SHA-256 Algorithm – Encryption – BitcoinWiki

Bitcoin’s Security and Hash Rate Explained

Bitcoin’s Security and Hash Rate Explained
As the Bitcoin hash rate reaches new all-time highs, there’s never been a better time to discuss blockchain security and its relation to the hashing power and the Proof of Work (PoW) that feed the network. The Bitcoin system is based on a form of decentralized trust, heavily relying on cryptography. This makes its blockchain highly secure and able to be used for financial transactions and other operations requiring a trustless ledger.
Far from popular belief, cryptography dates back to thousands of years ago. The same root of the word encryption — crypt — comes from the Greek word ‘kryptos’, meaning hidden or secret. Indeed, humans have always wanted to keep some information private. The Assyrians, the Chinese, the Romans, and the Greeks, they all tried over the centuries to conceal some information like trade deals or manufacturing secrets by using symbols or ciphers carved in stone or leather. In 1900 BC, Egyptians used hieroglyphics and experts often refer to them as the first example of cryptography.
Back to our days, Bitcoin uses cryptographic technologies such as:
  1. Cryptographic hash functions (i.e. SHA-256 and RIPEMD-160)
  2. Public Key Cryptography (i.e. ECDSA — the Elliptic Curve Digital Signature Algorithm)
While Public Key Cryptography, bitcoin addresses, and digital signatures are used to provide ownership of bitcoins, the SHA-256 hash function is used to verify data and block integrity and to establish the chronological order of the blockchain. A cryptographic hash function is a mathematical function that verifies the integrity of data by transforming it into a unique unidentifiable code.
Here is a graphic example to make things more clear:

– Extract from the MOOC (Massive Open Online Course) in Digital Currencies at the University of Nicosia.
Furthermore, hash functions are used as part of the PoW algorithm, which is a prominent part of the Bitcoin mining algorithm and this is what is of more interest to understand the security of the network. Mining creates new bitcoins in each block, almost like a central bank printing new money and creates trust by ensuring that transactions are confirmed only when enough computational power is devoted to the block that contains them. More blocks mean more computation, which means more trust.
With PoW, miners compete against each other to complete transactions on the network and get rewarded. Basically they need to solve a complicated mathematical puzzle and a possibility to easily prove the solution. The more hashing power, the higher the chance to resolve the puzzle and therefore perform the proof of work. In more simple words, bitcoins exist thanks to a peer to peer network that helps validate transactions in the ledger and provides enough trust to avoid that a third party is involved in the process. It also exists because miners give it life by resolving that computational puzzle, through the mining reward incentive they are receiving.
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submitted by BlockDotCo to u/BlockDotCo [link] [comments]

4A Coin Whitepaper

4A Coin: A web-based cryptocurrency network. Summary~ Because the first generation cryptocurrencies such as Bitcoin, Ethereum and Litecoin distribute the money issuing task according to the power of machines such as GPU and CPU, they accumulate the payments in the mempool and they mine by changing the nonce number randomly or by continuously increasing it and trying repeatedly until they find a hash summary that matches the difficulty they specify, instead of processing the payments made in real-time instantly. This solution is ingenious if you want to use digital currency as a value storage tool. But when you try to use these digital currencies to pay for coffee or purchase a product online, it stands out as a disadvantage since you have to pay commissions to those miners and have to wait too long. As you know, the power of large payment solutions, such as Paypal or Western Union, comes from their servers and software. We also started working on a noncentralized, blockchain-protected end-toend (P2P) cryptocurrency that works as a web service. In such a case, for the system to survive and ensure security, instead of paying for the server cost, we set up a system where servers, that are nodes in the system, can get paid, provided they just stay online for 44 hours instead of mining. People get paid for a useful service they provide instead of wasting their time. There will be a reason for people to install this system on their servers because they are rewarded as long as they remain as servers. When people send an end-to-end payment, the servers, by finding a summary of this payment (They find this summary in order for all systems to meet at a common point and validate payments, and because it is a necessity of the blockchain architecture), ending with 4A, including the time, the sender, the receiver, amount, summary of the previous transaction and the data contained in a digital signature indicating that the sender is actually sending it, without any difficulty and they add it to their databases. Because there are no such concepts as block size or mining involved in any way, the registration process is completed instantly. We use a task queue management library called Celery Project, which is used by companies such as Instagram and Mozilla to prevent complication that may occur if 100 transactions take place within the same second. Security~ If you noticed when you entered the site, I told you that it was safer than Visa. This may seem an ambitious sentence for many, but if you actually know what you're doing when you buy a product online, you are aware of the risks involved. Risk & Problem~ When you type information in the payment form, such as credit card, CVV, and so on, malicious people on the web can read the data you send through these forms. Just because of this, payment solutions require you to add an SSL certificates to your site. These SSL certificates actually save your data using cryptography and protect it until it reaches the recipient. Well, what if the seller has bad intentions? Solution~ 4A Coin encrypts your payments using the Elliptic Curve Digital Signature Algorithm (ECDSA) and sends a signature confirming that you want to pay instead of giving your digital password to the network. This is actually the idea of Satoshi Nakamoto and it is known as P2PKH in Bitcoin. So if we actually compare 4A Coin to a credit card, then no one will ever see your credit card details. In addition, SSL certificate is no longer needed because a malicious user who can tap into your network seeing your payment signature won't change anything, besides it is already publicly shared everywhere. Thus, we have already gotten rid of certificate issues like security and SSL in the first place. Commission Solution~ When you benefit from a local payment solution, you will have to pay a commission to the companies you work with, between 5% and 20% of your sales. The coins you use in 4A Coin are already generated by the nodes, so they do not ask for a commission. Thanks to this, you do not pay commissions for transactions nor for any other reason. Wallets ~ wallet_id ~ 4A01eaedb37fc09fdb94c6d632adf9f63d private_key ~ cbc949239a333559f5dd8b0b5cf3d32923c2cab3 7c2bde9c8042a3dafe59a6b9 Your wallet is actually an ECDSA key pair. At first, we used RSA for this, but we had to switch to ECDAS because the keys were too long in the RSA and were taking too much space. Users have public keys, private keys, and wallet addresses created by processing public keys. Public key is not visible to users on the system. Instead, they will see a short version of a summary generated by public key processing as their wallet. def generate_wallet_from_pkey(public_key): binmnmn = public_key.encode('utf-8') first_step = 34 - len(settings.CURRENCY) wallet_id = hashlib.sha256(binmnmn).hexdigest() wallet_id = wallet_id[-first_step:] wallet_id = "".join((settings.CURRENCY, wallet_id)) return wallet_id This function simply creates a wallet from the simply given public key's SHA-256 summary. Public keys are required for the approval of digital signatures, so it is necessary to keep the public key in transactions. Payments~ When a user makes a payment, the payment time (in epoch format & GMT), the sender's address, the recipient's address, the summary of the previous transaction and the amount sent are transferred to a dictionary. This dictionary can be sorted differently on different computers, and to prevent this, the contents of this dictionary must be organized in a way that is ordered from A to Z, and will give the same result in everyone. data = collections.OrderedDict(sorted(data.items())) With the above code, we can create a stable dictionary that can work globally. Finally, we take a summary of this dictionary and record it in our database, and broadcast it to other servers that we have recorded it. Peer to Peer~ We use the TCP port and web socket technology to ensure that the system is P2P. For the script to work, you need to use Python3. Because, we use the Twister Matrix Library and the Autobahn Python libraries to provide real time transactions. The port we use globally is the 9000th port. There are 3 different types of broadcasting in real time processes: The first one is “Hi, I'm a new node, please add me to your network” and the other one is “Hi, I'm a new process, please verify me”. This is parsed on the server side and necessary actions are taken. The third broadcasting type will be explained in the proof of cloud section. Mining ~ A total of 450 million of 4A Coins will be issued with 300.000.000 Pre-mined. 150 million coins will be mined by a method called Proof of Cloud. Proof of Cloud~ Proof of Cloud or POC refers to a method of earning based on time as a server instead of mining. Each node, by staying online for 44 hours, will send a message as "I have been online for 44 hours, so check my database to see if I have been online by reviewing my recent transactions." If it proves that you have approved transactions for the last 44 hours, you will be eligible to receive the reward. Celery & Redis~ We use Celery, a library that automatically controls tasks so that certain processes can be repeated at certain times in the system. Celery needs Redis to work. Redis is an open source NoSQL (NoSQL is the name given to database systems that store “non-relational” data schematically. NoSQL is literally being used in the sense of "not-only- SQL", which means "only SQL is not used".) software written on Linux as the pure version. Keeping the system up and running~ We use Gunicorn 'Green Unicorn' and Nginx, the Python WSI HTTP Server, to ensure that the system can handle high load and maintain its endurance; Nginx is a Web server designed to focus on high concurrency, high performance and low memory usage. It can also be used as a reverse proxy server, load balancer, and HTTP cache. We were actually using Supervisord to keep all these systems up and running, but since Supervisord did not work with Python3 we started using Circusd developed by the Mozilla Foundation and we were more satisfied with it than Supervisiord. It is much easier to install and use, requires Tornado framework to work on its own, and works correctly with the 4.5.3 version of Tornado. This version is already installed automatically in requirements.txt, but it is important that you know this detail.
submitted by 4acoin to u/4acoin [link] [comments]

4A Coin Whitepaper

4A Coin: A web-based cryptocurrency network. Summary~ Because the first generation cryptocurrencies such as Bitcoin, Ethereum and Litecoin distribute the money issuing task according to the power of machines such as GPU and CPU, they accumulate the payments in the mempool and they mine by changing the nonce number randomly or by continuously increasing it and trying repeatedly until they find a hash summary that matches the difficulty they specify, instead of processing the payments made in real-time instantly. This solution is ingenious if you want to use digital currency as a value storage tool. But when you try to use these digital currencies to pay for coffee or purchase a product online, it stands out as a disadvantage since you have to pay commissions to those miners and have to wait too long. As you know, the power of large payment solutions, such as Paypal or Western Union, comes from their servers and software. We also started working on a noncentralized, blockchain-protected end-toend (P2P) cryptocurrency that works as a web service. In such a case, for the system to survive and ensure security, instead of paying for the server cost, we set up a system where servers, that are nodes in the system, can get paid, provided they just stay online for 44 hours instead of mining. People get paid for a useful service they provide instead of wasting their time. There will be a reason for people to install this system on their servers because they are rewarded as long as they remain as servers. When people send an end-to-end payment, the servers, by finding a summary of this payment (They find this summary in order for all systems to meet at a common point and validate payments, and because it is a necessity of the blockchain architecture), ending with 4A, including the time, the sender, the receiver, amount, summary of the previous transaction and the data contained in a digital signature indicating that the sender is actually sending it, without any difficulty and they add it to their databases. Because there are no such concepts as block size or mining involved in any way, the registration process is completed instantly. We use a task queue management library called Celery Project, which is used by companies such as Instagram and Mozilla to prevent complication that may occur if 100 transactions take place within the same second. Security~ If you noticed when you entered the site, I told you that it was safer than Visa. This may seem an ambitious sentence for many, but if you actually know what you're doing when you buy a product online, you are aware of the risks involved. Risk & Problem~ When you type information in the payment form, such as credit card, CVV, and so on, malicious people on the web can read the data you send through these forms. Just because of this, payment solutions require you to add an SSL certificates to your site. These SSL certificates actually save your data using cryptography and protect it until it reaches the recipient. Well, what if the seller has bad intentions? Solution~ 4A Coin encrypts your payments using the Elliptic Curve Digital Signature Algorithm (ECDSA) and sends a signature confirming that you want to pay instead of giving your digital password to the network. This is actually the idea of Satoshi Nakamoto and it is known as P2PKH in Bitcoin. So if we actually compare 4A Coin to a credit card, then no one will ever see your credit card details. In addition, SSL certificate is no longer needed because a malicious user who can tap into your network seeing your payment signature won't change anything, besides it is already publicly shared everywhere. Thus, we have already gotten rid of certificate issues like security and SSL in the first place. Commission Solution~ When you benefit from a local payment solution, you will have to pay a commission to the companies you work with, between 5% and 20% of your sales. The coins you use in 4A Coin are already generated by the nodes, so they do not ask for a commission. Thanks to this, you do not pay commissions for transactions nor for any other reason. Wallets ~ wallet_id ~ 4A01eaedb37fc09fdb94c6d632adf9f63d private_key ~ cbc949239a333559f5dd8b0b5cf3d32923c2cab3 7c2bde9c8042a3dafe59a6b9 Your wallet is actually an ECDSA key pair. At first, we used RSA for this, but we had to switch to ECDAS because the keys were too long in the RSA and were taking too much space. Users have public keys, private keys, and wallet addresses created by processing public keys. Public key is not visible to users on the system. Instead, they will see a short version of a summary generated by public key processing as their wallet. def generate_wallet_from_pkey(public_key): binmnmn = public_key.encode('utf-8') first_step = 34 - len(settings.CURRENCY) wallet_id = hashlib.sha256(binmnmn).hexdigest() wallet_id = wallet_id[-first_step:] wallet_id = "".join((settings.CURRENCY, wallet_id)) return wallet_id This function simply creates a wallet from the simply given public key's SHA-256 summary. Public keys are required for the approval of digital signatures, so it is necessary to keep the public key in transactions. Payments~ When a user makes a payment, the payment time (in epoch format & GMT), the sender's address, the recipient's address, the summary of the previous transaction and the amount sent are transferred to a dictionary. This dictionary can be sorted differently on different computers, and to prevent this, the contents of this dictionary must be organized in a way that is ordered from A to Z, and will give the same result in everyone. data = collections.OrderedDict(sorted(data.items())) With the above code, we can create a stable dictionary that can work globally. Finally, we take a summary of this dictionary and record it in our database, and broadcast it to other servers that we have recorded it. Peer to Peer~ We use the TCP port and web socket technology to ensure that the system is P2P. For the script to work, you need to use Python3. Because, we use the Twister Matrix Library and the Autobahn Python libraries to provide real time transactions. The port we use globally is the 9000th port. There are 3 different types of broadcasting in real time processes: The first one is “Hi, I'm a new node, please add me to your network” and the other one is “Hi, I'm a new process, please verify me”. This is parsed on the server side and necessary actions are taken. The third broadcasting type will be explained in the proof of cloud section. Mining ~ A total of 450 million of 4A Coins will be issued with 300.000.000 Pre-mined. 150 million coins will be mined by a method called Proof of Cloud. Proof of Cloud~ Proof of Cloud or POC refers to a method of earning based on time as a server instead of mining. Each node, by staying online for 44 hours, will send a message as "I have been online for 44 hours, so check my database to see if I have been online by reviewing my recent transactions." If it proves that you have approved transactions for the last 44 hours, you will be eligible to receive the reward. Celery & Redis~ We use Celery, a library that automatically controls tasks so that certain processes can be repeated at certain times in the system. Celery needs Redis to work. Redis is an open source NoSQL (NoSQL is the name given to database systems that store “non-relational” data schematically. NoSQL is literally being used in the sense of "not-only- SQL", which means "only SQL is not used".) software written on Linux as the pure version. Keeping the system up and running~ We use Gunicorn 'Green Unicorn' and Nginx, the Python WSI HTTP Server, to ensure that the system can handle high load and maintain its endurance; Nginx is a Web server designed to focus on high concurrency, high performance and low memory usage. It can also be used as a reverse proxy server, load balancer, and HTTP cache. We were actually using Supervisord to keep all these systems up and running, but since Supervisord did not work with Python3 we started using Circusd developed by the Mozilla Foundation and we were more satisfied with it than Supervisiord. It is much easier to install and use, requires Tornado framework to work on its own, and works correctly with the 4.5.3 version of Tornado. This version is already installed automatically in requirements.txt, but it is important that you know this detail.
submitted by 4acoin to u/4acoin [link] [comments]

FOR IMMEDIATE RELEASE: After Butterfly Labs collapses, engineers find new jobs at 21 Inc.

BEGIN BLOG POST

After Butterfly Labs collapses, engineers find new jobs at 21 Inc.

A bitcoin miner has shipped on time. Yes, that is news. A new venture-capital backed company, 21 Inc., has released a miniature bitcoin miner that they call a "Bitcoin computer". For $399.99, you get a Raspberry Pi, an SHA-256 ASIC board, and a giant fan.
Again, this is news: normally, a manufacturer of bitcoin miners would overdesign and underengineer their equipment, or, if they managed to ship something functional, it would be so poorly engineered -- and over budget -- that it be an explosion waiting to happen and/or priced comparably to a four-door sedan.
21 Inc. has done something remarkable in the Bitcoin world: they started a company that operates like a legitimate business. They're even listed on Amazon.com, a company that's so strict with vendors that Nintendo was kicked off their system for not kissing enough customer ass.
Okay, enough with the praise.

This thing sucks.

The 21.co "computer" certainly deserves a place in the VC world, along with the other products consisting of wild promises and inane use cases. For the price of 4 Raspberry Pi computer kits, you get the following:
(If you have a remote desire to develop applications that use bitcoin, stop here. Go through that list and buy just those items above. You don't need anything else. If you're looking for comedy, or if you're a sucker with too much money, read on...)

Is that all I get for my money?

Those products alone don't allow you to make Bitcoin applications, apparently. You need these things, too:

How about the software demos?

It's difficult to justify developing a $400 computer that can't do much. So, to entice some customers, 21 Inc. included demos that try really hard to make customers feel inspired. Here are just a few things that 21 Inc. claims were totally impossible before their product existed:

What are the real customers saying?

The packaging is slick:
"This @21dotco computer came already opened..."
The hardware is reliable:
"...it must have lost power, which caused my SSH keys to become corrupted."
The software is revolutionary:
"...it will be more expensive to pay for your spotify subscription via your electricity bill, but a lot of people don't care."

I want to buy it anyway!

Go ahead. I won't stop you. Oh, and 21 Inc. doesn't accept bitcoins.
END BLOG POST
submitted by theirmoss to Buttcoin [link] [comments]

My Collection of information for when someone states where does Bitcoin, or Crypto-currencies derive their value

Let’s start with some basics first then we can move forward. Your question is where does Bitcoin derive its value from? Well that is a multifaceted answer. Its Utility creates the demand, plus it has a relatively high scarcity, but that is an over-simplified answer. A few other factors need to be addressed. The first point is the security of the block-chain, and the second is the openness of the block-chain which is derived from the public ledger. It literally records every transaction for public records which are available to any, and everyone to review. This allows it to stand up to public scrutiny, and a thorough technical analysis.
We will start here for you. This is the basis of the whole concept.
A Block-chain is a continuously growing list of records, called blocks, which are linked and secured using cryptography. Each block typically contains a hash pointer as a link to a previous block, a timestamp and transaction data. By design, block-chains are inherently resistant to modification of the data. A block-chain is defined as an open, distributed ledger that can record transactions between two, or more parties efficiently and in a verifiable, and permanent way. For use as a distributed ledger, a block-chain is typically managed by a peer-to-peer network collectively adhering to a protocol for validating new blocks. Once recorded, the data in any given block cannot be altered retroactively without the alteration of all subsequent blocks, which requires collusion of the network majority.
Block-chains are secure by design and are an example of a distributed computing system with high Byzantine fault tolerance. Decentralized consensus has therefore been achieved with a block-chain. This makes block-chains potentially suitable for the recording of events, medical records, and other records management activities, such as identity management, transaction processing, documenting provenance, or food traceability. The invention of the block-chain for bitcoin made it the first digital currency to solve the double spending problem without the need of a trusted authority or central server. The bitcoin design has been the inspiration for other applications. Block-chain also has incorporated the Merkle Tree, and Fast Merkle Trees. A Hash tree or Merkle tree is a tree in which every leaf node is labelled with a data block and every non-leaf node is labelled with the cryptographic hash of the labels of its child nodes. Hash trees allow efficient and secure verification of the contents of large data structures. Hash trees are a generalization of hash lists and hash chains. Demonstrating that a leaf node is a part of a given binary hash tree requires computing a number of hashes proportional to the logarithm of the number of leaf nodes of the tree; this contrasts with hash lists, where the number is proportional to the number of leaf nodes itself. Hash trees can be used to verify any kind of data stored, handled and transferred in and between computers. Currently the main use of hash trees is to make sure that data blocks received from other peers in a peer-to-peer network are received undamaged and unaltered, and even to check that the other peers do not lie and send fake blocks. Suggestions have been made to use hash trees in trusted computing systems. Hash trees are also used in hash-based cryptography.
Hash trees are used in the IPFS, Btrfs and ZFS file systems (to counter data degradation), BitTorrent protocol, Dat protocol, Apache Wave protocol, the Bitcoin and Ethereum peer-to-peer networks, the Certificate Transparency framework, and a number of NoSQL.
Whether you understand it, or not we will be moving more to this as a standard for all most all industries. Yes, the United States is looking at getting rid of Social Security numbers in favor of your identity being stored on the block-chain, in fact it is already in the works as they are in the research of feasibility stage.
What you need to is familiarize yourself with the following regarding block-chain protocols.
Proof of Work (POW) A Proof of Work is a piece of data which is difficult (costly, time-consuming) to produce but easy for others to verify and which satisfies certain requirements. Producing a proof of work can be a random process with low probability so that a lot of trial and error is required on average before a valid proof of work is generated. Bitcoin uses the Hash-cash proof of work system.
One application of this idea is using Hash-cash as a method to prevent email spam, requiring a proof of work on the email's contents (including the to address), on every email. Legitimate emails will be able to do the work to generate the proof easily (not much work is required for a single email), but mass spam emailers will have difficulty generating the required proofs (which would require huge computational resources).
Hash-cash proofs of work are used in Bitcoin for block generation. In order for a block to be accepted by network participants, miners must complete a proof of work which covers all of the data in the block. The difficulty of this work is adjusted so as to limit the rate at which new blocks can be generated by the network to one every 10 minutes. Due to the very low probability of successful generation, this makes it unpredictable which worker computer in the network will be able to generate the next block.
For a block to be valid it must hash to a value less than the current target; this means that each block indicates that work has been done generating it. Each block contains the hash of the preceding block, thus each block has a chain of blocks that together contain a large amount of work. Changing a block (which can only be done by making a new block containing the same predecessor) requires regenerating all successors and redoing the work they contain. This protects the block chain from tampering.
The most widely used proof-of-work scheme is based on SHA-256 and was introduced as a part of Bitcoin. Some other hashing algorithms that are used for proof-of-work include Scrypt, Blake-256, CryptoNight, HEFTY1, Quark, SHA-3, scrypt-jane.
Proof of Stake (POS) Proof-of-stake (POS) is a type of algorithm by which a cryptocurrency block-chain network aims to achieve distributed consensus. In POS-based cryptocurrencies the creator of the next block is chosen via various combinations of random selection and wealth or age (i.e. the stake).In general, a proof of stake algorithm looks as follows. The block-chain keeps track of a set of validators, and anyone who holds the block-chain's base cryptocurrency (in Ethereum's case, ether) can become a validator by sending a special type of transaction that locks up their ether into a deposit. The process of creating and agreeing to new blocks is then done through a consensus algorithm that all current validators can participate in.
There are many kinds of consensus algorithms, and many ways to assign rewards to validators who participate in the consensus algorithm, so there are many "flavors" of proof of stake. From an algorithmic perspective, there are two major types: chain-based proof of stake and BFT-style proof of stake.
In chain-based proof of stake, the algorithm pseudo-randomly selects a validator during each time slot (every period of 10 seconds might be a time slot), and assigns that validator the right to create a single block, and this block must point to some previous block (normally the block at the end of the previously longest chain), and so over time most blocks converge into a single constantly growing chain.
In BFT-style proof of stake, validators are randomly assigned the right to propose blocks, but agreeing on which block is canonical is done through a multi-round process where every validator sends a "vote" for some specific block during each round, and at the end of the process all (honest and online) validators permanently agree on whether or not any given block is part of the chain. Note that blocks may still be chained together; the key difference is that consensus on a block can come within one block, and does not depend on the length or size of the chain after it. This is what Ethereum is moving to later in 2018.
Advantages of POS over POW No need to consume large quantities of electricity in order to secure a block-chain ( it's estimated that both Bitcoin and Ethereum burn over $1 million worth of electricity and hardware costs per day as part of their consensus mechanism). Because of the lack of high electricity consumption, there is not as much need to issue as many new coins in order to motivate participants to keep participating in the network. It may theoretically even be possible to have negative net issuance, where a portion of transaction fees are "burned" and so the supply goes down over time. Proof of stake opens the door to a wider array of techniques that use game-theoretic mechanism design in order to better discourage centralized cartels from forming and, if they do form, from acting in ways that are harmful to the network. Reduced centralization risks, as economies of scale are much less of an issue. $10 million of coins will get you exactly 10 times higher returns than $1 million of coins, without any additional disproportionate gains because at the higher level you can afford better mass-production equipment. Ability to use economic penalties to make various forms of 51% attacks vastly more expensive to carry out than proof of work.
Delegated Proof of Stake (DPOS) Delegated Proof-of-Stake, on the other hand, works slightly differently. It is a more efficient PoS algorithm altogether, and seemingly provides more decentralization when it comes to issuing stake rewards to more people. Moreover, DPOS provides reliably confirmed transactions on the networks that implement this technology. If it were to be added to bitcoin at some point, it could potentially speed up transaction times, even though it would add inflation to the ecosystem as well.
Under the hood, DPOS uses a reputation system and real-time voting to achieve consensus. To be more specific, a panel of trusted parties has to be established, with all of its members eligible to create blocks and prevent non-trusted parties from participating. Delegates, the parties responsible for creating blocks, are unable to change transaction details. However, they can prevent specific transactions from being included in the next network block. This seemingly requires a fair bit of trust, which makes the concept look far less appealing.
However, there is a caveat. Any transaction not included in the next block, or a block failing to create, will mean the next network block is twice the size. In a way, this prevents malicious intent to block certain transactions or blocks being created in the allotted time period. All it does is perhaps slightly delay said transaction or block, but it is seemingly impossible to prevent inclusion and creation in the long run.
Moreover, anyone who behaves in a nefarious way will have their behavior exposed to the public. Community members of the DPOS-capable currencies can vote to have said person removed as a delegate altogether. It appears as if cheating under DPOS rules is not only impossible, but it is not in anybody’s best interest to do so either. It is equally possible to have more or fewer delegates as part of the network, although that may not necessarily be beneficial either. It is always possible to change the number of delegates, though, which is an important factor to keep in mind.
It is also worth mentioning delegates in a DPOS ecosystem are paid for the creation of blocks and inclusion of transactions. However, the delegates can use these funds to pay for marketing or lobbying efforts, which benefit the exposure of the cryptocurrency network as a whole. Network stakeholders determine how much delegates are paid for their efforts.
Delegated Byzantine Fault Tolerance (dBFT) The dBFT (Delegated Byzantine Fault Tolerance) algorithm
Consensus is about trying to maintain one version of truth. Over time we have transactions that we want to record in this ledger (book of truth). Because block-chains run decentralized around the world, and they receive different transactions at different times, they can often disagree about what is truth.
The key is to get consensus one way or another, otherwise all sorts of bad things can happen (double spending).
dBFT Delegated Byzantine Fault Tolerance is a fancy and cool name for a solution to getting eventual consensus under certain conditions.
The condition is really simple: as long as less than 1/3 of bookkeeper nodes are BAD actors, you can get eventual consensus and everyone is happy.
That's the main thing to remember, and I'll explain why 1/3 and not 1/4 or any other fraction.
An Analogy - Painting the walls A King has decided to paint the walls of his castle. He's decided it is either going to be Green (G) or Black (B). He doesn't mind which of the two but he wants consistency throughout the kingdom. And he wants all of his sons and daughters to agree on the color.
So he calls his four painters to come over and sends a signed message to his sons and daughters: I am getting my painters to redecorate my walls. I am torn between Green and Black. To resolve this, I want you, my beloved sons and daughters, to agree on the color and tell my painters and they will paint my walls. As soon as a painter hears from you and you can prove that 2/3 of my family agree on a color, she will start painting that color. Good luck.
The painters are all contactable by any of the sons and daughters. However, due to fighting between the family, the sons and daughters don't all talk to each other directly. Instead they pass messages between them. They all connected, just not directly.
Some of the family is evil and they want to get at least one of the painters to paint the wrong color. The family discuss and decide on the following protocol: 1. The oldest member of the family is elected speaker. He or she will communicate the chosen color with their signature.
Everyone will communicate that color to everyone else (until everyone is informed.) along with their signatures. If you hear from 2/3 of people the same color, then you can call any or all of the painters and tell them. If not, wait for some time and then elect the next oldest member as the speaker and repeat.
These signatures are magic and cannot be forged, and also are without a doubt proof that the person did sign it. Proving consensus protection.
With this setup, we can now prove that as long as less than a 1/3 of the family are evil, it is impossible for any of the painters to get a different message to the others and thereby paint the walls inconsistently.
The proof goes like this. Imagine that the evil members of the family belong to a secret clan F and have managed to insert themselves in between the other family members such that the rest of the family is split into two groups, R1 and R2. R1 members can talk to each other and to F but they can't talk directly to R2. And the same for R2. So F is in control here as they can control what information flows from R1 to R2 and vice versa.
In order for them to exact chaos, they need to get 2/3 of the signatures (including theirs) to be Green and Black. Remember, they can sign Green and pass that message to one person and also sign Black and pass that message to another person.
The next bit is really easy. In order to get 2/3 of the signatures, we need the size of F and R1 (the number of people in those two groups) to be >= 2/3 of the total. We also need that to be true for F and R2. That way R1 members think that it's green (for example) and the other group think it's black and they tell the painters and it all goes wrong.
However, because F is less than a 1/3 (remember, 2/3 people are honest), then it's impossible for BOTH F+R1 and F+R2 to be >= 2/3 x N. By using the fact that F+R1+R2 = N (the total number in the family) and a bit of algebraic rearrangement, you can prove that to get two separate consensus you requires F >= 1/3. Ta da - that's impossible as F < 1/3.
dBFT doesn't guarantee consensus in the sense that it's possible the messaging network is broken and people just can't talk to each other. But it gives protection guarantees that if you do reach consensus you can't then reach some other different consensus later. As long as the bad actors are less than a 1/3 of the bookkeepers (the Family), then everything is all good. This is the important part of ensuring the integrity of the system going forward.
Now that we have stated that You will need to read about the following.
Consensus Nodes (Bookkeeper Nodes) *See dBFT section
Master Nodes *See Full Node, but used in a POS block-chain. These also pay out fees to you for running a Master Node.
Full Nodes These are usually POW block-chains
Full nodes download every block and transaction and check them against Bitcoin's core consensus rules. Here are examples of consensus rules, though there are many more:
· Blocks may only create a certain number of bitcoins. (Currently 12.5 BTC per block.)
· Transactions must have correct signatures for the bitcoins being spent.
· Transactions/blocks must be in the correct data format.
· Within a single block-chain, a transaction output cannot be double-spent.
If a transaction or block violates the consensus rules, then it is absolutely rejected, even if every other node on the network thinks that it is valid. This is one of the most important characteristics of full nodes: they do what's right no matter what. For full nodes, miners actually have fairly limited power: they can only reorder or remove transactions, and only by expending a lot of computing power. A powerful miner is able to execute some serious attacks, but because full nodes rely on miners only for a few things, miners could not completely change or destroy Bitcoin.
Nodes that have different consensus rules are actually using two different networks/currencies. Changing any of the consensus rules requires a hard fork, which can be thought of as creating a new currency and having everyone move to it. Consensus rules are different from policy rules, which specify how a node or miner prioritizes or discourages certain things. Policy rules can be changed freely, and different nodes can have different policy rules. Because all full nodes must use exactly the same consensus rules in order to remain compatible with each other, even duplicating bugs and oddities in the original consensus rules, creating a full node from scratch is extremely difficult and dangerous. It is therefore recommended that everyone who wishes to run a full node use software based on the reference client, which is the only client guaranteed to behave correctly.
At minimum, a full node must download every transaction that has ever taken place, all new transactions, and all block headers. Additionally, full nodes must store information about every unspent transaction output until it is spent. By default full nodes are inefficient in that they download each new transaction at least twice, and they store the entire block chain (>60 GB) forever, even though only the unspent transaction outputs (<2 GB) are required.
Again to give you a slightly different over-simplified answer Bitcoin’s value is derived from the energy it cost to run the block-chain whether its coal-powered, hydro-powered, natural gas powered, or nuclear reactor-powered electricity.
Will Bitcoin be replaced by another block-chain as the reserve standard? Well it’s a possibility, but not likely any time soon. Most new Alt-coins are here to Compliment Bitcoin. Why do I say this? Well the goal is a Decentralized Smart Economy with the least amount of Centralized control possible. The Lightning Network integrates Bitcoin, Litecoin, and Vertcoin.
Bitcoin has 21,000,000 coins when they are finally fully released. This requires ASIC Miners a rather expensive, and specialized Computer. The block times are ten minutes. These for the older versions will still run about $20,000. It may have changed a little since I last looked, but the cutting edge ones will be much more.
Litecoin has 84,000,000 coins when they are finally fully released. This requires ASIC Miners a rather expensive, and specialized Computer. The block times are 2.5 minutes. It’s an improved clone of Bitcoin.
Vertcoin has 84,000,000 coins when they are finally fully released. The average Joe can mine this with a good graphics card. The block times are 2.5 minutes. It’s an modified clone of Litecoin.
Ethereum Is a Smart contract platform. It has many uses cases. Too many to list. This will be moved to a POS block-chain.
NEO Is a Smart contract platform. It has many uses cases. Too many to list. This has a lot of things in common with Ethereum, but at the same time it doesn’t. This uses the dBFT system, and has more common programming languages for Smart Contracts.
ARK this is a Smart Bridge ecosystem. It’s aim is to build bridges to other block-chains. Its aim is to be the hub of this new block-chain economy. Ark has bridged to Bitcoin, and also to Ethereum. They have plans for NEO, and Monero as well in the future. ARK has many other use cases I haven’t discussed, and don’t have time to right now.
These very originally made to compete with each other, but have found ways to coexist, but are also still be competitive with each other at the same time. I have kept this section short. I could spend many more pages writing about these Cryptocurrencies, and many more. These are the building blocks for the Smart Economy.
This is what Bitcoin, and all of the Alt-coins were brought about to fix.
· People used to pay each other in gold and silver. Difficult to transport. Difficult to divide.
· Paper money was invented. A claim to gold in a bank vault. Easier to transport and divide.
· Banks gave out more paper money than they had gold in the vault. They ran “fractional reserves”. A real money maker. But every now and then, banks collapsed because of runs on the bank.
· Central banking was invented. Central banks would be lenders of last resort. Runs on the bank were thus mitigated by banks guaranteeing each other’s deposits through a central bank. The risk of a bank run was not lowered. Its frequency was diminished and its impact was increased. After all, banks remained basically insolvent in this fractional reserve scheme.
· Banks would still get in trouble. But now, if one bank got in sufficient trouble, they would all be in trouble at the same time. Governments would have to step in to save them.
· All ties between the financial system and gold were severed in 1971 when Nixon decided that the USD would no longer be exchangeable for a fixed amount of gold. This exacerbated the problem, because there was now effectively no limit anymore on the amount of paper money that banks could create.
· From this moment on, all money was created as credit. Money ceased to be supported by an asset. When you take out a loan, money is created and lent to you. Banks expect this freshly minted money to be returned to them with interest. Sure, banks need to keep adequate reserves. But these reserves basically consist of the same credit-based money. And reserves are much lower than the loans they make.
· This led to an explosion in the money supply. The Federal Reserve stopped reporting M3 in 2006. But the ECB currently reports a yearly increase in the supply of the euro of about 5%.
· This leads to a yearly increase in prices. The price increase is somewhat lower than the increase in the money supply. This is because of increased productivity. Society gets better at producing stuff cheaper all the time. So, in absence of money creation you would expect prices to drop every year. That they don’t is the effect of money creation.
· What remains is an inflation rate in the 2% range.
· Banks have discovered that they can siphon off all the productivity increase + 2% every year, without people complaining too much. They accomplish this currently by increasing the money supply by 5% per year, getting this money returned to them at an interest.
· Apart from this insidious tax on society, banks take society hostage every couple of years. In case of a financial crisis, banks need bailouts or the system will collapse.
· Apart from these problems, banks and governments are now striving to do away with cash. This would mean that no two free men would be able to exchange money without intermediation by a bank. If you believe that to transact with others is a fundamental right, this should scare you.
· The absence of sound money was at the root of the problem. We were force-fed paper money because there were no good alternatives. Gold and silver remain difficult to use.
· When it was tried to launch a private currency backed by precious metals (Liberty dollar), this initiative was shut down because it undermined the U.S. currency system. Apparently, a currency alternative could only thrive if “nobody” launched it and if they was no central point of failure.
· What was needed was a peer-to-peer electronic cash system. This was what Satoshi Nakamoto described in 2008. It was a response to all the problems described above. That is why he labeled the genesis block with the text: “03/Jan/2009 Chancellor on brink of second bailout for banks.”. Bitcoin was meant to be an alternative to our current financial system.
To answer you on if this is a bubble. I personally do not see it that way at the moment. There will always be corrections in Crypto, or any field of Investing. Yes we have seen an unprecedented meteoric rise in cryptocurrencies there will be severe corrections in the future, but there will not be a ninety-nine percent crash like you are stating unless there is another Great Depression, or severe economic collapse. Cryptocurrencies are currently the greatest potential wealth equalizer around the world.
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Bitcoin SHA256 Mining Farm HashFlare how to setup pools on SHA-256 mine Bitcoins. You Can Use SHA 256 Hardware to Mine X11 or Scrypt What is SHA256?  Bitcoin mining using Raspberry Pi BITCOIN MINING trailer

Timer Miner is a Cryptocurrency Bitcoin Cloud Mining company. The company provides modern, high-efficiency platform rental services for Bitcoin mining. We guarantee an instant connection, access 24/7, operation without any interruptions, real-time mining monitoring, easy-to-use and secure platform as well daily mining outputs. So the mining algorithm Bitcoin uses is SHA-256. Now in order to successfully mine Bitcoins using this algorithm you often need hash rates well into the gigahashes per second, and generally higher. Algorithm SHA-256 is a member of the SHA-2 cryptographic hash functions designed by the NSA. SHA stands for Secure Hash Algorithm. Cryptographic hash functions are mathematical operations run on digital data; by comparing the computed "hash" (the output from execution of the algorithm) to a known and expected hash value, a person can determine the data's integrity. This is a diagram of what the SHA-256 state looks like, and we don't need to know all of the details of this to understand how Bitcoin works, but I'll give a high-level overview to give an idea of the task that needs to be solved by the miners. The SHA-256 algorithm relies on the Merkle-Damgard construction method, which stipulates that the initial index be divided up into blocks as soon as the change is made, and those, in turn, into 16 words. The Bitcoin network uses the SHA-256 algorithm for proof of work in mining and to make bitcoin addresses more private and secure.

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Bitcoin SHA256 Mining Farm

Mining Bitcoin with Excel - Duration: 7:17. Knowledge 181,876 views. 7:17. Pawn Stars: 20 SUPER RARE HIGH VALUE ITEMS ... What is a Bitcoin hash and SHA-256 - Duration: 1:54. This is a BFL 50 Gh/s mining rig mining sha-256 algorithm crypto coins. Stable at ~ 55 Gh/s using MinePeon on a Raspberry Pi. Mining Bitcoin with Excel - Duration: 7:17. Knowledge 180,909 views. ... How to generate sha256 hash self-signed certificate using openssl - Duration: 2:31. Gaargi S 14,717 views. My hack job of a mining farm. Nothing fancy, just barebone hashing. It's a hobby Farm now running on a Raspberry B+ I'd love to hear about your rigs! Please comment below and share your links. How To Setup Gekko Science 2Pac USB Mining Bitcoin Algorithm SHA 256 - Duration: 9:29. Little Life 2,840 views. 9:29. The unsolved math problem which could be worth a billion dollars.