Difficulty - Bitcoin Wiki

hashflare

Discussion based on cloud mining specifically using HashFlare.
[link]

Primecoin

Discussion about Primecoin and its infra. Primecoin is a very innovative cryptocurrency, being the 1st non Hash-Cash PoW crypto, naturally scarce (not artificially), with very fast confirmations (1min), elastic readjusting reward & a useful mining (byproducts are primes). Primecoin is sustainable (miners are guaranteed to have revenues), and decentralized (ASIC/FPGA are not particularly advantaged). Sidechain for decentralized data applications (e.g. Storj) currently in development.
[link]

QuarkCoin Cryptocurrency

Quark is a decentralized digital monetary system. It facilitates sending Quarks to Friends, Family Members Online Payments free of charges and charge-backs. Military Grade Encryption. No Bank or Government Control. Quark coins are based on the original idea of Bitcoin but improved, more secure, faster transaction times and zero fees. With improvements to design and security. There is also a greater coin supply with higher block rewards for miners. Quark is fully Open Source.
[link]

Welcome to the Official Energi Cryptocurrency Reddit!

Welcome to the Official Energi Cryptocurrency Reddit!

https://preview.redd.it/mymfi39kf2c51.png?width=200&format=png&auto=webp&s=71c90d32c9bf87dbd393e85bbeedb753e202a5b0
Below you will find a Table of Contents that will cover all the fundamentals of the cryptocurrency.

Table of Contents

  1. What is Energi?
  2. What are the Fundamentals of Energi?
    1. Scalability
    2. Funding
    3. Governance
    4. Inflation
    5. Distribution
    6. Decentralization
    7. Long Term Vision
  3. Coin Specs
  4. How to Get Started
    1. Official Energi Website
    2. Social Media
    3. Exchanges
    4. Energi Block Explorers
    5. Wallet Downloads
    6. Proof-of-Stake Setup Guides
    7. Masternode Setup Guide
  5. FAQ

1. What is Energi

Energi is a self-funding (no ICO and no premine) cryptocurrency that has a purpose to become the world’s leading cryptocurrency with the unification of Smart Contracts, Governance and Self-funding Treasury to ensure longevity and enable rapid growth. You can read more about why we decided to self-fund and chose not to conduct an ICO here.
Energi provides a small allocation to Proof-of-Stake (PoS) rewards, takes a bulk of the coin issuance and gives it to its treasury and active Masternodes. Energi also allocates 10% on-going reward to the leadership of the Energi Backbone, which is significantly less compared to today’s ICOs’ rewarding their founders between 20–50% of the tokens distributed. Another trait that sets Energi apart from ICOs is they give an on-going 10% allocation through each block reward, rather than rewarding the founders up-front.

2. What are the Fundamentals of Energi?

  • Scalability
1 minute block times and a 2 megabyte block size limit provide Energi with a vast transaction capacity for regular on-chain transactions. This allows for plenty of space on the blockchain for extremely fast transactions with very low fees.
Energi features a powerful on-chain scaling solution with a system of incentivized full nodes called Energi Masternodes. A Masternode is a full node backed by 1,000 NRG collateral that provides level 2 scalability to the Energi Cryptocurrency. 40% of the emissions of Energi is allocated to Masternodes, providing an extremely strong incentive to grow the number of full nodes and scalability of the network.

  • Funding
A key feature of Energi is its powerful treasury system. Energi makes up to 40% of the emissions available to the treasury, to be utilized in a manner that provides maximum benefit.
Treasury allocation is decentralized, allowing for submitted proposals from anyone, to be voted on by Masternodes and paid out from the emissions.
Energi has a 14 day treasury cycle, allowing quick payments for proposal authors and contributors, as well as strategic responsiveness to effective proposals. Energi is guided by the principle that every dollar spent from its funding model should yield more than one dollar of value in return. Thanks to a 14 day treasury cycle, the Energi team is able to measure results and respond quickly to changes in strategy.

  • Governance
The Energi Treasury is a decentralized governance model designed with Masternodes as caretakers, with voting rights on how to best utilize treasury funding.
This governance model reduces risk by allowing participation from everyone who holds 1,000 NRG as a Masternode. In this way, the Energi community can work together on how to best build the strategic direction of Energi.

  • Inflation
Energi Cryptocurrency has a simple rate of inflation at 1 million coins per month with no maximum cap. This ensures consistency in funding allocation, Masternode rewards, and PoS rewards, making the economics of the cryptocurrency more understandable for everyone who chooses to participate in Energi.
No coin supply limit ensures that Energi is prepared for the long term, avoiding “bubble” economics caused by dramatic early inflation that in most coins only serves to benefit founders ahead of increased adoption.

  • Distribution
Energi conducted a fair launch on April 14, 2018 with no ICO and no premine. Prior to launch, the Energi team gave a specific time and date for the launch of its main net, which its vibrant community eagerly awaited, so that mining could begin fairly, again avoiding centralization among the coin founders (It's important to note that Energi has transitioned from Proof-of-Work consensus to a Proof-of-Stake consensus).
Energi Masternode payments were designed to begin at block 216000, which occurred on September 18, 2018, almost 160 days after launch. This ensured time to list Energi on exchanges, and to grow the community, encouraging fair and equitable distribution before the extremely powerful Masternode rewards began. It is all too common for Masternode coins to feature a premine, which has the effect of centralizing distribution among the founders and early adopters.
From 2018 to 2020, Energi distributed nearly 4 million coins to users who contributed to spreading awareness of the project with social media activities about Energi, such as tweets, follows, and subscriptions on all major social media platforms.

  • Decentralization
Decentralized governance with Masternodes helps to ensure everyone is able to participate in Energi and help guide the project to achieve the best results. The change to the requirement to run a Masternode, from 10 000 NRG to 1 000 NRG, has allowed more people to be involved and boosted decentralization for the whole project.

  • Long Term Vision
All of the above features seamlessly work together in concert, to ensure that Energi is prepared for the long term. Rather than try to closely find a niche in the market, Energi is prepared to adapt and overcome all challenges for many years to come. Energi’s use case is that of a traditional cryptocurrency, such as Bitcoin. However, Energi’s strategy is to excel by avoiding the pitfalls of previous projects, while further utilizing and improving upon the most powerful ideas in the cryptocurrency space.

3. Coin Specs

Ticker: NRG
Block time: 1 minute.
Hashing Algorithm: Dagger-Hashimoto (similar to Ethereum).
Masternode requirements: 1,000 Energi.
Treasury cycle: Every 14 days.
Approximately 1 million Energi will be released per month. The allocations can be observed easily as “10/10/40/40.”
10% will go to the Energi Backbone.
10% to the PoS participants
40% to Masternodes.
40% to the Treasury.
Thus, for every block, allocations are: 2.28 Energi to the Backbone, 2.28 Energi to the PoS participants, 9.14 Energi to the Treasury, and 9.14 Energi to Masternodes.
Since Treasury allocations are paid in two-week cycles, they are made in lump sums of approximately 184,000 Energi every 14 days.
In order to allow for widespread distribution of Energi before Masternode payments began, Masternode rewards were delayed until day 150. This was to allow the airdrop campaign to be completed and ensure a large amount of NRG is spread out through the community. Until that point, Masternode rewards were redirected to the Treasury. Thus for the first 5 months, the Treasury gained approximately 368,000 Energi every two weeks (about 800k Energi per month). The airdrop campaign was designed to release ~4 million Energi to the community.

4. How to Get Started

  • Energi Official Website
https://www.energi.world/

  • Social Media
Bitcointalk: https://bitcointalk.org/index.php?topic=4912743
Discord: https://discordapp.com/invite/sCtgNC3
Facebook: https://www.facebook.com/energicrypto/
Github: https://github.com/energicryptocurrency
LinkedIn: https://www.linkedin.com/company/energi-core/
Medium: https://medium.com/energi
Publish 0x: https://www.publish0x.com/@energi
Reddit: https://www.reddit.com/energicryptocurrency/
Steemit: https://steemit.com/@energi
Telegram: https://t.me/energicrypto
Telegram Announcement: https://t.me/energiannouncements
Twitter: https://twitter.com/Energicrypto
YouTube: https://www.youtube.com/channel/UCCABQly0NNR2j_M_iDpy8mA/

  • Exchanges
DigiFinex: https://www.digifinex.com/trade/BTC/NRG
KuCoin - BTC: https://www.kucoin.com/trade/NRG-BTC
KuCoin - ETH: https://www.kucoin.com/trade/NRG-ETH
HitBTC - BTC: https://hitbtc.com/NRG-to-BTC
BitBNs - INR: https://bitbns.com/trade/#/nrg
Mercatox - BTC: https://mercatox.com/exchange/NRG/BTC
Mercatox - TUSD: https://mercatox.com/exchange/NRG/BTC
Bithumb - BTC: https://www.bithumb.pro/en-us/spot/trade?q=NRG-BTC
Bithumb - USDT: https://www.bithumb.pro/en-us/spot/trade?q=NRG-USDT
Citex - BTC: https://trade.citex.co.ktrade/NRG_BTC
Citex - USDT: https://trade.citex.co.ktrade/NRG_USDT
Beaxy - BTC: https://www.beaxy.com/trading-paiNRG-BTC
CoinAll - USDT: https://www.coinall.com/spot/full#product=nrg_usdt
WhiteBit - BTC: https://whitebit.com/trade/NRG_BTC
HitBTC - BTC: https://hitbtc.com/exchange/NRG-to-BTC

  • Energi Block Explorers
Gen 3 Explorer: https://explorer.energi.network/
Gen 3 Calculator: https://nexus.energi.network/reward-calculator
Gen 2 Explorer: https://explorer.gen2.energi.network/

  • Wallet Downloads
Gen 3 - MyEnergiWallet: https://docs.energi.software/en/downloads/myenergiwallet
Gen 3 - Core Node: https://docs.energi.software/en/downloads/core-node

  • Proof-of-Stake Setup Guides
https://docs.energi.software/en/staking-guide

  • Masternode Setup Guide
https://docs.energi.software/en/Masternode-guide

5. FAQs

Gen 3 Wiki: https://docs.energi.software/en/home
General: https://docs.energi.software/en/faq/general
Core Node Sync: https://docs.energi.software/en/core-node-troubleshoot
Keystore: https://docs.energi.software/en/faq/keystore
Masternode: https://docs.energi.software/en/faq/Masternode
Migration: https://docs.energi.software/en/faq/migration
Security: https://docs.energi.software/en/faq/security
Staking: https://docs.energi.software/en/faq/staking
submitted by energicrypto to energicryptocurrency [link] [comments]

The Best Cryptocurrency Mining Pools in 2020

This review is not sponsored! Neither it is an ad.
How to choose a mining pool? How to avoid stale shares? The pros and cons of different services.

What is a cryptocurrency mining pool?

A “mining pool" is a server that distributes the task of calculating the block signature between all connected participants. The contribution of each of them is evaluated using the so-called “shares”, which are potential candidates for receiving a signature. As soon as one of the “shares” hits the target, the pool announces the readiness of the block and distributes the reward.
However, if you participate in the pool, then you will have to share the profit with all the participants in the pool, but for the majority, this usually is the most profitable option.

Which pool is better for mining?

The best mining pools should meet the following criteria:

Key selection criteria

To select a good pool for each specific cryptocurrency, you need to carefully study all the information available about it on its website and on the forums.
To reduce the number of stale shares, it is better to mine on the pool closest to the miner. You can choose the fastest mining pool by studying the information about the processing speed of the share in the mining program or by pinging the time it takes for the signal to pass from the miner's computer to the servers of the pool.

10 most popular and powerful pools: Description

ViaBTC

Coins: BTC, BCH, BSV, LTC, ETH, ETC, ZEC, DASH, XMR, CKB
Commission: 3%, lifetime discount: 1%

EMCD

Coins: BTC, BSV, BCH, LTC, ETC, ETH, DASH
Commission: 0%. There is a donation option: 0.5% of the income

Ethermine

Coins: ETH, ETC, ZEC
Commission: 1%

F2pool

Coins: BTC, LTC, and many other coins
Commission: 3-5%

NanoPool

Coins: XMR, ETH, ETC, SiaCoin, ZEC, PASC, ETN
Commission:1%

Mining Pool Hub

Coins: BTC, BSV, BCH, LTC
Commission: 0.9%

NiceHash

Coins: BTC, ETH, XRP, BCH, LTC, ZEC, DASH, XLM, EOS, USDT, LINK, BAT, ZRX, HOT, OMG, REP, BTG, NEXO, MATIC, ENJ, SNT, ELF, BNT, KNC, POLY, MTL + 20 more.
Commission: 2-5%

Coinotron

Coins: ETH, ETC, PASC, LTC, Zcash, BTG, DASH, FTC, VTC
Commission: 1-1.5%

Monero Mining Pool

Coins: XMR
Commission: 2%

Baikalmine

Coins: ETH, ETC, MOAC, CLO
Commission: 0.5-1%

Independent Pool Statistics

To make sure that the pools work and really exist, check independent sources. These are:
Keep up with the news of the crypto world at CoinJoy.io Follow us on Twitter and Medium. Subscribe to our YouTube channel. Join our Telegram channel. For any inquiries mail us at [[email protected]](mailto:[email protected]).
submitted by CoinjoyAssistant to dogemining [link] [comments]

CelesOS Research Institute丨DPoW consensus mechanism-combustible mining and voting

CelesOS Research Institute丨DPoW consensus mechanism-combustible mining and voting
The token economy and the blockchain complement each other, while at the same time, the consensus mechanism forms the basis of the blockchain, whom constitutes the basic technical framework of the token economy.
The mainstream blockchain, like Bitcoin, Ethereum, and EOS have all compromised on certain aspects of the "impossible triangle" features.
https://preview.redd.it/8ocq98swpt551.png?width=554&format=png&auto=webp&s=37ab0235c07b450217e22531ad5291d5b4bcbbee
Bitcoin, as a decentralized digital currency, has sacrificed performance to meet the design requirements of decentralization and security, rendering it the target of highest attacking cost among all PoW public chains. The ASIC mining machines updates continually and new versions launch, both can continuously improve the computing power of the entire network.
Ethereum 2.0 will use a proof of stake (PoS) consensus mechanism. On the Ethereum network, money can be transfered and smart contracts can be operated, presenting a more complicated application scenario. However, due to its low performance, Ethereum is more prone to get congested.
EOS, as a blockchain application platform, is often suspected of being centralized. EOS uses a delegated proof of stake (DPoS) consensus mechanism. Having 21 super nodes responsible for bookkeeping and block generation, the EOS main network can handle more than 4,000 TPS now. However, due to its small number of nodes, it’s one of the three major public chains that are most easily questioned by the outside world on the "decentralization" feature.
An inefficient blockchain will only be a game in the laboratory, and an efficient blockchain without decentralization will only be taken advantage of by big players.
New generation consensus algorithm DPoW
Is there any consensus mechanism that can achieve a better balance between decentralization and efficiency, and can give miners incentives to invest in hardware resources? If we separate the two acts of "acquiring accounting rights" and "receiving block rewards", the above dilemma can be solved. By separating the above two, DPoW has finally achieved the effect of balancing efficiency and centralization.

https://preview.redd.it/www3h8swpt551.png?width=731&format=png&auto=webp&s=c0bf49a42751a9501828d0294bc9280f856c441e
Drawing on the design concept and operating experience of the preceding consensus mechanisms, DPoW is a new-generation consensus mechanism formed based on PoB and DPoS.
Before explaining DPoW, it’s necessary to introduce PoB.
PoB (Proof of Burn) is called the burning proof mechanism. (Source: https://en.bitcoin.it/wiki/Proof_of_burn))

https://preview.redd.it/payq2duzpt551.png?width=554&format=png&auto=webp&s=4b8e9181d95d31a8d5b75a7acab27c851a4a3a4d
PoB is a way to vote who has a commitment to the leadership of the network by burning tokens possessed. The greater the number of tokens burned, the higher the probability of gaining network leadership.
PoB is a method of distributed consensus and an alternative method of proof-of-work mechanism. It can also be used to guide a cryptocurrency.

https://preview.redd.it/4lmhs1i1qt551.png?width=554&format=png&auto=webp&s=e8c50b1638d8ec8d8a2dac2e842b50a2979984fb
In the DPoW-based blockchain, the miner's mining reward is no longer a token, but a "wood" that can be burned-burning wood. Through the hash algorithm, miners use their own computing power to get the corresponding non-tradable wood after proving their workload eventually. When the wood has accumulated to a certain amount, it can be burnt in the burning site.
DPoW technical solutions
Voting with computing power is the biggest innovation of the present invention. It uses the proof of work of the PoW algorithm to replace the stakes as votes, yet retains the BFT-DPoS block generation mechanism.
Specific steps are as follow:
  1. POW question acquisition
Obtain the question of proof of work. The proof of work of the present invention is to perform a Hash operation on a PoW problem; the questions is:
target = hash(block_id + account) ^ difficulty 
  1. POW question answering
A mathematical hash operation of a random number (nonce) is performed on the question, and if the hash value obtained is less than a certain value, the question is answered;
Question answering process:
nonce = random ()ret = max() while(ret > target) { if(hash(nonce+account + block_id)< target) { wood = nonce; break; } nonce++; } 
  1. Voting
Voting is to cast the specific answers to the question to the candidate BP. By such, it’s submitted to the blockchain and counted to the blockchain's status database; within an election period, the maximum value of the answer that each voter can calculate is N, and each answer can only be voted to one candidate BP, and the number of votes that can be cast is N.
The information and process that voting requires:
  • Answer to the question
  • Miner account
  • Block id
  • Block
  • Voting objects (candidate BP)
  • Verify that the vote is valid
  • After verification, it will be credited to BP
4. Count the votes
At the end of an election period, votes are counted and sorted top-down according to the number of votes under the name of the candidate BP. The top X candidate BPs are selected and inserted into the BP list, and the block generating order of the selected BP is written to the blockchain status database.
If X is the number of BPs generated by the system, namely a multiple of 3, it will be set in the genesis block and cannot be changed.
  1. Block generation
The DPoW block generation mechanism is the same as BFT-DPoS. The elected BP negotiates a block generation ownership order based on its own network resource status. When each BP node has block generation rights, the block reward is a fixed reward for each effective irreversible block. At the same time, the blocks that have been generated use the BFT signature mechanism. After getting 2/3 BP's signature, the block will become an irreversible block.
DPoW’s advantage in balance
Compared with existing technical solutions, the DPoW consensus protocol has the following feature.
  1. When the stock of burning wood is large, the nodes in the system tend to burn burning wood to vote instead of logging through computing power, which is similar to the DPoS under this situation.
  2. When the stock of burning wood is few, the nodes in this system tend to log to obtain burning wood for voting, which is similar to PoW under this situation, presenting the feature of decentralization. In order to ensure the high-speed operation of the system and attract ticket sources, BP will maintain a stable investment in computer resources to keep the system highly efficient.
Choosing to vote by logging or burning wood depends on the nodes’ own optimal choice, resulting in constant choosing between the two consensus mechanisms of PoW and DPoS. This will make nodes tend to choose PoW when decentralization is needed, and to choose DPoS when efficiency is needed.
For a system, whether it is decentralized does not depend on whether each block needs to be decentralized. The key is whether the system can provide a channel to decentralization and fair competition when needed. As long as the channel is reasonable, the system will be considered decentralized.
By decoupling vote by logging and block generation, they can be done asynchronously to achieve the effects of decentralization and high efficiency.
Learning and updating the preceding practices in blockchain technology, DPoW manages to achieve both decentralization and efficiency, as “having the cake and eating it”.

📷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
submitted by CelesOS to u/CelesOS [link] [comments]

The Best Cryptocurrency Mining Pools in 2020

This review is not sponsored! Neither it is an ad.
How to choose a mining pool? How to avoid stale shares? The pros and cons of different services.

What is a cryptocurrency mining pool?

A “mining pool" is a server that distributes the task of calculating the block signature between all connected participants. The contribution of each of them is evaluated using the so-called “shares”, which are potential candidates for receiving a signature. As soon as one of the “shares” hits the target, the pool announces the readiness of the block and distributes the reward.
However, if you participate in the pool, then you will have to share the profit with all the participants in the pool, but for the majority, this usually is the most profitable option.

Which pool is better for mining?

The best mining pools should meet the following criteria:

Key selection criteria

To select a good pool for each specific cryptocurrency, you need to carefully study all the information available about it on its website and on the forums.
To reduce the number of stale shares, it is better to mine on the pool closest to the miner. You can choose the fastest mining pool by studying the information about the processing speed of the share in the mining program or by pinging the time it takes for the signal to pass from the miner's computer to the servers of the pool.

10 most popular and powerful pools: Description

ViaBTC

Coins: BTC, BCH, BSV, LTC, ETH, ETC, ZEC, DASH, XMR, CKB
Commission: 3%, lifetime discount: 1%

EMCD

Coins: BTC, BSV, BCH, LTC, ETC, ETH, DASH
Commission: 0%. There is a donation option: 0.5% of the income

Ethermine

Coins: ETH, ETC, ZEC
Commission: 1%

F2pool

Coins: BTC, LTC, and many other coins
Commission: 3-5%

NanoPool

Coins: XMR, ETH, ETC, SiaCoin, ZEC, PASC, ETN
Commission:1%

Mining Pool Hub

Coins: BTC, BSV, BCH, LTC
Commission: 0.9%

NiceHash

Coins: BTC, ETH, XRP, BCH, LTC, ZEC, DASH, XLM, EOS, USDT, LINK, BAT, ZRX, HOT, OMG, REP, BTG, NEXO, MATIC, ENJ, SNT, ELF, BNT, KNC, POLY, MTL + 20 more.
Commission: 2-5%

Coinotron

Coins: ETH, ETC, PASC, LTC, Zcash, BTG, DASH, FTC, VTC
Commission: 1-1.5%

Monero Mining Pool

Coins: XMR
Commission: 2%

Baikalmine

Coins: ETH, ETC, MOAC, CLO
Commission: 0.5-1%

Independent Pool Statistics

To make sure that the pools work and really exist, check independent sources. These are:
Keep up with the news of the crypto world at CoinJoy.io Follow us on Twitter and Medium. Subscribe to our YouTube channel. Join our Telegram channel. For any inquiries mail us at [[email protected]](mailto:[email protected]).
submitted by CoinjoyAssistant to MiningPoolHub [link] [comments]

Proof Of Work Explained

Proof Of Work Explained
https://preview.redd.it/hl80wdx61j451.png?width=1200&format=png&auto=webp&s=c80b21c53ae45c6f7d618f097bc705a1d8aaa88f
A proof-of-work (PoW) system (or protocol, or function) is a consensus mechanism that was first invented by Cynthia Dwork and Moni Naor as presented in a 1993 journal article. In 1999, it was officially adopted in a paper by Markus Jakobsson and Ari Juels and they named it as "proof of work".
It was developed as a way to prevent denial of service attacks and other service abuse (such as spam on a network). This is the most widely used consensus algorithm being used by many cryptocurrencies such as Bitcoin and Ethereum.
How does it work?
In this method, a group of users competes against each other to find the solution to a complex mathematical puzzle. Any user who successfully finds the solution would then broadcast the block to the network for verifications. Once the users verified the solution, the block then moves to confirm the state.
The blockchain network consists of numerous sets of decentralized nodes. These nodes act as admin or miners which are responsible for adding new blocks into the blockchain. The miner instantly and randomly selects a number which is combined with the data present in the block. To find a correct solution, the miners need to select a valid random number so that the newly generated block can be added to the main chain. It pays a reward to the miner node for finding the solution.
The block then passed through a hash function to generate output which matches all input/output criteria. Once the result is found, other nodes in the network verify and validate the outcome. Every new block holds the hash of the preceding block. This forms a chain of blocks. Together, they store information within the network. Changing a block requires a new block containing the same predecessor. It is almost impossible to regenerate all successors and change their data. This protects the blockchain from tampering.
What is Hash Function?
A hash function is a function that is used to map data of any length to some fixed-size values. The result or outcome of a hash function is known as hash values, hash codes, digests, or simply hashes.
https://preview.redd.it/011tfl8c1j451.png?width=851&format=png&auto=webp&s=ca9c2adecbc0b14129a9b2eea3c2f0fd596edd29
The hash method is quite secure, any slight change in input will result in a different output, which further results in discarded by network participants. The hash function generates the same length of output data to that of input data. It is a one-way function i.e the function cannot be reversed to get the original data back. One can only perform checks to validate the output data with the original data.
Implementations
Nowadays, Proof-of-Work is been used in a lot of cryptocurrencies. But it was first implemented in Bitcoin after which it becomes so popular that it was adopted by several other cryptocurrencies. Bitcoin uses the puzzle Hashcash, the complexity of a puzzle is based upon the total power of the network. On average, it took approximately 10 min to block formation. Litecoin, a Bitcoin-based cryptocurrency is having a similar system. Ethereum also implemented this same protocol.
Types of PoW
Proof-of-work protocols can be categorized into two parts:-
· Challenge-response
This protocol creates a direct link between the requester (client) and the provider (server).
In this method, the requester needs to find the solution to a challenge that the server has given. The solution is then validated by the provider for authentication.
The provider chooses the challenge on the spot. Hence, its difficulty can be adapted to its current load. If the challenge-response protocol has a known solution or is known to exist within a bounded search space, then the work on the requester side may be bounded.
https://preview.redd.it/ij967dof1j451.png?width=737&format=png&auto=webp&s=12670c2124fc27b0f988bb4a1daa66baf99b4e27
Source-wiki
· Solution–verification
These protocols do not have any such prior link between the sender and the receiver. The client, self-imposed a problem and solve it. It then sends the solution to the server to check both the problem choice and the outcome. Like Hashcash these schemes are also based on unbounded probabilistic iterative procedures.
https://preview.redd.it/gfobj9xg1j451.png?width=740&format=png&auto=webp&s=2291fd6b87e84395f8a4364267f16f577b5f1832
Source-wiki
These two methods generally based on the following three techniques:-
CPU-bound
This technique depends upon the speed of the processor. The higher the processor power greater will be the computation.
Memory-bound
This technique utilizes the main memory accesses (either latency or bandwidth) in computation speed.
Network-bound
In this technique, the client must perform a few computations and wait to receive some tokens from remote servers.
List of proof-of-work functions
Here is a list of known proof-of-work functions:-
o Integer square root modulo a large prime
o Weaken Fiat–Shamir signatures`2
o Ong–Schnorr–Shamir signature is broken by Pollard
o Partial hash inversion
o Hash sequences
o Puzzles
o Diffie–Hellman–based puzzle
o Moderate
o Mbound
o Hokkaido
o Cuckoo Cycle
o Merkle tree-based
o Guided tour puzzle protocol
A successful attack on a blockchain network requires a lot of computational power and a lot of time to do the calculations. Proof of Work makes hacks inefficient since the cost incurred would be greater than the potential rewards for attacking the network. Miners are also incentivized not to cheat.
It is still considered as one of the most popular methods of reaching consensus in blockchains. Though it may not be the most efficient solution due to high energy extensive usage. But this is why it guarantees the security of the network.
Due to Proof of work, it is quite impossible to alter any aspect of the blockchain, since any such changes would require re-mining all those subsequent blocks. It is also difficult for a user to take control over the network computing power since the process requires high energy thus making these hash functions expensive.
submitted by RumaDas to u/RumaDas [link] [comments]

Calculate txn_id from raw txn_hex

I'm trying to calculate a txn_id from raw txn_hex. The procedure works fine for legacy TXNs but gets non-expected results on Segwit TXNs. I compared this snippet of code to what txn_id was produced by Electrum and the blockchain.com TXN decoder:
  1. Take in TXN in hex
  2. Convert the hex to binarray
  3. Double hash binarray
  4. Reverse the resultant digest because of endianness
  5. Display in hex.
t0 is my legacy testnet TXN and t1 is my segwit testnet TXN.
Thoughts?

UPDATE

Found the relevant source in Electrum transaction.py:1036
Basically you strip the flags and tx_witnesses listed in the wiki spec
```python

!/usbin/env python3

[repo] https://github.com/brianddk/reddit ... python/txn_hash.py

[ref] https://www.reddit.com/g4hvyf

from hashlib import sha256
def txid(tx): bin = bytes.fromhex(tx) txid = sha256(sha256(bin).digest()).digest()[::-1].hex() return txid

Raw Legacy

t0 = ('0200000001cd3b93f5b24ae190ce5141235091cd93fbb2908e24e5b9ff6776ae' 'c11b0e04e5000000006b4830450221009f156db3585c19fe8e294578edbf5b5e' '4159a7afc3a7a00ebaab080dc25ecb9702202581f8ae41d7ade2f06c9bb9869e' '42e9091bafe39290820438b97931dab61e140121030e669acac1f280d1ddf441' 'cd2ba5e97417bf2689e4bbec86df4f831bf9f7ffd0fdffffff010005d9010000' '00001976a91485eb47fe98f349065d6f044e27a4ac541af79ee288ac00000000')

Raw Segwit

t1 = ('0200000000010100ff121dd31ead0f06e3014d9192be8485afd6459e36b09179' 'd8c372c1c494e20000000000fdffffff013ba3bf070000000017a914051877a0' 'cc43165e48975c1e62bdef3b6c942a38870247304402205644234fa352d1ddbe' 'c754c863638d2c26abb9381966358ace8ad7c52dda4250022074d8501460f4e4' 'f5ca9788e60afafa1e1bcbf93e51529defa48317ad83e069dd012103adc58245' 'cf28406af0ef5cc24b8afba7f1be6c72f279b642d85c48798685f86200000000')

UPDATE Raw Segwit with flags and tx_witnesses stripped

t2 = ('02000000' '0100ff121dd31ead0f06e3014d9192be8485afd6459e36b09179' 'd8c372c1c494e20000000000fdffffff013ba3bf070000000017a914051877a0' 'cc43165e48975c1e62bdef3b6c942a3887' '00000000')
print(f"t0: {txid(t0)}\nt1: {txid(t1)}\nt2: {txid(t2)}")

TXN_IDs from the above python

t0: cb33472bcaed59c66fae30d7802b6ea2ca97dc33c6aad76ce2e553b1b4a4e017

t1: b11fdde7e3e635c7f15863a9399cca42d46b5a42d87f4e779dfd4806af2401ce

t2: d360581ee248be29da9636b3d2e9470d8852de1afcf3c3644770c1005d415b30

TXN_IDs from Electrum

t0: cb33472bcaed59c66fae30d7802b6ea2ca97dc33c6aad76ce2e553b1b4a4e017

t1: d360581ee248be29da9636b3d2e9470d8852de1afcf3c3644770c1005d415b30

```
submitted by brianddk to Bitcoin [link] [comments]

Update TKEYSPACE 1.3.0 on Android

Update TKEYSPACE 1.3.0 on Android

https://preview.redd.it/6w93e0afttx41.png?width=1400&format=png&auto=webp&s=c00989612ec2d52eb522405e6b6a98bf875e08bb
Version 1.3.0 is a powerful update to TkeySpace that our team has been carefully preparing. since version 1.2.0, we have been laying the foundation for implementing new features that are already available in the current version.
Who cares about the security and privacy of their assets is an update for you.
TkeySpace — was designed to give You full control over your digital assets while maintaining an exceptional level of security, which is why there is no personal data in the wallet: phone number, the email address that could be compromised by hackers — no identity checks and other hassles, just securely save the backup phrase consisting of 12 words.

Briefly about the TkeySpace 1.3.0 update :

  • Code optimization and switching to AndroidX;
  • New section-Privacy;
  • Built-in TOR;
  • Selecting the privacy mode;
  • Selecting the recovery method for each currency;
  • Choosing the address format for Litecoin;
  • Enhanced validation of transactions and blocks in the network;
  • Disk space optimization;
  • Accelerated syncing;
  • Checking “double spending”;
  • The bloom filter to check for nodes;
  • Updating the Binance and Ethereum libraries;
  • A function to hide the balance;
  • Advanced currency charts;
  • Access to charts without authentication;
  • News section;
  • Browser for Tkeycoin;
  • Independent Commission entry for Bitcoin;
  • New digital currencies;
  • Digital currency exchange tab.

Code optimization and switching to AndroidX

A lot of work has been done on optimizing the code to speed up the application, improving the logic, synchronization speed, calculating the hash of cryptocurrencies, and successfully switching to AndroidX.

https://preview.redd.it/h3go5tzgttx41.png?width=1100&format=png&auto=webp&s=bf311efc73e3577c80f06a21d6b9317bb93ae989

New section: Privacy

  • Enable Tor;
  • Blockchain transaction (the selection of the privacy mode);
  • Blockchain recovery (choosing a recovery method);
https://preview.redd.it/iydfwuhittx41.png?width=1080&format=png&auto=webp&s=2ce7c489d893a2ab6b9d6fede57d8b94404edcfb

TOR

Starting with the current update, the TkeySpace wallet can communicate via the TOR network, includes new privacy algorithms, and supports 59 different currencies.

https://i.redd.it/kn5waeskttx41.gif
Tor is a powerful privacy feature for those who own large assets or live in places where the Internet is heavily censored.
Tor technology provides protection against traffic analysis mechanisms that compromise not only Internet privacy, but also the confidentiality of trade secrets, business contacts, and communications in General.
When you enable TOR settings, all outgoing traffic from the wallet will be encrypted and routed through an anonymous network of servers, periodically forming a chain through the Tor network, which uses multi-level encryption, effectively hiding any information about the sender: location, IP address, and other data.
This means that if your provider blocks the connection, you can rest easy — after all, by running this function, you will get an encrypted connection to the network without restrictions.

https://preview.redd.it/w9y3ax4mttx41.png?width=960&format=png&auto=webp&s=972e375fc26d479e8b8d2999f7659ec332e2af55
In TOR mode, the wallet may work noticeably slower and in some cases, there may be problems with the network, due to encryption, some blockchain browsers may temporarily not work. However, TOR encryption is very important when Internet providers completely block traffic and switching to this mode, you get complete freedom and no blocks for transactions.

Confidentiality of transactions (the Blockchain transaction)

The wallet can change the model of a standard transaction, mixing inputs and outputs, making it difficult to identify certain cryptocurrencies. In the current update, you can select one of several modes for the transaction privacy level: deterministic lexicographic sorting or shuffle mode.

Mode: Lexicographic indexing

Implemented deterministic lexicographic sorting using hashes of previous transactions and output indexes for sorting transaction input data, as well as values and scriptPubKeys for sorting transaction output data;
We understand that information must remain confidential not only in the interests of consumers but also in higher orders, financial systems must be kept secret to prevent fraud. One way to address these privacy shortcomings is to randomize the order of inputs and outputs.
Lexicographic ordering is a comparison algorithm used to sort two sets based on their Cartesian order within their common superset. Lexicographic order is also often referred to as alphabetical order or dictionary order. The hashes of previous transactions (in reverse byte order) are sorted in ascending order, lexicographically.
In the case of two matching transaction hashes, the corresponding previous output indexes will be compared by their integer value in ascending order. If the previous output indexes match, the input data is considered equal.

Shuffle Mode: mixing (random indexing)

To learn more about how “shuffle mode” works, we will first analyze the mechanisms using the example of a classic transaction. Current balance Of your wallet: 100 TKEY, coins are stored at different addresses:
x1. Address-contains 10 TKEY. x2. Address-contains 20 TKEY. x3. Address-contains 30 TKEY. x4. Address-contains 15 TKEY. x5. Address-contains 25 TKEY.
Addresses in the blockchain are identifiers that you use to send cryptocurrency to another person or to receive digital currency.
In a classic transaction, if you need to send, for example, 19 TKEY — 100 TKEY will be sent to the network for “melting” coins, 19 TKEY will be sent to the Recipient, and ~80.9 TKEY will return to the newly generated address for “change” in your wallet.

https://preview.redd.it/x595qwdottx41.png?width=806&format=png&auto=webp&s=d9c2ae5620a3410ed83f7e16c018165c8ab35844
In the blockchain explorer, you will see the transaction amount in the amount of 100 TKEY, where 80.99999679 TKEY is your change, 19 TKEY is the amount you sent and 0.00000321 is the transaction fee. Thus, in the blockchain search engine, most of your balance is shown in the transaction.

How does the shuffle mode work?

Let’s look at a similar example: you have 100 TKEY on your balance, and you need to send 19 TKEY.
x1. Address-contains 10 TKEY. x2. Address-contains 20 TKEY. x3. Address-contains 30 TKEY. x4. Address-contains 15 TKEY. x5. Address-contains 25 TKEY.
You send 19 TKEY, the system analyzes all your addresses and balances on them and selects the most suitable ones for the transaction. To send 19 TKEY, the miners will be given coins with x2. Addresses, for a total of 20 TKEY. Of these, 19 TKEY will be sent to the recipient, and 0.99999679 TKEY will be returned to Your new address as change minus the transaction fee.

https://preview.redd.it/doxmqffqttx41.png?width=1400&format=png&auto=webp&s=5c99ec41363fe50cd651dc0acab05e175416006a
In the blockchain explorer, you will see the transaction amount in the amount of 20 TKEY, where 0.99999679 TKEY is Your change, 19 TKEY is the amount you sent and 0.00000321 is the transaction fee.
The shuffle mode has a cumulative effect. with each new transaction, delivery Addresses will be created and the selection of debit addresses/s that are most suitable for the transaction will change. Thus, if you store 1,000,000 TKEY in your wallet and want to send 1 TKEY to the recipient, the transaction amount will not display most of your balance but will select 1 or more addresses for the transaction.

Selecting the recovery method for each digital currency (Blockchain restore)

Now you can choose the recovery method for each currency: API + Blockchain or blockchain.
Note: This is not a syncing process, but rather the choice of a recovery method for your wallet. Syncing takes place with the blockchain — regardless of the method you choose.
https://preview.redd.it/gxsssuxrttx41.png?width=1080&format=png&auto=webp&s=cd9fe383618dda0e990e86485652ff95652a8481

What are the differences between recovery methods?

API + Blockchain

In order not to load the entire history of the blockchain, i.e. block and transaction headers, the API helps you quickly get point information about previous transactions. For example, If your transactions are located in block 67325 and block 71775, the API will indicate to the node the necessary points for restoring Your balance, which will speed up the “recovery” process.
As soon as the information is received, communication with the peers takes place and synchronization begins from the control point, then from this moment, all subsequent block loading is carried out through the blockchain. This method allows you to quickly restore Your existing wallet.
‘’+’’ Speed.
‘’-’’ The API server may fail.

Blockchain

This method loads all block headers (block headers + Merkle) starting from the BIP44 checkpoint and manually validates transactions.
‘’+’’ It always works and is decentralized. ‘’-’’ Loading the entire blockchain may take a long time.

Why do I need to switch the recovery method?

If when creating a wallet or restoring it, a notification (!) lights up in red near the selected cryptocurrency, then most likely the API has failed, so go to SettingsSecurity CenterPrivacyBlockchain Restore — switch to Blockchain. Syncing will be successful.

Selecting the address format

You can choose the address format not only for Bitcoin but also for Litecoin. Legacy, SegWit, Native SegWit. Go to SettingsManage WalletsAddress Format.

https://preview.redd.it/nqj0nwutttx41.png?width=1080&format=png&auto=webp&s=fc04b8ee8339ab27d3203ff551013cda7aa9e8db

Working at the code level

Enhanced validation of transactions and blocks in the network

Due to the increased complexity in the Tkeycoin network, we have implemented enhanced validation of the tkeycoin consensus algorithm, and this algorithm is also available for other cryptocurrencies.

What is the advantage of the enhanced validation algorithm for the user

First, the name itself speaks for itself — it increases the security of the network, and second, by implementing the function — we have accelerated the work of the TkeySpace blockchain node, the application consumes even fewer resources than before.
High complexity is converted to 3 bytes, which ensures fast code processing and the least resource consumption on your device.

Synchronization

The synchronization process has been upgraded. Node addresses are added to the local storage, and instant synchronization with nodes occurs when you log in again.

Checking for double-spending

TkeySpace eliminates “double-spending” in blockchains, which is very valuable in the Bitcoin and Litecoin networks.
For example, using another application, you may be sent a fake transaction, and the funds will eventually disappear from the network and your wallet because this feature is almost absent in most applications.
Using TkeySpace — you are 100% sure that your funds are safe and protected from fraudulent transactions in the form of “fake” transactions.

The bloom filter to check for nodes

All nodes are checked through the bloom filter. This allows you to exclude fraudulent nodes that try to connect to the network as real nodes of a particular blockchain.
In practice, this verification is not available in applications, Tkeycoin — decided to follow a new trend and change the stereotypes, so new features such as node verification using the bloom filter and double-spending verification are a kind of innovation in applications that work with cryptocurrencies.

Updating the Binance and Ethereum libraries

Updated Binance and Ethereum libraries for interaction with the TOR network.

Interface

Function — to hide the balance

This function allows you to hide the entire balance from the main screen.

Advanced currency charts and charts without authentication

Detailed market statistics are available, including volumes, both for 1 day and several years. Select the period of interest: 1 day, 7 days, 1 month, 3 months, 6 months, 1 year, 2 years.
In version 1.3.0, you can access charts without authentication. You can monitor the cryptocurrency exchange rate without even logging in to the app. If you have a pin code for logging in, when you open the app, swipe to the left and you will see a list of currencies.

https://preview.redd.it/f3thqv1wttx41.png?width=1080&format=png&auto=webp&s=1906307f7ad1fd6db47bf270ce7c57185267b1a3

News

In the market data section — in the tkeyspace added a section with current news of the cryptocurrency market.

https://preview.redd.it/lz1e7ynxttx41.png?width=1080&format=png&auto=webp&s=b6f1858d8752cfc6187df5d7b8a2ce25813e2366

Blockchain Explorer for Tkeycoin

Transaction verification for Tkeycoin is now available directly in the app.

Independent Commission entry for Bitcoin

Taking into account the large volume of the Bitcoin network, we have implemented independent Commission entry — you can specify any Commission amount.
For other currencies, smart Commission calculation is enabled based on data from the network. The network independently regulates the most profitable Commission for the sender.

New digital currencies

The TkeySpace wallet supports +59 cryptocurrencies and tokens.

Cryptocurrencies

Tkeycoin (TKEY), Bitcoin (BTC), Litecoin (LTC), Ethereum (ETH), Bitcoin Cash (BCH), DASH, Binance (BNB), EOS.

Stablecoins

TrueUSD (TUSD), Tether USD (USDT), USD Coin (USDC), Gemini Dollar (GUSD), STASIS EURO (EURS), Digix Gold Token (DGX), Paxos Standard (PAX), PAX Gold (PAXG), Binance USD (BUSD), EOSDT, Prospectors Gold (PGL).

ERC-20, BEP2, and EOS tokens

Newdex (NDX), DigixDAO ERC-20 (DGD), Chainlink ERC-20 (LINK), Decentraland ERC-20 (MANA), EnjinCoin ERC-20 (ENJ), the Native Utility (NUT), 0x Protocol ERC-20 (ZRX), Aelf ERC-20 (ELF), Dawn DAO ERC-20 (AURA), Cashaaa BEP2 (CAS), Bancor ERC-20 (BNT), the Basic Attention Token ERC-20 (BAT), Golem ERC-20 (GNT), Mithril ERC-20 (MITH), MEETONE, NEXO ERC-20, Holo ERC-20 (HOT), Huobi Token ERC-20 (HT), IDEX ERC-20, IDEX Membership ERC-20 (IDXM), Bitcoin BEP2 (BTCB), Waltonchain ERC-20 (WTC), KuCoin Shares ERC-20 (KCS), Kyber Network Crystal ERC-20 (KNC), Loom Network ERC-20 (LOOM), Ripple (XRP), Everipedia (IQ), Loopring ERC-20 (LRC), Maker ERC-20 (MKR), the Status of the ERC-20 (SNT), Ankr Network BEP2 (ANKR), OmiseGO ERC-20 (OMG), ^ american English ERC-20 (^american English), Polymath ERC-20 (POLY), Populous ERC-20 (PPT), Pundi X ERC-20 (NPXS), Parser ERC-20 (REP), Revain ERC-20 (R), Binance ERC20 (BNB-ERC20), Gifto BEP2 (GTO).

Exchange of cryptocurrency

The “Limitless Crypto Exchange” tab is available for a quick transition to an unlimited exchange in 200 digital currencies — 10,000 currency pairs.

How do I update TkeySpace to version 1.3.0?

  1. Go to Google Play on your device — My apps and games — find TkeySpace in the list of apps — click Update.
  2. Go to Google Play on your device-write TkeySpace in the search — click on the app icon — Update.
After the update, you will need to restore your wallet.
submitted by tkeycoin to Tkeycoin_Official [link] [comments]

⟳ 870 apps added, 78 updated at f-droid.org

Notice: this update is spurious, and the issue is being looked at.
⟳ f-droid.org from Wed, 26 Feb 2020 20:21:50 GMT updated on Sun, 01 Mar 2020 05:23:29 GMT contains 2962 apps.
Added (870)
Updated (78)
2020-03-01T05:53:18Z
submitted by BrainstormBot to FDroidUpdates [link] [comments]

How to Create Your Own Cryptocurrency Using Python 2020

A blockchain is a public database that irreversibly documents and authenticates the possession and transmission of digital assets. Digital currencies, like Bitcoin and Ethereum, are based on this concept. Blockchain is an exciting technology that you can use to transform the capabilities of your applications.
Of late, we’ve been seeing governments, organizations, and individuals using the blockchain technology to create their own cryptocurrencies—and avoid being left behind. Notably, when Facebook proposed its own cryptocurrency, called Libra, the announcement stirred many waters across the world.

What if you could also follow suit and create your own version of a cryptocurrency?

I thought about this and decided to develop an algorithm that creates a crypto.
I decided to call the cryptocurrency fccCoin.
In this tutorial, I’m going to illustrate the step-by-step process I used to build the digital currency (I used the object-oriented concepts of the Python programming language).
Here is the basic blueprint of the blockchain algorithm for creating the fccCoin:
class Block: def __init__(): #first block class pass def calculate_hash(): #calculates the cryptographic hash of every block class BlockChain: def __init__(self): # constructor method pass def construct_genesis(self): # constructs the initial block pass def construct_block(self, proof_no, prev_hash): # constructs a new block and adds it to the chain pass u/staticmethod def check_validity(): # checks whether the blockchain is valid pass def new_data(self, sender, recipient, quantity): # adds a new transaction to the data of the transactions pass u/staticmethod def construct_proof_of_work(prev_proof): # protects the blockchain from attack pass u/property def last_block(self): # returns the last block in the chain return self.chain[-1]
Now, let me explain what is taking place…
1. Building the first Block class A blockchain comprises of several blocks that are joined to each other (that sounds familiar, right?).
The chaining of blocks takes place such that if one block is tampered with, the rest of the chain becomes invalid.
In applying the above concept, I created the following initial block class
import hashlib import time class Block: def __init__(self, index, proof_no, prev_hash, data, timestamp=None): self.index = index self.proof_no = proof_no self.prev_hash = prev_hash self.data = data self.timestamp = timestamp or time.time() u/property def calculate_hash(self): block_of_string = “{}{}{}{}{}”.format(self.index, self.proof_no, self.prev_hash, self.data, self.timestamp) return hashlib.sha256(block_of_string.encode()).hexdigest() def __repr__(self): return “{} – {} – {} – {} – {}”.format(self.index, self.proof_no, self.prev_hash, self.data, self.timestamp)
As you can see from the code above, I defined the __init__() function, which will be executed when the Block class is being initiated, just like in any other Python class.
I provided the following parameters to the initiation function:
self—this refers to the instance of the Block class, making it possible to access the methods and attributes associated with the class; index—this keeps track of the position of the block within the blockchain; proof_no—this is the number produced during the creation of a new block (called mining); prev_hash—this refers to the hash of the previous block within the chain; data—this gives a record of all transactions completed, such as the quantity bought; timestamp—this places a timestamp for the transactions. The second method in the class, calculate_hash, will generate the hash of the blocks using the above values. The SHA-256 module is imported into the project to assist in obtaining the hashes of the blocks.
After the values have been inputted into the cryptographic hash algorithm, the function will return a 256-bit string representing the contents of the block.
This is how security is achieved in blockchains—every block will have a hash and that hash will rely on the hash of the previous block.
As such, if someone tries to compromise any block in the chain, the other blocks will have invalid hashes, leading to disruption of the entire blockchain network.
Ultimately, a block will look like this:
{ “index”: 2, “proof”: 21, “prev_hash”: “6e27587e8a27d6fe376d4fd9b4edc96c8890346579e5cbf558252b24a8257823”, “transactions”: [ {‘sender’: ‘0’, ‘recipient’: ‘Quincy Larson’, ‘quantity’: 1} ], “timestamp”: 1521646442.4096143 }
2. Building the Blockchain class The main idea of a blockchain, just as the name implies, involves “chaining” several blocks to one another.
Therefore, I’m going to construct a Blockchain class that will be useful in managing the workings of the whole chain. This is where most of the action is going to take place.
The Blockchain class will have various helper methods for completing various tasks in the blockchain.
Let me explain the role of each of the methods in the class.
a. Constructor method This method ensures the blockchain is instantiated.
class BlockChain: def __init__(self): self.chain = [] self.current_data = [] self.nodes = set() self.construct_genesis()
Here are the roles of its attributes:
b. Constructing the genesis block The blockchain requires a construct_genesis method to build the initial block in the chain. In the blockchain convention, this block is special because it symbolizes the start of the blockchain.
In this case, let’s construct it by simply passing some default values to the construct_block method.
I gave both proof_no and prev_hash a value of zero, although you can provide any value you want.
def construct_genesis(self): self.construct_block(proof_no=0, prev_hash=0) def construct_block(self, proof_no, prev_hash): block = Block( index=len(self.chain), proof_no=proof_no, prev_hash=prev_hash, data=self.current_data) self.current_data = [] self.chain.append(block) return block
c. Constructing new blocks
The construct_block method is used for creating new blocks in the blockchain.
Here is what is taking place with the various attributes of this method:
d. Checking validity
The check_validity method is important in assessing the integrity of the blockchain and ensuring anomalies are absent.
As mentioned earlier, hashes are essential for the security of the blockchain as even the slightest change in the object will lead to the generation of a completely new hash.
Therefore, this check_validity method uses if statements to check whether the hash of every block is correct.
It also verifies if every block points to the right previous block, through comparing the value of their hashes. If everything is correct, it returns true; otherwise, it returns false.
u/staticmethod def check_validity(block, prev_block): if prev_block.index + 1 != block.index: return False elif prev_block.calculate_hash != block.prev_hash: return False elif not BlockChain.verifying_proof(block.proof_no, prev_block.proof_no): return False elif block.timestamp <= prev_block.timestamp: return False return True
e. Adding data of transactions
The new_data method is used for adding the data of transactions to a block. It’s a very simple method: it accepts three parameters (sender’s details, receiver’s details, and quantity) and append the transaction data to self.current_data list.
Anytime a new block is created, this list is allocated to that block and reset once more as explained in the construct_block method.
Once the transaction data has been added to the list, the index of the next block to be created is returned.
This index is calculated by adding 1 to the index of the current block (which is the last in the blockchain). The data will assist a user in submitting the transaction in future.
def new_data(self, sender, recipient, quantity): self.current_data.append({ ‘sender’: sender, ‘recipient’: recipient, ‘quantity’: quantity }) return True
f. Adding proof of work
Proof of work is a concept that prevents the blockchain from abuse. Simply, its objective is to identify a number that solves a problem after a certain amount of computing work is done.
If the difficulty level of identifying the number is high, it discourages spamming and tampering with the blockchain.
In this case, we’ll use a simple algorithm that discourages people from mining blocks or creating blocks easily.
u/staticmethod def proof_of_work(last_proof): ”’this simple algorithm identifies a number f’ such that hash(ff’) contain 4 leading zeroes f is the previous f’ f’ is the new proof ”’ proof_no = 0 while BlockChain.verifying_proof(proof_no, last_proof) is False: proof_no += 1 return proof_no u/staticmethod def verifying_proof(last_proof, proof): #verifying the proof: does hash(last_proof, proof) contain 4 leading zeroes? guess = f'{last_proof}{proof}’.encode() guess_hash = hashlib.sha256(guess).hexdigest() return guess_hash[:4] == “0000”
g. Getting the last block
Lastly, the latest_block method is a helper method that assists in obtaining the last block in the blockchain. Remember that the last block is actually the current block in the chain.
u/property def latest_block(self): return self.chain[-1]
Let’s sum everything together
Here is the entire code for creating the fccCoin cryptocurrency.
You can also get the code on this GitHub repository.
import hashlib import time class Block: def __init__(self, index, proof_no, prev_hash, data, timestamp=None): self.index = index self.proof_no = proof_no self.prev_hash = prev_hash self.data = data self.timestamp = timestamp or time.time() u/property def calculate_hash(self): block_of_string = “{}{}{}{}{}”.format(self.index, self.proof_no, self.prev_hash, self.data, self.timestamp) return hashlib.sha256(block_of_string.encode()).hexdigest() def __repr__(self): return “{} – {} – {} – {} – {}”.format(self.index, self.proof_no, self.prev_hash, self.data, self.timestamp) class BlockChain: def __init__(self): self.chain = [] self.current_data = [] self.nodes = set() self.construct_genesis() def construct_genesis(self): self.construct_block(proof_no=0, prev_hash=0) def construct_block(self, proof_no, prev_hash): block = Block( index=len(self.chain), proof_no=proof_no, prev_hash=prev_hash, data=self.current_data) self.current_data = [] self.chain.append(block) return block u/staticmethod def check_validity(block, prev_block): if prev_block.index + 1 != block.index: return False elif prev_block.calculate_hash != block.prev_hash: return False elif not BlockChain.verifying_proof(block.proof_no, prev_block.proof_no): return False elif block.timestamp <= prev_block.timestamp: return False return True def new_data(self, sender, recipient, quantity): self.current_data.append({ ‘sender’: sender, ‘recipient’: recipient, ‘quantity’: quantity }) return True u/staticmethod def proof_of_work(last_proof): ”’this simple algorithm identifies a number f’ such that hash(ff’) contain 4 leading zeroes f is the previous f’ f’ is the new proof ”’ proof_no = 0 while BlockChain.verifying_proof(proof_no, last_proof) is False: proof_no += 1 return proof_no u/staticmethod def verifying_proof(last_proof, proof): #verifying the proof: does hash(last_proof, proof) contain 4 leading zeroes? guess = f'{last_proof}{proof}’.encode() guess_hash = hashlib.sha256(guess).hexdigest() return guess_hash[:4] == “0000” u/property def latest_block(self): return self.chain[-1] def block_mining(self, details_miner): self.new_data( sender=”0″, #it implies that this node has created a new block receiver=details_miner, quantity= 1, #creating a new block (or identifying the proof number) is awarded with 1 ) last_block = self.latest_block last_proof_no = last_block.proof_no proof_no = self.proof_of_work(last_proof_no) last_hash = last_block.calculate_hash block = self.construct_block(proof_no, last_hash) return vars(block) def create_node(self, address): self.nodes.add(address) return True u/staticmethod def obtain_block_object(block_data): #obtains block object from the block data return Block( block_data[‘index’], block_data[‘proof_no’], block_data[‘prev_hash’], block_data[‘data’], timestamp=block_data[‘timestamp’])
Now, let’s test our code to see if it works.
blockchain = BlockChain() print(“***Mining fccCoin about to start***”) print(blockchain.chain) last_block = blockchain.latest_block last_proof_no = last_block.proof_no proof_no = blockchain.proof_of_work(last_proof_no) blockchain.new_data( sender=”0″, #it implies that this node has created a new block recipient=”Quincy Larson”, #let’s send Quincy some coins! quantity= 1, #creating a new block (or identifying the proof number) is awarded with 1 ) last_hash = last_block.calculate_hash block = blockchain.construct_block(proof_no, last_hash) print(“***Mining fccCoin has been successful***”) print(blockchain.chain)
It worked!
Here is the output of the mining process:
***Mining fccCoin about to start*** [0 – 0 – 0 – [] – 1566930640.2707076] ***Mining fccCoin has been successful*** [0 – 0 – 0 – [] – 1566930640.2707076, 1 – 88914 – a8d45cb77cddeac750a9439d629f394da442672e56edfe05827b5e41f4ba0138 – [{‘sender’: ‘0’, ‘recipient’: ‘Quincy Larson’, ‘quantity’: 1}] – 1566930640.5363243]
Conclusion
There you have it!
That’s how you could create your own blockchain using Python.
Let me say that this tutorial just demonstrates the basic concepts for getting your feet wet in the innovative blockchain technology.
If this coin were deployed as-is, it could not meet the present market demands for a stable, secure, and easy-to-use cryptocurrency.
Therefore, it can still be improved by adding additional features to enhance its capabilities for mining and sending financial transactions.
Nonetheless, it’s a good starting point if you decide to make your name known in the amazing world of cryptos.
If you have any comments or questions, please post them below.
Happy (crypto) coding!
Source: Cryptoors
submitted by djkloud to CryptoTechnology [link] [comments]

[2nd Gen Peer-to-Peer Systems] Had to implement Pastry and Chord For an Assignment // Distributed Hash Tables

Hi folks,
I had to implement Pastry and Chord, they are second generation peer-to-peer systems. The first gen, for e.g would be Gnutella and Napster (Yes, the software that made Sean Parker famous. His role in the movie: The Social Network was played by Justin Timberlake), and the third gen would be BitTorrent.
They are basically distributed hash tables and can be applied for various usage.
Wiki Links:
Pastry) Chord)
Here is my Github Repo: LINK
I tried to write a good README, let me know if I got anything wrong (or missing) or if you have any issues.
Also, I will be doing two more:
- GHS algorithm (for calculating distributed MST)
- BitCoin
Stay tuned if interested.
submitted by callMeSpacetime to learnprogramming [link] [comments]

Introducing Burni: P