, which can ensure the UMI network with decentralization and maximum speed.
The Whitepaper allows you to understand the obvious things. This article will give you a clear and detailed explanation of the technology implemented in the UMI network. Let's glance at the heart of the network right now.
Proof-of-Authority: How and Why It Emerged
It's been over a decade since the first transaction in the Bitcoin network. Over this time, the blockchain technology has undergone some qualitative changes. It's down to the fact that the cryptocurrency world seeing the emerging Proof-of-Work defects in the Bitcoin network year after year has actively searched for ways to eliminate them.
PoW decentralization and reliability has an underside of low capacity and scalability problem that prevents the network from rectifying this shortcoming. Moreover, with the growing popularity of Bitcoin, greed of miners who benefit from high fees resulting from the low network throughput has become a serious problem. Miners have also started to create pools making the network more and more centralized. The “human factor” that purposefully slowed down the network and undermined its security could never be eliminated. All this essentially limits the potential for using PoW-based cryptocurrencies on a bigger scale.
Since PoW upgrade ideas came to nothing, crypto community activists have suggested cardinally new solutions and started to develop other protocols. This is how the Proof-of-Stake technology emerged. However, it proved to be excellent in theory rather than in practice. Overall, PoS-based cryptocurrencies do demonstrate a higher capacity, but the difference is not as striking. Moreover, PoS could not fully solve the scalability issue.
In the hope that it could cope with the disaster plaguing all cryptocurrencies, the community came up with brand new algorithms based on alternative operating principles. One of them is the Proof-of-Authority technology. It was meant to be an effective alternative with a high capacity and a solution to the scalability problem. The idea of using PoA in cryptocurrencies was offered by Gavin Wood — a high-profile blockchain programmer and Ethereum co-founder.
Proof-of-Authority Major Features
PoA's major difference from PoW and PoS lies in the elimination of miner or forger races. Network users do not fight for the right to be the first to create a block and receive an award, as it happens with cryptocurrencies based on other technologies. In this case blockchain's operating principle is substantially different — Proof-of-Authority uses the “reputation system” and only allows trusted nodes to create blocks.
It solves the scalability problem allowing to considerably increase capacity and handle transactions almost instantly without wasting time on unnecessary calculations made by miners and forgers. Moreover, trusted nodes must meet the strict capacity requirements. This is one the main reasons why we have selected PoA since this is the only technology allowing to fully use super-fast nodes.
Due to these features, the Proof-of-Authority algorithm is seen as one of the most effective and promising options for bringing blockchain to various business sectors. For instance, its model perfectly fits the logistics and supply chain management sectors. As an outstanding example, PoA is effectively used by the Microsoft Azure cloud platform to offer various tools for bringing blockchain solutions to businesses.
How the UMI Network Gets Rid of the Defects and Incorporates the Benefits of Proof-of-Authority Method
Any system has both drawbacks and advantages — so does PoA. According to the original PoA model, each trusted node can create a block, while it is technically impossible for ordinary users to interfere with the system operation. This makes PoA-based cryptocurrencies a lot more centralized than those based on PoW or PoS. This has always been the main reason for criticizing the PoA technology.
We understood that only a completely decentralized product could translate our vision of a "hard-to-hit", secure and transparent monetary instrument into reality. Therefore, we started with upgrading its basic operating principle in order to create a product that will incorporate all the best features while eliminating the defects. What we’ve got is a decentralized PoA method. We will try to explain at the elementary level:
- We've divided the nodes in the UMI network into two types: master nodes and validator nodes.
- Only master nodes have the right to create blocks and confirm transactions. Among master node holders there's the UMI team and their trusted partners from across the world. Moreover, we deliberately keep some of our partners — those who hold master nodes — in secret in order to secure ourselves against potential negative influence, manipulation, and threats from third parties. This way we ensure maximum coherent and reliable system operation.
- However, since the core idea behind a decentralized cryptocurrency rules out any kind of trust, the blockchain is secured to prevent master nodes from harming the network in the event of sabotage or collusion. It might happen to Bitcoin or other PoW- or PoS-based cryptocurrencies if, for example, several large mining pools unite and perform a 51% attack. But it can’t happen to UMI. First, the worst that bad faith master node holders can do is to negligibly slow down the network. But the UMI network will automatically respond to it by banning such nodes. Thus, master nodes will prevent any partner from doing intentional harm to the network. Moreover, it will not be able to do this, even if most other partners support it. Nothing — not even quantum computers — will help hackers. Read our post "UMI Blockchain Six-Level Security" for more details.
- A validator node can be launched by any participant. Validator nodes maintain the network by verifying the correctness of blocks and excluding the possibility of fakes. In doing so they increase the overall network security and help master nodes carry out their functions. More importantly, those who hold validator nodes control those who hold master nodes and confirm that the latter don't violate anything and comply with the rules. You can find more details about validator nodes in the article we mentioned above.
- Finally, the network allows all interested users to launch light nodes (SPV), which enables viewing and sending transactions without having to download the blockchain and maintain the network. With light nodes, any network user can make sure if the system is operating properly and doesn't have to download the blockchain to do this.
- In addition, we are developing the ability to protect the network in case 100% of the master nodes (10,000 master nodes in total) are "disabled" for some reason. Even this is virtually impossible, we've thought ahead and in the worst-case scenario, the system will automatically move to PoS. By doing so, it will be able to continue processing transactions. We're going to tell you about this in our next publications.
Thus, the UMI network uses an upgraded version of this technology which possesses all its advantages with drawbacks eliminated. This model is truly decentralized and maximum secured.
Another major drawback of PoA-based cryptos is no possibility to grant incentives to users. PoA doesn't imply forging or mining which allow users to earn cryptocurrency while generating new coins. No reward for maintaining the network is the main reason why the crypto community is not interested in PoA. This is, of course, unfair. With this in mind, the UMI team has found the best solution — the unique staking smart-contract. It allows you to increase the number of your coins up to 40% per month even with no mining or forging meaning the human factor cannot have a negative impact on the decentralization and network performance.
New-Generation Proof-of-Authority
The UMI network uses an upgraded version of PoA technology which possesses all its advantages with drawbacks virtually eliminated. This makes UMI a decentralized, easily scalable, and yet the most secure, productive, profitable and fair cryptocurrency, working for the sake of all people.
The widespread use of UMI can change most aspects of society in different areas, including production, commerce, logistics, and all financial arrangements. We are just beginning this journey and thrilled to have you with us. Let's change the world together!
Best regards, UMI Team!
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This is just a theory. What do you guys think?

Just theory if Satoshi wrote the name of the creator which would be 256th puzzle of a puzzle game 14 years ago, and the card has written "find me" in Japanese at side forming this puzzle. Just for looking this picture is it possible to find this gentleman on the internet as the location from the picture been discovered " Kaysersberg, Alsace, France". It would be a great coincidence if the owner of the 256th card was really Satoshi in a ranking of 256 cards? This will be very important figure for 256 Bitcoin value. People might on here might ask why and explain your theory? Well just for a explanation this puzzle is complex and if his card is 256th puzzle card and is a value of 256. What if the answer is 2SHA256 which SHA stands for Secure Hash Algorithm that Bitcoin has been using for mining and address generation. This hash is one of those high security cryptography functions and also the length would have data fix that might contribute of harmony between these blocks.
1.) For example, word would be "squanch" with SHA256 encryption -> “5bfdd901369fbb2ae5052ab5307c74f97651e09bd83e80cf3153952bb81cc7b8”.
2.) satoshi -> DA2876B3EB31EDB4436FA4650673FC6F01F90DE2F1793C4EC332B2387B09726F
3.) Satoshi -> 002688CC350A5333A87FA622EACEC626C3D1C0EBF9F3793DE3885FA254D7E393
** you can play around with it => https://passwordsgenerator.net/sha256-hash-generato **
SHA256 with its code consist 32 bits and 64 digits, so we should not get too far from solving this puzzles some how if this was an method of solving this question via value. Also, the puzzle from this game began in which is called "The city of Perplex". This game has a original concept and also promise reward $200,000 when all the puzzles on the cards are solved. But, think about it f the 256th card is Satoshi that has not been solved it has not been resolved on card number 238. As you can imagine, the 256th card, which is “Satoshi”, has not been resolved. Otherwise, it has not been resolved on card number 238. Hint that our card gives to everyone to solve the puzzle is “ My name is Satoshi ...”. Needless to say with the game has been on the market since 1-2 years before the generation of Bitcoin and Crypto has started. Although I"m also thinking the man might not be Satoshi as his a player, so looking that either looks and style similar is only hope.
submitted by LeftSubstance to FindSatoshi [link] [comments]

Review and Prospect of Crypto Economy-Development and Evolution of Consensus Mechanism (1)

Review and Prospect of Crypto Economy-Development and Evolution of Consensus Mechanism (1)

https://preview.redd.it/7skleasc80a51.png?width=553&format=png&auto=webp&s=fc18cee10bff7b65d5b02487885d936d23382fc8
Table 1 Classification of consensus system
Source: Yuan Yong, Ni Xiaochun, Zeng Shuai, Wang Feiyue, "Development Status and Prospect of Blockchain Consensus Algorithm"
Figure 4 Evolution of consensus algorithm

Figure 4 Evolution of consensus algorithm
Source: Network data

Foreword
The consensus mechanism is one of the important elements of the blockchain and the core rule of the normal operation of the distributed ledger. It is mainly used to solve the trust problem between people and determine who is responsible for generating new blocks and maintaining the effective unification of the system in the blockchain system. Thus, it has become an everlasting research hot topic in blockchain.
This article starts with the concept and role of the consensus mechanism. First, it enables the reader to have a preliminary understanding of the consensus mechanism as a whole; then starting with the two armies and the Byzantine general problem, the evolution of the consensus mechanism is introduced in the order of the time when the consensus mechanism is proposed; Then, it briefly introduces the current mainstream consensus mechanism from three aspects of concept, working principle and representative project, and compares the advantages and disadvantages of the mainstream consensus mechanism; finally, it gives suggestions on how to choose a consensus mechanism for blockchain projects and pointed out the possibility of the future development of the consensus mechanism.
Contents
First, concept and function of the consensus mechanism
1.1 Concept: The core rules for the normal operation of distributed ledgers
1.2 Role: Solve the trust problem and decide the generation and maintenance of new blocks
1.2.1 Used to solve the trust problem between people
1.2.2 Used to decide who is responsible for generating new blocks and maintaining effective unity in the blockchain system
1.3 Mainstream model of consensus algorithm
Second, the origin of the consensus mechanism
2.1 The two armies and the Byzantine generals
2.1.1 The two armies problem
2.1.2 The Byzantine generals problem
2.2 Development history of consensus mechanism
2.2.1 Classification of consensus mechanism
2.2.2 Development frontier of consensus mechanism
Third, Common Consensus System
Fourth, Selection of consensus mechanism and summary of current situation
4.1 How to choose a consensus mechanism that suits you
4.1.1 Determine whether the final result is important
4.1.2 Determine how fast the application process needs to be
4.1.2 Determining the degree to which the application requires for decentralization
4.1.3 Determine whether the system can be terminated
4.1.4 Select a suitable consensus algorithm after weighing the advantages and disadvantages
4.2 Future development of consensus mechanism
Chapter 1 Concept and Function of Consensus Mechanism
1.1 Concept: The core rules for the normal operation of distributed ledgers
Since most cryptocurrencies use decentralized blockchain design, nodes are scattered and parallel everywhere, so a system must be designed to maintain the order and fairness of the system's operation, unify the version of the blockchain, and reward users maintaining the blockchain and punish malicious harmers. Such a system must rely on some way to prove that who has obtained the packaging rights (or accounting rights) of a blockchain and can obtain the reward for packaging this block; or who intends to harm , and will receive certain penalty. Such system is consensus mechanism.
1.2 Role: Solve the trust problem and decide the generation and maintenance of new blocks
1.2.1 Used to solve the trust problem between people
The reason why the consensus mechanism can be at the core of the blockchain technology is that it has formulated a set of rules from the perspective of cryptographic technologies such as asymmetric encryption and time stamping. All participants must comply with this rules. And theese rules are transparent, and cannot be modified artificially. Therefore, without the endorsement of a third-party authority, it can also mobilize nodes across the network to jointly monitor, record all transactions, and publish them in the form of codes, effectively achieving valuable information transfer, solving or more precisely, greatly improving the trust problem between two unrelated strangers who do not trust each other. After all, trusting the objective technology is less risky than trusting a subjective individual.
1.2.2 Used to decide who is responsible for generating new blocks and maintaining effective unity in the blockchain system
On the other hand, in the blockchain system, due to the high network latency of the peer-to-peer network, the sequence of transactions observed by each node is different. To solve this, the consensus mechanism can be used to reach consensus on transactions order within a short period of time to decide who is responsible for generating new blocks in the blockchain system, and to maintain the effective unity of the blockchain.
1.3 The mainstream model of consensus algorithm
The blockchain system is built on the P2P network, and the set of all nodes can be recorded as PP, generally divided into ordinary nodes that produce data or transactions, and"miner" nodes (denoted as M) responsible for mining operations, like verifying, packaging, and updating the data generated by ordinary nodes or transactions. The functions of the two types of nodes may be overlapped; miner nodes usually participate in the consensus competition process in general, and will select certain representative nodes and replace them to participant in the consensus process and compete for accounting rights in specific algorithms. The collection of these representative nodes is recorded as DD; the accounting nodes selected through the consensus process are recorded as AA. The consensus process is repeated in accordance with the round, and each round of the consensus process generally reselects the accounting node for the round . The core of the consensus process is the "select leader" and "accounting" two parts. In the specific operation process, each round can be divided into four stages: Leader election, Block generation, Data validation and Chain updating namely accounting). As shown in Figure 1, the input of the consensus process is the transaction or data generated and verified by the data node, and the output is the encapsulated data block and updated blockchain. The four stages are executed repeatedly, and each execution round will generate a new block.
Stage 1: Leader election
The election is the core of the consensus process, that is, the process of selecting the accounting node AA from all the miner node sets MM: we can use the formula f(M)→f(M)→AA to represent the election process, where the function ff represents the specific implementation of the consensus algorithm. Generally speaking, |A|=1,|A|=1, that is, the only miner node is finally selected to keep accounts.
Stage 2: Block generation
The accounting node selected in the first stage packages the transactions or data generated by all nodes PP in the current time period into a block according to a specific strategy, and broadcasts the generated new block to all miner nodes MM or their representative nodes DD. These transactions or data are usually sorted according to various factors such as block capacity, transaction fees, transaction waiting time, etc., and then packaged into new blocks in sequence. The block generation strategy is a key factor in the performance of the blockchain system, and it also exposes the strategic behavior of miners such as greedy transactions packaging and selfish mining.
Stage 3: Verification
After receiving the broadcasted new block, the miner node MM or the representative node DD will verify the correctness and rationality of the transactions or data encapsulated in the block. If the new block is approved by most verification/representative nodes, the block will be updated to the blockchain as the next block.
Stage 4: On-Chain
The accounting node adds new blocks to the main chain to form a complete and longer chain from the genesis block to the latest block. If there are multiple fork chains on the main chain, the main chain needs to be based on the consensus algorithm judging criteria to choose one of the appropriate fork chain as the main chain.
Chapter 2 The Origin of Consensus Mechanism
2.1 The two armies problems and the Byzantium generals problem
2.1.1 The two armies


Figure 2 Schematic diagram of the two armed forces
Selected from Yuan Yong, Ni Xiaochun, Zeng Shuai, Wang Feiyue, "Development Status and Prospect of Blockchain Consensus Algorithm", Journal of Automation, 2018, 44(11): 2011-2022
As shown in the figure, the 1st and 2nd units of the Blue Army are stationed on two sides of the slope, and cannot communicate remotely between each other. While the White Army is just stationed in the middle of the two Blue Army units. Suppose that the White Army is stronger than either of the two Blue Army units, but it is not as strong as the two Blue Army units combined. If the two units of the Blue Army want to jointly attack the White Army at the same time, they need to communicate with each other, but the White Army is stationed in the middle of them. It is impossible to confirm whether the messengers of two Blue Army units have sent the attack signal to each other, let alone the tampering of the messages. In this case, due to the inability to fully confirm with each other, ultimately no effective consensus can be reached between the two Blue Army units, rendering the "paradox of the two armies".
2.1.2 The Byzantine generals problem


Figure 3 Diagram of the Byzantine generals' problem
Due to the vast territory of the Byzantine roman empire at that time, in order to better achieve the purpose of defense, troops were scattered around the empire, and each army was far apart, and only messengers could deliver messages. During the war, all generals must reach an agreement, or decide whether to attack the enemy based on the majority principle. However, since it is completely dependent on people, if there is a situation where the general rebels or the messenger delivers the wrong message, how can it ensure that the loyal generals can reach agreement without being influenced by the rebels is a problem which was called the Byzantine problem.
The two armies problems and the Byzantine generals problem are all elaborating the same problem: in the case of unreliable information exchange, it is very difficult to reach consensus and coordinate action. The Byzantine general problem is more like a generalization of the "paradox of the two armies".
From the perspective of the computer network, the two armies problem and the Byzantine problem are common contents of computer network courses: the direct communication between two nodes on the network may fail, so the TCP protocol cannot completely guarantee the consistence between the two terminal networks. However, the consensus mechanism can use economic incentives and other methods to reduce this uncertainty to a level acceptable to most people.
It is precisely because of the two armies problem and the Byzantine problem that the consensus mechanism has begun to show its value.
2.2 Development history of consensus mechanism
2.2.1 Classification of consensus mechanism
Because different types of blockchain projects have different requirements for information recording and block generation, and as the consensus mechanism improves due to the development of blockchain technology, there are currently more than 30 consensus mechanisms. These consensus mechanisms can be divided into two categories according to their Byzantine fault tolerance performance: Byzantine fault tolerance system and non-Byzantine fault tolerance system.

Table 1 Classification of consensus mechanism
Source: Yuan Yong, Ni Xiaochun, Zeng Shuai, Wang Feiyue, "Development Status and Prospect of Blockchain Consensus Algorithm"
2.2.2 Development frontier of consensus mechanism
-Development of consensus algorithm
According to the proposed time of the consensus algorithm, we can see relatively clearly the development of the consensus algorithm.
Source: Network data

Figure 4 Development frontier of consensus algorithm

Figure 5 Historical evolution of blockchain consensus algorithm
Source: Yuan Yong, Ni Xiaochun, Zeng Shuai, Wang Feiyue, "Development Status and Prospect of Blockchain Consensus Algorithm"
The consensus algorithm has laid the foundation for the blockchain consensus mechanism. Initially, the research of consensus algorithms was mainly used by computer scientists and computer professors to improve the spam problem or conduct academic discussions.
For example, in 1993, American computer scientist and Harvard professor Cynthia Dwork first proposed the idea of proof of work in order to solve the spam problem; in 1997, the British cryptographer Adam Back also independently proposed to solve the spam problem by use of the mechanism of proof of work for hashing cash and published officially in 2002; in 1999, Markus Jakobsson officially proposed the concept of "proof of work", which laid the foundation for the subsequent design of Satoshi Nakamoto's Bitcoin consensus mechanism.
Next lecture: Chapter 3 Detailed Explanation of Consensus Mechanism Technology
CelesOS
As the first DPOW financial blockchain operating system, CelesOS adopts consensus mechanism 3.0 to break through the "impossible triangle". It provides both high TPS and decentralization. Committed to creating a financial blockchain operating system that embraces regulation, providing services for financial institutions and the development of applications on the regulation chain, and developing a role and consensus eco-system regulation level agreement for regulation.
The CelesOS team is committed to building a bridge between blockchain and regulatory agencies / finance industry. We believe that only blockchain technology that cooperates with regulators will have a bright future and strive to achieve this goal.
📷Website
https://www.celesos.com/
📷 Telegram
https://t.me/celeschain
📷 Twitter
https://twitter.com/CelesChain
📷 Reddit
https://www.reddit.com/useCelesOS
📷 Medium
https://medium.com/@celesos
📷 Facebook
https://www.facebook.com/CelesOS1
📷 Youtube
https://www.youtube.com/channel/UC1Xsd8wU957D-R8RQVZPfGA
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Questions Regarding BTC Mining

I have been wondering about some of the details related to bitcoin mining bit couldn't find an answer, I would bet the answer can be found was I capable of looking up the mining algorithms but I'm not that savvy (not yet at least) so here it goes.
I understand that during mining, the miners take the hash calculated from a given block then appends a nonce to it and calculate SHA256 for the whole expression, if the hash value is larger than the limit set by mining difficulty, the miner must attempt again the SHA256 calculation again by appending a different nonce and repeat until a hash smaller than the limit is found.
What I wanted to ask is the following:
1) Is my understanding above correct? If not then please disregard the below questions since they would be garbage most likely (correcting the fault lines in my understanding would more than enough).
2) How are these nonces to be appended chosen? Are they chosen randomly at every attempt or changed sequentially by adding 1 for example?
3) Does the bitcoin blockchain enforces the use of a specific algorithm for generating nonces or is it left to the miners to concoct their own algorithms as they see fit? (If enforced by the bitcoin block chain, I'd appreciate an explanation why)
4) If the choice is left to miners to generate nonces as they see fit, what is the best approach to generating these nonces available?
5) In a mining pools where many ASICs are hashing together, is there any coordination at the pool or at least at individual ASIC miner level to ensure no two ASIC chips are calculating the hash for the same nonce while trying to find the block? If not, what are the difficulties preventing such an implementation?
Thanks in advance and if there are any useful resources addressing these questions please share them especially ones describing the mining algorithm generating nonces.
submitted by BitcoinAsks to BitcoinMining [link] [comments]

CYPHERIUM ENHACES BLOCKCHAIN TECHNOLOGY

OVERVIEW
Rarely has any technology such as blockchain attracted the public and media organisations. Institutions designed to catalyze the fourth industrial revolution are experimenting with technology, and investors have invested hundreds of millions of dollars in blockchain companies. This is a low-risk, experimental environment with error protection. Innovation is a combination of creativity and implementation. Ideas often must go through an evolutionary or cyclical phase before they are ready for commercialization. In fact, the cycle is so long that it is too expensive, inefficient in terms of time and money to generate and generate ideas, and in most cases almost never reaches commercial value. Thus, almost 99% of venture capital firms fail.
A fast growing technology that has come to enhance the blockchain technology is CYPHERIUM.

CHALLENGES FACING THE BLOCKCHAIN TECHNOLOGY
The Bitcoin framework is one of the most notable usage of blockchain innovations in circulated exchange based frameworks. In Bitcoin, each system hub seeks the benefit of putting away a lot of at least one exchanges in another square of the blockchain by comprehending a complex computational math issue, here and there alluded to as a mining verification of-work (POW). Under current conditions, a lot of exchanges is ordinarily put away in another square of the Bitcoin blockchain at a pace of around one new square like clockwork, and each square has an inexact size of one megabyte (MB). As needs be, the Bitcoin framework is dependent upon a looming versatility issue: as it were 3 to 7 exchanges can be handled every second, which is far underneath the quantity of exchanges handled in other exchange based frameworks, for example, the roughly 30,000 exchanges for each second in the Visa™ exchange framework. The most huge disadvantage of the Nakamoto accord is its absence of irrevocability. Conclusion implies once an exchange or an activity is performed on the blockchain, it is for all time recorded on the blockchain and difficult to turn around. This is fundamental to the wellbeing of money related repayment frameworks as exchanges must not be saved once they are made. For Bitcoin's situation, noxious on-screen characters can alter the exchange history given enough hash power, causing a twofold spending assault, given that there is sufficient motivator and money related practicality to complete such assaults. Given that mining gear leasing and botnets are at present predominant around the world, such an assault has become achievable.
Because of this absence of conclusiveness, Nakamoto accord must depend on additional measures, for example, confirmation of-work to forestall pernicious exercises. This hinders the capacity ofNakamoto accord to scale in light of the fact that a exchange must hang tight for various affirmations before coming to "probabilistic absolution".
In this way, wellbeing isn't ensured by Nakamoto agreement, and so as to secure the system, each exchange must experience extra an ideal opportunity to process. For Bitcoin's situation, an exchange isn't considered last until in any event six affirmations. Since Bitcoin can just process a couple of exchanges every second, the exchange cost is preposterously high, making it unreasonable for little installments like shopping for food or eatery feasting. This extraordinarily frustrates Bitcoin's utilization as an installment strategy in this present reality.

CYPHERIUM SOLUTIONS
Cypherium's exclusive algorithm, CypherBFT conquers burdens of the earlier craftsmanship by giving a circulated exchange framework including a gathering of validator hubs that are known to each other in a system however are undefined to the next system hubs in the system. As utilized thus, the gathering of validator hubs might be alluded to as a "Board of trustees" of validator hubs. In a few explanations, the framework reconfigures at least one validator hubs in the Committee dependent on the consequences of confirmation of-work (POW) challenges. As per some uncovered epitomes, a system hub that isn't as of now a validator hub in the Committee might be added to the Committee on the off chance that it effectively finishes a POW challenge. In such an occasion, the system hub may turn into another validator hub in the Committee, supplanting a current validator hub. In elective epitomes, a system hub may become another validator hub in the Committee dependent on a proof-of-stake (POS) accord. In yet another epitome, a system hub may turn into another validator hub in the Committee dependent on a verification of-authority (POA) agreement. In other elective exemplifications, a system hub may turn into a new validator hub in the Committee dependent on a mix of any of POW, POA, and POS accord.

In some revealed exemplifications, the new validator hub replaces a validator hub in the Committee. The substitution might be founded on a foreordained guideline known by all the hubs in the system. For model, the new validator hub may supplant the most established validator hub in the Committee. As indicated by another model, the new validator hub may supplant a validator hub that has been resolved to have gone disconnected, become bargained (e.g., hacked), fizzled (e.g., because of equipment breakdown), or in any case is inaccessible or not, at this point trusted. In the praiseworthy exemplifications, the circulated framework expect that for an adaptation to non-critical failure of f hubs, the Committee incorporates at any rate 3f +1 validator hubs.
Since the validator hubs in the Committee might be every now and again supplanted, for instance, contingent upon the measure of time required to finish the POW challenges, it is hard for vindictive outsiders to identify the total arrangement of validator hubs in the Committee at some random time.

BENEFITS OF CYPHERIUM BLOCKCHAIN TECHNOLOGY
Cypherium runs its exclusive CypherBFT accord, tied down by the HotStuff calculation, and can genuinely offer moment irrevocability for its system clients. With its HotStuff-based structure, the CypherBFT's runtime keeps going just 20-30 milliseconds (ms). A few affirmations are all that is required to for all time acknowledge a proposed obstruct into the blockchain, and it just takes 90ms for these affirmations to come to pass, making the procedure essentially quicker than the two-minutes required by EOS.
Cypherium's CypherBFT, which additionally uses HotStuff, doesn't have to pick between responsiveness and linearity. Cypherium's double blockchain structure incorporates the velocities of a dag, however its review for clients can occur a lot more straightforward and quicker, which adds to the accessibility of data and makes the data more decentralized.
As per some revealed epitomes, the validator hubs in the Committee may get exchange demands from other system hubs, for instance, in a P2P organize. The Committee may incorporate at any rate one validator hub that fills in as a "Pioneer" validator hub; the other validator hubs might be alluded to as "Partner" validator hubs. The Leader hub might be changed occasionally, on request, or inconsistently by the individuals from the Committee. At the point when any validator hub gets another exchange demand from a non-validator hub in the system, the exchange solicitation might be sent to the entirety of the validator hubs in the Committee. Further to the unveiled epitomes, the Pioneer hub facilitates with the other Associate validator hubs to arrive at an accord of an attitude (e.g., acknowledge or dismiss) for an exchange square containing the exchange solicitation and communicates the accord to the whole P2P arrange. In the event that the accord is to acknowledge or in any case approve the exchange demand, the mentioned exchange might be included another square of a blockchain that is known to in any event a portion of the system hubs in the system.
In conclusion, CYPHERIUM'S distributed smart-contracts block-chain is ideal for a good number of use cases which include (but not limited to):
Finance
Messaging
Voting
Notarization
Digital Agreements (Contracts)
Secure data storage
A.I (Artificial Intelligence)
IoT (Internet of Things
To know more about CYPHERIUM kindly visit the following links:
WEBSITE: https://cypherium.io/
GITHUB: https://github.com/cypherium
WHITEPAPER: https://github.com/cypherium/patent/blob/maste15224.0003%20-%20FINAL%20Draft%20Application%20(originally%200003%20invention%201)%20single%20chain%20in%20pipeline.pdf
TELEGRAM: https://t.me/cypherium_supergroup
TWITTER: http://twitter.com/cypheriumchain
FACEBOOK: https://www.facebook.com/CypheriumChain/
AUTHOR: Nwali Jennifer
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Dive Into Tendermint Consensus Protocol (I)

Dive Into Tendermint Consensus Protocol (I)
This article is written by the CoinEx Chain lab. CoinEx Chain is the world’s first public chain exclusively designed for DEX, and will also include a Smart Chain supporting smart contracts and a Privacy Chain protecting users’ privacy.
longcpp @ 20200618
This is Part 1 of the serialized articles aimed to explain the Tendermint consensus protocol in detail.
Part 1. Preliminary of the consensus protocol: security model and PBFT protocol
Part 2. Tendermint consensus protocol illustrated: two-phase voting protocol and the locking and unlocking mechanism
Part 3. Weighted round-robin proposer selection algorithm used in Tendermint project
Any consensus agreement that is ultimately reached is the General Agreement, that is, the majority opinion. The consensus protocol on which the blockchain system operates is no exception. As a distributed system, the blockchain system aims to maintain the validity of the system. Intuitively, the validity of the blockchain system has two meanings: firstly, there is no ambiguity, and secondly, it can process requests to update its status. The former corresponds to the safety requirements of distributed systems, while the latter to the requirements of liveness. The validity of distributed systems is mainly maintained by consensus protocols, considering the multiple nodes and network communication involved in such systems may be unstable, which has brought huge challenges to the design of consensus protocols.

The semi-synchronous network model and Byzantine fault tolerance

Researchers of distributed systems characterize these problems that may occur in nodes and network communications using node failure models and network models. The fail-stop failure in node failure models refers to the situation where the node itself stops running due to configuration errors or other reasons, thus unable to go on with the consensus protocol. This type of failure will not cause side effects on other parts of the distributed system except that the node itself stops running. However, for such distributed systems as the public blockchain, when designing a consensus protocol, we still need to consider the evildoing intended by nodes besides their failure. These incidents are all included in the Byzantine Failure model, which covers all unexpected situations that may occur on the node, for example, passive downtime failures and any deviation intended by the nodes from the consensus protocol. For a better explanation, downtime failures refer to nodes’ passive running halt, and the Byzantine failure to any arbitrary deviation of nodes from the consensus protocol.
Compared with the node failure model which can be roughly divided into the passive and active models, the modeling of network communication is more difficult. The network itself suffers problems of instability and communication delay. Moreover, since all network communication is ultimately completed by the node which may have a downtime failure or a Byzantine failure in itself, it is usually difficult to define whether such failure arises from the node or the network itself when a node does not receive another node's network message. Although the network communication may be affected by many factors, the researchers found that the network model can be classified by the communication delay. For example, the node may fail to send data packages due to the fail-stop failure, and as a result, the corresponding communication delay is unknown and can be any value. According to the concept of communication delay, the network communication model can be divided into the following three categories:
  • The synchronous network model: There is a fixed, known upper bound of delay $\Delta$ in network communication. Under this model, the maximum delay of network communication between two nodes in the network is $\Delta$. Even if there is a malicious node, the communication delay arising therefrom does not exceed $\Delta$.
  • The asynchronous network model: There is an unknown delay in network communication, with the upper bound of the delay known, but the message can still be successfully delivered in the end. Under this model, the network communication delay between two nodes in the network can be any possible value, that is, a malicious node, if any, can arbitrarily extend the communication delay.
  • The semi-synchronous network model: Assume that there is a Global Stabilization Time (GST), before which it is an asynchronous network model and after which, a synchronous network model. In other words, there is a fixed, known upper bound of delay in network communication $\Delta$. A malicious node can delay the GST arbitrarily, and there will be no notification when no GST occurs. Under this model, the delay in the delivery of the message at the time $T$ is $\Delta + max(T, GST)$.
The synchronous network model is the most ideal network environment. Every message sent through the network can be received within a predictable time, but this model cannot reflect the real network communication situation. As in a real network, network failures are inevitable from time to time, causing the failure in the assumption of the synchronous network model. Yet the asynchronous network model goes to the other extreme and cannot reflect the real network situation either. Moreover, according to the FLP (Fischer-Lynch-Paterson) theorem, under this model if there is one node fails, no consensus protocol will reach consensus in a limited time. In contrast, the semi-synchronous network model can better describe the real-world network communication situation: network communication is usually synchronous or may return to normal after a short time. Such an experience must be no stranger to everyone: the web page, which usually gets loaded quite fast, opens slowly every now and then, and you need to try before you know the network is back to normal since there is usually no notification. The peer-to-peer (P2P) network communication, which is widely used in blockchain projects, also makes it possible for a node to send and receive information from multiple network channels. It is unrealistic to keep blocking the network information transmission of a node for a long time. Therefore, all the discussion below is under the semi-synchronous network model.
The design and selection of consensus protocols for public chain networks that allow nodes to dynamically join and leave need to consider possible Byzantine failures. Therefore, the consensus protocol of a public chain network is designed to guarantee the security and liveness of the network under the semi-synchronous network model on the premise of possible Byzantine failure. Researchers of distributed systems point out that to ensure the security and liveness of the system, the consensus protocol itself needs to meet three requirements:
  • Validity: The value reached by honest nodes must be the value proposed by one of them
  • Agreement: All honest nodes must reach consensus on the same value
  • Termination: The honest nodes must eventually reach consensus on a certain value
Validity and agreement can guarantee the security of the distributed system, that is, the honest nodes will never reach a consensus on a random value, and once the consensus is reached, all honest nodes agree on this value. Termination guarantees the liveness of distributed systems. A distributed system unable to reach consensus is useless.

The CAP theorem and Byzantine Generals Problem

In a semi-synchronous network, is it possible to design a Byzantine fault-tolerant consensus protocol that satisfies validity, agreement, and termination? How many Byzantine nodes can a system tolerance? The CAP theorem and Byzantine Generals Problem provide an answer for these two questions and have thus become the basic guidelines for the design of Byzantine fault-tolerant consensus protocols.
Lamport, Shostak, and Pease abstracted the design of the consensus mechanism in the distributed system in 1982 as the Byzantine Generals Problem, which refers to such a situation as described below: several generals each lead the army to fight in the war, and their troops are stationed in different places. The generals must formulate a unified action plan for the victory. However, since the camps are far away from each other, they can only communicate with each other through the communication soldiers, or, in other words, they cannot appear on the same occasion at the same time to reach a consensus. Unfortunately, among the generals, there is a traitor or two who intend to undermine the unified actions of the loyal generals by sending the wrong information, and the communication soldiers cannot send the message to the destination by themselves. It is assumed that each communication soldier can prove the information he has brought comes from a certain general, just as in the case of a real BFT consensus protocol, each node has its public and private keys to establish an encrypted communication channel for each other to ensure that its messages will not be tampered with in the network communication, and the message receiver can also verify the sender of the message based thereon. As already mentioned, any consensus agreement ultimately reached represents the consensus of the majority. In the process of generals communicating with each other for an offensive or retreat, a general also makes decisions based on the majority opinion from the information collected by himself.
According to the research of Lamport et al, if there are 1/3 or more traitors in the node, the generals cannot reach a unified decision. For example, in the following figure, assume there are 3 generals and only 1 traitor. In the figure on the left, suppose that General C is the traitor, and A and B are loyal. If A wants to launch an attack and informs B and C of such intention, yet the traitor C sends a message to B, suggesting what he has received from A is a retreat. In this case, B can't decide as he doesn't know who the traitor is, and the information received is insufficient for him to decide. If A is a traitor, he can send different messages to B and C. Then C faithfully reports to B the information he received. At this moment as B receives conflicting information, he cannot make any decisions. In both cases, even if B had received consistent information, it would be impossible for him to spot the traitor between A and C. Therefore, it is obvious that in both situations shown in the figure below, the honest General B cannot make a choice.
According to this conclusion, when there are $n$ generals with at most $f$ traitors (n≤3f), the generals cannot reach a consensus if $n \leq 3f$; and with $n > 3f$, a consensus can be reached. This conclusion also suggests that when the number of Byzantine failures $f$ exceeds 1/3 of the total number of nodes $n$ in the system $f \ge n/3$ , no consensus will be reached on any consensus protocol among all honest nodes. Only when $f < n/3$, such condition is likely to happen, without loss of generality, and for the subsequent discussion on the consensus protocol, $ n \ge 3f + 1$ by default.
The conclusion reached by Lamport et al. on the Byzantine Generals Problem draws a line between the possible and the impossible in the design of the Byzantine fault tolerance consensus protocol. Within the possible range, how will the consensus protocol be designed? Can both the security and liveness of distributed systems be fully guaranteed? Brewer provided the answer in his CAP theorem in 2000. It indicated that a distributed system requires the following three basic attributes, but any distributed system can only meet two of the three at the same time.
  1. Consistency: When any node responds to the request, it must either provide the latest status information or provide no status information
  2. Availability: Any node in the system must be able to continue reading and writing
  3. Partition Tolerance: The system can tolerate the loss of any number of messages between two nodes and still function normally

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A distributed system aims to provide consistent services. Therefore, the consistency attribute requires that the two nodes in the system cannot provide conflicting status information or expired information, which can ensure the security of the distributed system. The availability attribute is to ensure that the system can continuously update its status and guarantee the availability of distributed systems. The partition tolerance attribute is related to the network communication delay, and, under the semi-synchronous network model, it can be the status before GST when the network is in an asynchronous status with an unknown delay in the network communication. In this condition, communicating nodes may not receive information from each other, and the network is thus considered to be in a partitioned status. Partition tolerance requires the distributed system to function normally even in network partitions.
The proof of the CAP theorem can be demonstrated with the following diagram. The curve represents the network partition, and each network has four nodes, distinguished by the numbers 1, 2, 3, and 4. The distributed system stores color information, and all the status information stored by all nodes is blue at first.
  1. Partition tolerance and availability mean the loss of consistency: When node 1 receives a new request in the leftmost image, the status changes to red, the status transition information of node 1 is passed to node 3, and node 3 also updates the status information to red. However, since node 3 and node 4 did not receive the corresponding information due to the network partition, the status information is still blue. At this moment, if the status information is queried through node 2, the blue returned by node 2 is not the latest status of the system, thus losing consistency.
  2. Partition tolerance and consistency mean the loss of availability: In the middle figure, the initial status information of all nodes is blue. When node 1 and node 3 update the status information to red, node 2 and node 4 maintain the outdated information as blue due to network partition. Also when querying status information through node 2, you need to first ask other nodes to make sure you’re in the latest status before returning status information as node 2 needs to follow consistency, but because of the network partition, node 2 cannot receive any information from node 1 or node 3. Then node 2 cannot determine whether it is in the latest status, so it chooses not to return any information, thus depriving the system of availability.
  3. Consistency and availability mean the loss of the partition tolerance: In the right-most figure, the system does not have a network partition at first, and both status updates and queries can go smoothly. However, once a network partition occurs, it degenerates into one of the previous two conditions. It is thus proved that any distributed system cannot have consistency, availability, and partition tolerance all at the same time.

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The discovery of the CAP theorem seems to declare that the aforementioned goals of the consensus protocol is impossible. However, if you’re careful enough, you may find from the above that those are all extreme cases, such as network partitions that cause the failure of information transmission, which could be rare, especially in P2P network. In the second case, the system rarely returns the same information with node 2, and the general practice is to query other nodes and return the latest status as believed after a while, regardless of whether it has received the request information of other nodes. Therefore, although the CAP theorem points out that any distributed system cannot satisfy the three attributes at the same time, it is not a binary choice, as the designer of the consensus protocol can weigh up all the three attributes according to the needs of the distributed system. However, as the communication delay is always involved in the distributed system, one always needs to choose between availability and consistency while ensuring a certain degree of partition tolerance. Specifically, in the second case, it is about the value that node 2 returns: a probably outdated value or no value. Returning the possibly outdated value may violate consistency but guarantees availability; yet returning no value deprives the system of availability but guarantees its consistency. Tendermint consensus protocol to be introduced is consistent in this trade-off. In other words, it will lose availability in some cases.
The genius of Satoshi Nakamoto is that with constraints of the CAP theorem, he managed to reach a reliable Byzantine consensus in a distributed network by combining PoW mechanism, Satoshi Nakamoto consensus, and economic incentives with appropriate parameter configuration. Whether Bitcoin's mechanism design solves the Byzantine Generals Problem has remained a dispute among academicians. Garay, Kiayias, and Leonardos analyzed the link between Bitcoin mechanism design and the Byzantine consensus in detail in their paper The Bitcoin Backbone Protocol: Analysis and Applications. In simple terms, the Satoshi Consensus is a probabilistic Byzantine fault-tolerant consensus protocol that depends on such conditions as the network communication environment and the proportion of malicious nodes' hashrate. When the proportion of malicious nodes’ hashrate does not exceed 1/2 in a good network communication environment, the Satoshi Consensus can reliably solve the Byzantine consensus problem in a distributed environment. However, when the environment turns bad, even with the proportion within 1/2, the Satoshi Consensus may still fail to reach a reliable conclusion on the Byzantine consensus problem. It is worth noting that the quality of the network environment is relative to Bitcoin's block interval. The 10-minute block generation interval of the Bitcoin can ensure that the system is in a good network communication environment in most cases, given the fact that the broadcast time of a block in the distributed network is usually just several seconds. In addition, economic incentives can motivate most nodes to actively comply with the agreement. It is thus considered that with the current Bitcoin network parameter configuration and mechanism design, the Bitcoin mechanism design has reliably solved the Byzantine Consensus problem in the current network environment.

Practical Byzantine Fault Tolerance, PBFT

It is not an easy task to design the Byzantine fault-tolerant consensus protocol in a semi-synchronous network. The first practically usable Byzantine fault-tolerant consensus protocol is the Practical Byzantine Fault Tolerance (PBFT) designed by Castro and Liskov in 1999, the first of its kind with polynomial complexity. For a distributed system with $n$ nodes, the communication complexity is $O(n2$.) Castro and Liskov showed in the paper that by transforming centralized file system into a distributed one using the PBFT protocol, the overwall performance was only slowed down by 3%. In this section we will briefly introduce the PBFT protocol, paving the way for further detailed explanations of the Tendermint protocol and the improvements of the Tendermint protocol.
The PBFT protocol that includes $n=3f+1$ nodes can tolerate up to $f$ Byzantine nodes. In the original paper of PBFT, full connection is required among all the $n$ nodes, that is, any two of the n nodes must be connected. All the nodes of the network jointly maintain the system status through network communication. In the Bitcoin network, a node can participate in or exit the consensus process through hashrate mining at any time, which is managed by the administrator, and the PFBT protocol needs to determine all the participating nodes before the protocol starts. All nodes in the PBFT protocol are divided into two categories, master nodes, and slave nodes. There is only one master node at any time, and all nodes take turns to be the master node. All nodes run in a rotation process called View, in each of which the master node will be reelected. The master node selection algorithm in PBFT is very simple: all nodes become the master node in turn by the index number. In each view, all nodes try to reach a consensus on the system status. It is worth mentioning that in the PBFT protocol, each node has its own digital signature key pair. All sent messages (including request messages from the client) need to be signed to ensure the integrity of the message in the network and the traceability of the message itself. (You can determine who sent a message based on the digital signature).
The following figure shows the basic flow of the PBFT consensus protocol. Assume that the current view’s master node is node 0. Client C initiates a request to the master node 0. After the master node receives the request, it broadcasts the request to all slave nodes that process the request of client C and return the result to the client. After the client receives f+1 identical results from different nodes (based on the signature value), the result can be taken as the final result of the entire operation. Since the system can have at most f Byzantine nodes, at least one of the f+1 results received by the client comes from an honest node, and the security of the consensus protocol guarantees that all honest nodes will reach consensus on the same status. So, the feedback from 1 honest node is enough to confirm that the corresponding request has been processed by the system.

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For the status synchronization of all honest nodes, the PBFT protocol has two constraints on each node: on one hand, all nodes must start from the same status, and on the other, the status transition of all nodes must be definite, that is, given the same status and request, the results after the operation must be the same. Under these two constraints, as long as the entire system agrees on the processing order of all transactions, the status of all honest nodes will be consistent. This is also the main purpose of the PBFT protocol: to reach a consensus on the order of transactions between all nodes, thereby ensuring the security of the entire distributed system. In terms of availability, the PBFT consensus protocol relies on a timeout mechanism to find anomalies in the consensus process and start the View Change protocol in time to try to reach a consensus again.
The figure above shows a simplified workflow of the PBFT protocol. Where C is the client, 0, 1, 2, and 3 represent 4 nodes respectively. Specifically, 0 is the master node of the current view, 1, 2, 3 are slave nodes, and node 3 is faulty. Under normal circumstances, the PBFT consensus protocol reaches consensus on the order of transactions between nodes through a three-phase protocol. These three phases are respectively: Pre-Prepare, Prepare, and Commit:
  • The master node of the pre-preparation node is responsible for assigning the sequence number to the received client request, and broadcasting the message to the slave node. The message contains the hash value of the client request d, the sequence number of the current viewv, the sequence number n assigned by the master node to the request, and the signature information of the master nodesig. The scheme design of the PBFT protocol separates the request transmission from the request sequencing process, and the request transmission is not to be discussed here. The slave node that receives the message accepts the message after confirming the message is legitimate and enter preparation phase. The message in this step checks the basic signature, hash value, current view, and, most importantly, whether the master node has given the same sequence number to other request from the client in the current view.
  • In preparation, the slave node broadcasts the message to all nodes (including itself), indicating that it assigns the sequence number n to the client request with the hash value d under the current view v, with its signaturesig as proof. The node receiving the message will check the correctness of the signature, the matching of the view sequence number, etc., and accept the legitimate message. When the PRE-PREPARE message about a client request (from the main node) received by a node matches with the PREPARE from 2f slave nodes, the system has agreed on the sequence number requested by the client in the current view. This means that 2f+1 nodes in the current view agree with the request sequence number. Since it contains information from at most fmalicious nodes, there are a total of f+1 honest nodes that have agreed with the allocation of the request sequence number. With f malicious nodes, there are a total of 2f+1 honest nodes, so f+1represents the majority of the honest nodes, which is the consensus of the majority mentioned before.
  • After the node (including the master node and the slave node) receives a PRE-PREPARE message requested by the client and 2f PREPARE messages, the message is broadcast across the network and enters the submission phase. This message is used to indicate that the node has observed that the whole network has reached a consensus on the sequence number allocation of the request message from the client. When the node receives 2f+1 COMMIT messages, there are at least f+1 honest nodes, that is, most of the honest nodes have observed that the entire network has reached consensus on the arrangement of sequence numbers of the request message from the client. The node can process the client request and return the execution result to the client at this moment.
Roughly speaking, in the pre-preparation phase, the master node assigns a sequence number to all new client requests. During preparation, all nodes reach consensus on the client request sequence number in this view, while in submission the consistency of the request sequence number of the client in different views is to be guaranteed. In addition, the design of the PBFT protocol itself does not require the request message to be submitted by the assigned sequence number, but out of order. That can improve the efficiency of the implementation of the consensus protocol. Yet, the messages are still processed by the sequence number assigned by the consensus protocol for the consistency of the distributed system.
In the three-phase protocol execution of the PBFT protocol, in addition to maintaining the status information of the distributed system, the node itself also needs to log all kinds of consensus information it receives. The gradual accumulation of logs will consume considerable system resources. Therefore, the PBFT protocol additionally defines checkpoints to help the node deal with garbage collection. You can set a checkpoint every 100 or 1000 sequence numbers according to the request sequence number. After the client request at the checkpoint is executed, the node broadcasts messages throughout the network, indicating that after the node executes the client request with sequence number n, the hash value of the system status is d, and it is vouched by its own signature sig. After 2f+1 matching CHECKPOINT messages (one of which can come from the node itself) are received, most of the honest nodes in the entire network have reached a consensus on the system status after the execution of the client request with the sequence numbern, and then you can clear all relevant log records of client requests with the sequence number less than n. The node needs to save these2f+1 CHECKPOINTmessages as proof of the legitimate status at this moment, and the corresponding checkpoint is called a stable checkpoint.
The three-phase protocol of the PBFT protocol can ensure the consistency of the processing order of the client request, and the checkpoint mechanism is set to help nodes perform garbage collection and further ensures the status consistency of the distributed system, both of which can guarantee the security of the distributed system aforementioned. How is the availability of the distributed system guaranteed? In the semi-synchronous network model, a timeout mechanism is usually introduced, which is related to delays in the network environment. It is assumed that the network delay has a known upper bound after GST. In such condition, an initial value is usually set according to the network condition of the system deployed. In case of a timeout event, besides the corresponding processing flow triggered, additional mechanisms will be activated to readjust the waiting time. For example, an algorithm like TCP's exponential back off can be adopted to adjust the waiting time after a timeout event.
To ensure the availability of the system in the PBFT protocol, a timeout mechanism is also introduced. In addition, due to the potential the Byzantine failure in the master node itself, the PBFT protocol also needs to ensure the security and availability of the system in this case. When the Byzantine failure occurs in the master node, for example, when the slave node does not receive the PRE-PREPARE message or the PRE-PREPARE message sent by the master node from the master node within the time window and is thus determined to be illegitimate, the slave node can broadcast to the entire network, indicating that the node requests to switch to the new view with sequence number v+1. n indicates the request sequence number corresponding to the latest stable checkpoint local to the node, and C is to prove the stable checkpoint 2f+1 legitimate CHECKPOINT messages as aforementioned. After the latest stable checkpoint and before initiating the VIEWCHANGE message, the system may have reached a consensus on the sequence numbers of some request messages in the previous view. To ensure the consistency of these request sequence numbers to be switched in the view, the VIEWCHANGE message needs to carry this kind of the information to the new view, which is also the meaning of the P field in the message. P contains all the client request messages collected at the node with a request sequence number greater than n and the proof that a consensus has been reached on the sequence number in the node: the legitimate PRE-PREPARE message of the request and 2f matching PREPARE messages. When the master node in view v+1 collects 2f+1 VIEWCHANGE messages, it can broadcast the NEW-VIEW message and take the entire system into a new view. For the security of the system in combination with the three-phase protocol of the PBFT protocol, the construction rules of the NEW-VIEW information are designed in a quite complicated way. You can refer to the original paper of PBFT for more details.

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VIEWCHANGE contains a lot of information. For example, C contains 2f+1 signature information, P contains several signature sets, and each set has 2f+1 signature. At least 2f+1 nodes need to send a VIEWCHANGE message before prompting the system to enter the next new view, and that means, in addition to the complex logic of constructing the information of VIEWCHANGE and NEW-VIEW, the communication complexity of the view conversion protocol is $O(n2$.) Such complexity also limits the PBFT protocol to support only a few nodes, and when there are 100 nodes, it is usually too complex to practically deploy PBFT. It is worth noting that in some materials the communication complexity of the PBFT protocol is inappropriately attributed to the full connection between n nodes. By changing the fully connected network topology to the P2P network topology based on distributed hash tables commonly used in blockchain projects, high communication complexity caused by full connection can be conveniently solved, yet still, it is difficult to improve the communication complexity during the view conversion process. In recent years, researchers have proposed to reduce the amount of communication in this step by adopting aggregate signature scheme. With this technology, 2f+1 signature information can be compressed into one, thereby reducing the communication volume during view change.
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Proof of Authority

Proof of Authority
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The Blockchain industry is continuously progressing since its inception. The consensus mechanism is the core of a decentralized ecosystem that helps it to achieve consensus in the network. Till now, many consensus methods have been invented and implemented to achieve consensus within a blockchain system. I am writing a series of articles on different consensus mechanisms with a detailed explanation of their advantages and disadvantages over each other. I have already covered PoW and PoS, so here in this article, I will focus on PoA.
The PoW consensus algorithm used by Bitcoin is considered a reliable and secure consensus mechanism but it doesn’t support scalability. As a result, it restricts the performance of the Bitcoin network along with its transaction speed. The major disadvantage of this method is that it requires high energy consumption and system resources which are needed to solve the complex mathematical puzzles.
With some more features, Proof of Stake came into existence which offers better performance than PoW. There are several PoS projects which are still under development so what new features it can offer and how much it can deal with the drawback of the existing consensus mechanism is depends on the success rate of future projects.
Then there is another consensus mechanism called Proof of Authority which is the enhanced version of PoS. It supports better performance by allowing more transactions per second. Now let’s discuss it in detail.
What is Proof of Authority?
The Proof-Of-Authority (PoA) is a consensus method where a group of validators is already chosen as the authority. Their task is to check and validate all the newly added identities, validate transactions, and blocks to add to the network. To ensure efficiency and security in the network the validator group is usually kept small (~25 or less).
Proof of Authority (PoA) is an enhanced version of Proof of Stake (PoS) where the validator’s identity is used as a stake in the network.
A node needs to complete a mandatory process to authenticate itself to receive the right to generate new blocks. Validators need to register themselves in the public notary database using government-issued documents with the same identity that they have on the platform. Thus, Blocks and transactions are verified by participants, whose identity is already verified and acts as an authority of the system.
With the power under a limited number of users, PoA consensus can be adopted as a solution for private networks rather than public blockchains.
PoA was proposed by a group of developers in March 2017 (coined by Gavin Wood) as a blockchain-based on the Ethereum protocol. It was developed with the idea to solve the problem of spam attacks on Ethereum’s Ropsten test network. The new network was named Kovan, the main test network that all Ethereum users use today.
Pre-Requisites for Proof of Authority Consensus
The PoA consensus algorithm is usually based upon the following criteria:
· Validators need to disclose and confirm their identities by giving government-issued documents.
· The standard procedure for verifying the identity of validators.
· Complex and robust criteria to define a validator so that they can put his reputation at stake and commit to a long-term alliance.
Advantages of PoA consensus
As compared to other consensus methods, PoA offers the following advantages:
· High transaction rate.
· High-performance hardware is not required.
· PoA networks are very scalable as compare to PoW blockchains
· Less power extensive.
· Low transaction fees.
· Sequentially block generation with fixed time interval by authorized network nodes. This increases transaction validity speed.
· No communication is required to reach the consensus between the nodes.
· Network operation is independent of the number of available genuine nodes.
· The chance of a node to become a forge depends upon both its stake and overall holding.
Drawback
· Proof-of-Authority based networks lack in decentralization.
· PoA validator's identities are visible in the network.
· PoA does not guarantee censorship resistance.
Practical Implementation
PoA consensus algorithm can be applied in various fields and industries to achieve high throughput ranging from supply chains to banking sectors. PoA is considered as an effective and reasonable solution along with cost-saving benefit.
Below is the list of projects which has adopted PoA :
· Ethereum’s test net Kovan built on the Parity's PoA Protocol
· PoA Network by the Proof of Authority, LLC. (an Ethereum sidechain)
· The VeChainThor platform.
Conclusion
Every consensus method, be it PoW, PoS or PoA has its own set of advantages and disadvantages. But if we talk about PoA particularly, it somehow compromises in the decentralization area to achieve scalability and throughput.
Proof-Of-Authority can, therefore, be treated as a better option for a centralized solution because of its efficiency and less power consumption property.
Read More: Mastering Basic Attention Token (BAT)
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Detailed SHA-256 Algorithm Explanation

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