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Ethereum Nonce

Making Sense Of Ethereum Nonce(sense)

Making Sense Of Ethereum Nonce(sense)

Experienced Software Engineer. Senior Android Engineer @ Kik We expect users to send multiple Kin transactions in a row. Were not expecting users to understand blockchain and monitor their transactions manually. When testing our Kin wallet SDK ( Android and iOS ), we witnessed a problem sending multiple transactions one after the other. In a specific period of time, all of our transactions got stuck we couldnt see that they were pending, and eventually they were cancelled. As it turns out, transactions had the same nonce for multiple transactions. Proof of work nonce: A meaningless value in a block that can be adjusted in order to try to satisfy the proof of work condition. This is the essence of mining. This value makes satisfying proof of work hard computational work that depends on luck. Account nonce: A transaction counter in each account that prevents replay attacks . For example, a transaction sending 20 coins from A to B can be repeated over and over by B to continually drain As balance. Our problem is related to the latter nonce the transaction counter. When making a transaction in Ethereum, a consecutive number should be attached to each transaction on the same account. Each node will process transactions from a specific account in a strict order according to the value of its nonce. Therefore, failing to increment this value correctly can result in different kinds of errors. For instance, lets say the latest transaction nonce was 121: Reusing nonce: if we send a new transaction for the same account with a nonce of either 121 or below, the node will reject it. Gaps: if we send a new transaction with a nonce of either 123 or higher, the transaction will not be processed until this gap is closed, i.e. until a transaction with nonce 122 has been processed. As ment Continue reading >>

The Question Of Mining

The Question Of Mining

There are a lot of interesting changes to the Ethereum protocol that are in the works, which will hopefully improve the power of the system, add further features such as light-client friendliness and a higher degree of extensibility, and make Ethereum contracts easier to code. Theoretically, none of these changes are necessary; the Ethereum protocol is fine as it stands today, and can theoretically be released as is once the clients are further built up somewhat; rather, the changes are there to make Ethereum better. However, there is one design objective of Ethereum where the light at the end of the tunnel is a bit further: mining decentralization. Although we always have the backup option of simply sticking with Dagger, Slasher or SHA3, it is entirely unclear that any of those algorithms can truly remain decentralized and mining pool and ASIC-resistant in the long term (Slasher is guaranteed to be decentralized because its proof of stake, but has its own moderately problematic flaws). The basic idea behind the mining algorithm that we want to use is essentially in place; however, as in many cases, the devil is in the details. This version of the Ethereum mining algorithm is a Hashcash-based implementation, similar to Bitcoins SHA256 and Litecoins scrypt; the idea is for the miner to repeatedly compute a pseudorandom function on a block and a nonce, trying a different nonce each time, until eventually some nonce produces a result which starts with a large number of zeroes. The only room to innovate in this kind of implementation is changing the function; in Ethereums case, the rough outline of the function, taking the blockchain state (defined as the header, the current state tree, and all the data of the last 16 blocks), is as follows: Let h[i] = sha3(sha3(block_head Continue reading >>

Ethereum's Memory Hardness Explained, And The Road To Mining It With Custom Hardware

Ethereum's Memory Hardness Explained, And The Road To Mining It With Custom Hardware

Ethereum's Memory Hardness Explained, and the Road to Mining It with Custom Hardware Ethereum's Memory Hardness Explained, and the Road to Mining It with Custom Hardware As crypto-currencies increase in value, so does the payout from mining them. This creates a substantial economic incentive to not only deploy more mining hardware, but to also develop faster, more efficient mining hardware. We saw this with bitcoin: Mining migrated from CPUs, to GPUs, to FPGAs, and now to ASICs [1] . Today, Ethereum GPU mining is the norm, but the miners havent made the jump to running the ethereum mining/hashing algorithm, ethash, on specialized hardware solutions (e.g. FPGAs and ASICs). Plenty of articles and forums attribute this to ethash being memory hard (a.k.a. memory bound ). Here, Ill walk through where Ethereum minings memory hardness comes from, and what the next generation of custom ethereum mining hardware might look like. For this article, Im assuming readers have a general understanding of standard computer technologies and crypto-currency blockchains, but dont need to be programming or mining experts. For a more technical, programmer-oriented explanation of Ethereums mining algorithm, called ethash, please refer to the ethash page on the ethereum wiki . For a less technical introduction to blockchains, visit the blockgeeks blockchain guide here . In proof-of-work mining, miners are tasked with generating a short binary blob (called a nonce), which, when hashed, produces an output value less than a pre-specified target threshold. Due to the cryptographic nature of each currencys hash function, there is no way to reverse-engineer or back-compute a nonce that satisfies the target threshold limit. Instead, miners must guess-and-check hashes as fast as possible, and hope the Continue reading >>

How Ethereum Mining Works

How Ethereum Mining Works

Today, miners play an important role in making sure ethereum works. This role isn't immediately obvious, though. Many new users think that the sole purpose of mining is to generate ethers in a way that doesn't require a central issuer (seeour guide" What is Ether? "). This is true. Ethereum's tokens are created through the process of mining at a rate of 5 ether per mined block. But mining also has another at least asimportant role. Usually, banks are in charge of keeping accurate records of transactions. They ensure that money isn't created out of thin air, and that users don't cheat and spend their money more than once. Blockchains, though, introduce an entirely new way of record-keeping, one where the entire network, rather than an intermediary, verifies transactions and adds them to the public ledger. Although a 'trustless' or 'trust-minimizing' monetary system is the goal, someone still needs to securethe financial records, ensuring that no one cheats. Mining is one innovation that makes decentralized record-keeping possible. Miners come to consensus about the transaction history while preventing fraud (notably the double spending of ethers) an interesting problem that hadnt been solved in decentralized currencies before proof-of-work blockchains. Although ethereum is looking into other methods of coming to consensus about the validity of transactions, mining currently holds the platform together. Today, ethereum's mining process is almost the same as bitcoins . For each block of transactions, miners use computers to repeatedly and very quickly guess answers to a puzzle until one of them wins. More specifically, the miners will run the blocks unique header metadata (including timestamp and software version) through a hash function (which will return a fixed-length, Continue reading >>

Ethereum Block Nonce - Ethereum Eth Commands, Bitcoin Trading Platform Uk, Ethereum Fog Foundation

Ethereum Block Nonce - Ethereum Eth Commands, Bitcoin Trading Platform Uk, Ethereum Fog Foundation

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Glossary Ethereum/wiki Wiki Github

Glossary Ethereum/wiki Wiki Github

See also: Computational infeasibility: a process is computationally infeasible if it would take an impracticably long time (eg. billions of years) to do it for anyone who might conceivably have an interest in carrying it out. Generally, 280 computational steps is considered the lower bound for computational infeasibility. Hash: a hash function (or hash algorithm) is a process by which a piece of data of arbitrary size (could be anything; a piece of text, a picture, or even a list of other hashes) is processed into a small piece of data (usually 32 bytes) which looks completely random, and from which no meaningful data can be recovered about the document, but which has the important property that the result of hashing one particular document is always the same. Additionally, it is crucially important that it is computationally infeasible to find two documents that have the same hash. Generally, changing even one letter in a document will completely randomize the hash; for example, the SHA3 hash of "Saturday" is c38bbc8e93c09f6ed3fe39b5135da91ad1a99d397ef16948606cdcbd14929f9d, whereas the SHA3 hash of Caturday is b4013c0eed56d5a0b448b02ec1d10dd18c1b3832068fbbdc65b98fa9b14b6dbf. Hashes are usually used as a way of creating a globally agreed-upon identifier for a particular document that cannot be forged. Encryption: encryption is a process by which a document (plaintext) is combined with a shorter string of data, called a key (eg. c85ef7d79691fe79573b1a7064c19c1a9819ebdbd1faaab1a8ec92344438aaf4), to produce an output (ciphertext) which can be "decrypted" back into the original plaintext by someone else who has the key, but which is incomprehensible and computationally infeasible to decrypt for anyone who does not have the key. Public key encryption: a special kind of encr Continue reading >>

Ethereum Mining Guide: 2018 Edition

Ethereum Mining Guide: 2018 Edition

The following article was originally published on Reliablecoins website . Mining Ethereum is sorting through data blocks from peer distributed cryptocurrency networks to find information that can be used to solve challenging math problems. Successful Ethereum miners can earn crypotocurrency in in exchange for their work. Ethereum mining requires a lot of intensive computation work, time and lots of processing power. Ethereum is a platform with several applications that are helpful for users trying to do a variety of everyday tasks very simply. Results generated through digital mining is referred to as proof of work system. The process of getting cryptocurrency tokens of Ethereum from blockchain networks requires having computers programmed to run a hashing algorithm non-stop. The hashing algorithm condenses a large amount of information into fixed length string of numbers and letters. Ethash, the hashing algorithm employed by Ethereum, hashes metadata drawn from the most recently available using a nonce. This binary number is able to create a unique hash value. With every new block contained in the blockchain, a new target hash value is set by the network. All miners on that network attempt to guess which nonce will result in the desired value. The miner that discovers the right nonce is awarded the block and receives 5 ether. The process begins again following a cycle which occurs about every 12 seconds. Ethereum Mining Rigs:Dedicated machines can mine ethereum much faster than average computers, but youll need a little bit of help building an efficient mining workhorse like this one. For people interested in doing this type of mining, it is important to get an Ethereum mining how to guide that will walk through every possible step, explain the process in detail and m Continue reading >>

Introduction | Ethereum Frontier Guide

Introduction | Ethereum Frontier Guide

The word mining originates in the context of the gold analogy for crypto currencies. Gold or precious metals are scarce, so are digital tokens, and the only way to increase the total volume is through mining it. This is appropriate to the extent that in Ethereum too, the only mode of issuance post launch is via the mining. Unlike these examples however, mining is also the way to secure the network by creating, verifying, publishing and propagating blocks in the blockchain. Mining Ether = Securing the network = verify computation Ethereum Frontier like all blockchain technologies uses an incentive-driven model of security. Consensus is based on choosing the block with the highest total difficulty. Miners produce blocks which the others check for validity. Among other well-formedness criteria, a block is only valid if it contains proof of work (PoW) of a given difficulty. Note that in Ethereum 1.1, this is likely gonna be replaced by a proof of stake model. [The proof of work algorithm used is called Ethash (a modified version of Dagger-Hashimoto involves finding a nonce input to the algorithm so that the result is below a certain threshold depending on the difficulty. The point in PoW algorithms is that there is no better strategy to find such a nonce than enumerating the possibilities while verification of a solution is trivial and cheap. If outputs have a uniform distribution, then we can guarantee that on average the time needed to find a nonce depends on the difficulty threshold, making it possible to control the time of finding a new block just by manipulating difficulty. The difficulty dynamically adjusts so that on average one block is produced by the entire network every 12 seconds (ie., 12 s block time). This heartbeat basically punctuates the synchronisation o Continue reading >>

Transactions Web3j 3.3.1 Documentation

Transactions Web3j 3.3.1 Documentation

Mining it yourself in a private environment, or the public test environment (testnet) is verystraight forwards. However, in the main live environment (mainnet) it requires significantdedicated GPU time which is not likely to be feasible unless you already have a gaming PC withmultiple dedicated GPUs. If you wish to use a private environment, there is some guidance on the Homestead documentation . To purchase Ether you will need to go via an exchange. As different regions have differentexchanges, you will need to research the best location for this yourself. The Homestead documentation contains a number of exchanges which is a good place to start. There are a number of dedicated test networks in Ethereum, which are supported by various clients. For development, its recommended you use the Rinkeby or Kovan test networks. This is because theyuse a Proof of Authority (PoA) consensus mechanism, ensuring transactions and blocks are created ina consistent and timely manner. The Ropsten testnet, although closest to the Mainnet as it usesProof of Work (PoW) consensus, has been subject to attacks in the past and tends to be moreproblematic for developers. You can request Ether for the Rinkeby testnet via the Rinkeby Crypto Faucet, available at . Details of how to request Ether for the Kovan testnet are available here . If you need some Ether on the Ropsten testnet to get started, please post a message with yourwallet address to the web3j Gitter channel and you will besent some. In the Ethereum test environment (testnet), the mining difficulty is set lower then the mainenvironment (mainnet). This means that you can mine new Ether with a regular CPU, such as yourlaptop. What youll need to do is run an Ethereum client such as Geth or Parity to start buildingup reserves. Further ins Continue reading >>

Convert Bitcoin To Cad - Bitcoin Gold Block Time, Ethereum Nonce Transaction, Bitcoin Price Falling Prediction

Convert Bitcoin To Cad - Bitcoin Gold Block Time, Ethereum Nonce Transaction, Bitcoin Price Falling Prediction

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What Does Each Genesis.json Parameter Mean?

What Does Each Genesis.json Parameter Mean?

nonce A 64-bit hash, which proves, combined with the mix-hash, that a sufficient amount of computation has been carried out on this block: the Proof-of-Work (PoW). The combination of nonce and mixhash must satisfy a mathematical condition described in the Yellowpaper, 4.3.4. Block Header Validity, (44), and allows to verify that the Block has really been cryptographically mined and thus, from this aspect, is valid. The nonce is the cryptographically secure mining proof-of-work that proves beyond reasonable doubt that a particular amount of computation has been expended in the determination of this token value. (Yellowpager, 11.5. Mining Proof-of-Work). timestamp A scalar value equal to the reasonable output of Unix time() function at this block inception. This mechanism enforces a homeostasis in terms of the time between blocks. A smaller period between the last two blocks results in an increase in the difficulty level and thus additional computation required to find the next valid block. If the period is too large, the difficulty, and expected time to the next block, is reduced. The timestamp also allows verifying the order of block within the chain (Yellowpaper, 4.3.4. (43)). mixhash A 256-bit hash which proves, combined with the nonce, that a sufficient amount of computation has been carried out on this block: the Proof-of-Work (PoW). The combination of nonce and mixhash must satisfy a mathematical condition described in the Yellowpaper, 4.3.4. Block Header Validity, (44). It allows to verify that the Block has really been cryptographically mined, thus, from this aspect, is valid. difficulty A scalar value corresponding to the difficulty level applied during the nonce discovering of this block. It defines the mining Target, which can be calculated from the previous Continue reading >>

Cancel Pending Transactions On Ethereum

Cancel Pending Transactions On Ethereum

Oct 9, 2017 00:23 695 words 4 minutes read ethereum pending transaction geth Ethereum transactions model is vastly different from Bitcoin. Instead of using UTXO (unspent transaction outputs)transaction uniqueness and order are achieved using transaction nonce. It is an integer (uint256) counter whichis incremented for each transaction of an account. Its value is effectively the number of transactions sent from a given address andits value must be included in every transaction. transactions must be processed in order (transaction with a nonce of 1 must be processed before the transaction with a nonce of 2) no skipping (transaction with a nonce of 4 cannot be included in a block until transactions with nonces of 1, 2, 3 are processed) This way the network is able to identify duplicates of transactions and enforce their order (which is essential for smart contracts). Each transaction must set gas price which directly affects transaction fees.Miners optimize their profits by including transactions with a high gas price first. If gas price is low the transaction will wait for a long time until it is mined.Eventually, it will be mined (sometimes many hours later) or dropped (miners have limited resources to queue pending transactions).However, even if the transaction is dropped by miners it may still await in pendingTransaction list of your client and artificially increaseyour nonce. You can explore the list of pending transactions on Etherscan . When a transaction is waiting for being mined all subsequent transactions are blocked. They cannot be included in a blockuntil the previous one is included (it is determined by mentioned nonce value). Even if subsequent transactions havea very high gas price they cannot be processed as it would break the order of transactions and pr Continue reading >>

Ethereum Transaction : What Is Nonce ?

Ethereum Transaction : What Is Nonce ?

In Ethereum, every transaction has a nonce. The nonce is the order of transactions sent from a given address. Each time you send a transaction, the nonce increases by 1. There are rules about what transactions are valid transactions and the nonce is used to enforce some of these rules. Specifically: Transactions must be in Order: You cannot have a transaction with a nonce of 1 mined before one with a nonce of 0. No Skipping! You cannot have a transaction with a nonce of 2 mined if you have not already sent transactions with a nonce of 1 and 0. This field prevents double-spends as the nonce is the order the transactions go in. In order for a double-spend to be "successful", you typically... Collect something in return from this first transaction Quickly send another transaction with a high gas price Have this second transaction mined first, therefore invalidating the first transaction. This is why exchanges wait for you to have a certain number of confirmations before allowing you to trade freshly-deposited funds. In Ethereum, this method of "double-spending" is not possible because each transaction has a nonce included with it. Even if you attempt to do the above, it will not work as the second transaction (nonce of 3) cannot be mined before the first transaction (nonce of 2). Continue reading >>

Transactions - What Is Nonce In Ethereum? How Does It Prevent Double Spending? - Ethereum Stack Exchange

Transactions - What Is Nonce In Ethereum? How Does It Prevent Double Spending? - Ethereum Stack Exchange

What is nonce in Ethereum? How does it prevent double spending? recently I got fascinated by blockchain, and started learning Ethereum. I came across Concept of the nonce in Ethereum. After researching I found out that nonce is used for two purposes a. To keep transaction related to an account in order. i.e if there is a transaction with nonce 3 related to some account in the txpool and some transaction will nonce 4 arrived then that transaction won't be mined until and unless transaction with nonce 3 is mined. But I have some question that I am not able to find? i) nonce value is related to an address, right? So two address can have same nonce at the same time i.e. account with Address A can have the latest nonce 2 similarly account with address B can also have latest nonce 2. ii) Do all nodes in the network will have same latest nonce value for all accounts available in the network? That is, if there are three accounts and 2 miners then and nonce value for three accounts are 1,2,3 respectively, then both miner will have the same nonce. b) how is nonce used to prevent a double spend? If you refer the Glossary at Github Wiki , there are two types of nonce used in Ethereum. Account nonce - It's simply the transaction count of an account Proof of work nonce - The random value in a block that was used get the proof of work satisfied (depending on the difficulty at the time). Here you are referring to the account nonce, which is the transaction count from that account. i)Nounce value is related to an address right?So two address can have same nounce at the same time i.e account with Address A can have latest nounce 2 similarly account with address B can also have latest nounce 2. Yes as explained above, it's the transaction count and hence it's related to the account. And Continue reading >>

Creating Offline Ethereum Transactions In Javascript

Creating Offline Ethereum Transactions In Javascript

Creating offline Ethereum transactions in JavaScript By Mikko Ohtamaa a year ago. Tagged under ethereum , javascript , web3 , etherscan . In this blog post we show how to create Ethereum blockchain transactions programmatically in JavaScript and offline. This is the second part of tutorial blog posts continuing the earlier Ethereum JavaScript tutorial left. We bend the meaning of the word offline here a bit. We still communicate with Ethereum network to get the gas cost and the next transaction nonce. However, the private key never leaves the computer. This blog post serves mostly as an example. Advanced users can use the script presented here for doing Ether cold wallet and offline transactions. Target address, either a contract or an Ethereum account. Nonce, incremented once per transaction per account, to prevent double spend attacks. Value, how many Ethers are transferred. Can be 0 for contract calls, but you still need to pay for the gas. The maximum gas the transaction is allowed pull from the sending account. The gas price if the transaction needs a preferential treatment. Optional data payload that would include any function call and arguments encoded. Transaction is signed with the private key of the sending account address. Based on these arguments you can create a raw transaction, as a hex string, that can be pushed to the network. Pushing can happen either through EtherScan.io service or through web3.eth.sendRawTransaction API. Furthermore in this particular example we also need EtherScan.io API key - we use their API to communicate with the network The example script is available on TokenMarket Github repository . Install dependencies with NPM - see previous blog post Please note that this command line monster will go away in the future when Node.js starts Continue reading >>

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