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Blockchain Data Format

Developer Reference - Bitcoin

Developer Reference - Bitcoin

BETA: This documentation has not been extensively reviewed by Bitcoin experts and so likely contains numerous errors. Please use the Issue and Edit links on the bottom left menu to help us improve. Click here to close this disclaimer. X The Developer Reference aims to provide technical details and API informationto help you start building Bitcoin-based applications, but it is not aspecification . To make the best use ofthis documentation, you may want to install the current version of BitcoinCore, either from source or from a pre-compiled executable . Questions about Bitcoin development are best asked in one of the Bitcoin development communities .Errors or suggestions related todocumentation on Bitcoin.org can be submitted as an issue or posted to the bitcoin-documentation mailing list . In the following documentation, some strings have been shortened or wrapped: []indicates extra data was removed, and lines ending in a single backslash \are continued below. If you hover your mouse over a paragraph, cross-referencelinks will be shown in blue. If you hover over a cross-reference link, a briefdefinition of the term will be displayed in a tooltip. The Bitcoin.org Developer Documentation describes how Bitcoin works tohelp educate new Bitcoin developers, but it is not a specificationandit never will be. Bitcoin security depends on consensus . Should your program diverge from consensus , its security is weakened or destroyed. The cause of thedivergence doesnt matter: it could be a bug in your program, it couldbe an error in this documentation which youimplemented as described, or it could be you do everything right butother software on the network behaves unexpectedly . The specific cause will not matter to the users of your softwarewhose wealth is lost. The only correct sp Continue reading >>

Blk.dat

Blk.dat

The blk.dat files in ~/.bitcoin/blocks/ contain raw block data received by a bitcoin core node. These blk.dat files basically store "the blockchain ". Every block that your node receives gets appended to a blk.dat file. Also, instead of the entire blockchain being stored in one massive file, they are split in to multiple blk*.dat files. Your node first adds blocks to blk00000.dat, then when it fills up it moves on to blk00001.dat, then blk00002.dat ...and so on. The data in blk.dat files is stored in binary, and each new block gets appended to the end of the file. We can look at the genesis block by reading the first 293 bytes of blk00000.dat: 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 (See the od command below for getting hexadecimal data from a binary file.) The data above can be split in to five pieces: The magic bytes and size allow you to figure out where the data for each block starts and ends. , followed by the transaction data for each one. [ magic bytes ][ size ][ block header ][ tx count ][ transaction data ] <- 4 bytes -> <- 4 bytes -> <- 80 bytes -> <- varint -> <- remainder -> The size field is what allowed me to figure out that I needed to read 293 bytes to get the whole block. The size is given as 1d010000, so get this Continue reading >>

Blocksci: A Platform For Blockchain Science And Exploration

Blocksci: A Platform For Blockchain Science And Exploration

Research and expert commentary on digital technologies in public life BlockSci: a platform for blockchain science and exploration The Bitcoin blockchain currently 140GB and growing contains a massive amount of data that can give us insights into the Bitcoin ecosystem, including how users, businesses, and miners operate. Today were announcing BlockSci , an open-source software tool that enables fast and expressive analysis of Bitcoins and many other blockchains, and an accompanying working paper that explains its design and applications. Our Jupyter notebook demonstrates some of BlockScis capabilities. Current tools for blockchain analysis depend on general-purpose databases that have full support for transactions. But thats unnecessary for blockchain analysis where the data structures are append-only. We take advantage of this observation in the design of our custom in-memory blockchain database as well as an analysis library. BlockScis core infrastructure is written in C++ and optimized for speed. (For example, traversing every transaction input and output on the Bitcoin blockchain takes only 10.3 seconds on our r4.2xlarge EC2 machine.) To make analysis more convenient, we provide Python bindings and a Jupyter notebook interface. This interface is slower, but is ideal for exploratory analyses and allows users to quickly iterate when developing new queries. The code below shows the convenience of traversing the blockchain using straightforward Python idioms, built-in currency conversion using historical exchange-rate data, and the use of pandas DataFrames for analysis and visualization.. fees = [sum(block.fees) for block in chain.range('2017')]times = [block.time for block in chain.range('2017')]converter = blocksci.CurrencyConverter()df = pandas.DataFrame({"Fee":fees} Continue reading >>

Transaction - Bitcoin Wiki

Transaction - Bitcoin Wiki

Byte-map of Transaction with each type of TxIn and TxOut A transaction is a transfer of Bitcoin value that is broadcast to the network and collected into blocks . A transaction typically references previous transaction outputs as new transaction inputs and dedicates all input Bitcoin values to new outputs. Transactions are not encrypted, so it is possible to browse and view every transaction ever collected into a block. Once transactions are buried under enough confirmations they can be considered irreversible . Standard transaction outputs nominate addresses , and the redemption of any future inputs requires a relevant signature. All transactions are visible in the block chain , and can be viewed with a hex editor. A block chain browser is a site where every transaction included within the block chain can be viewed in human-readable terms. This is useful for seeing the technical details of transactions in action and for verifying payments. general format of a Bitcoin transaction (inside a block) if non-zero and sequence numbers are < 0xFFFFFFFF: block height or timestamp when transaction is final Principle example of a Bitcoin transaction with 1 input and 1 output only Input:Previous tx: f5d8ee39a430901c91a5917b9f2dc19d6d1a0e9cea205b009ca73dd04470b9a6Index: 0scriptSig: 304502206e21798a42fae0e854281abd38bacd1aeed3ee3738d9e1446618c4571d1090db022100e2ac980643b0b82c0e88ffdfec6b64e3e6ba35e7ba5fdd7d5d6cc8d25c6b241501Output:Value: 5000000000scriptPubKey: OP_DUP OP_HASH160 404371705fa9bd789a2fcd52d2c580b65d35549dOP_EQUALVERIFY OP_CHECKSIG The input in this transaction imports 50 BTC from output #0 in transaction f5d8... Then the output sends 50 BTC to a Bitcoin address (expressed here in hexadecimal 4043... instead of the normal base58). When the recipient wants to spend this Continue reading >>

3 Parts Of A Blockchain

3 Parts Of A Blockchain

Blockchain vs Database 3 Parts of a Blockchain Factom Software Tokens To understand blockchain, its helpful to think of blockchain in three distinct parts: the block, the chain, and the network.These components are what make up decentralized ledgers. We could explain each piece in great detail, but for this introduction, well walk through each of these three pieces briefly and keep it simple. Block: A block is a time bound collection of data that is published into a ledger entered into the blockchain over a given period. Data is gathered into a block for a set period of time and at the end of the period, the entire block is added to the blockchain. After that a new block is started. The size, period, and triggering event for blocks can vary across blockchains. For example, blocks are entered into the Factom blockchain every 10 minutes, and Ethereum is every 15 seconds. Each block is made up of entries, the smallest piece of data that is stored in the ledger. An entry can be any piece of information that adheres to a format accepted by its ledger. Most blockchains are strict about how entries are written to their ledger, while others like Factom allow users to write anything in a more flexible format. Strict formats are very useful for recording fungible things while flexible formats allow users to store data in a way that is useful for the user for non-fungible things. There is typically a limit on the size of data that can be included in an entry. For larger sets of data, a user can opt to break out the data over multiple entries. This is referred to as linked entries, which is a useful concept when you are thinking about securing data on the blockchain. The simplest way to find an entry in a blockchain is by searching for the hash of the entry in the blockchain. Chai Continue reading >>

Specification Of Blockchain Format

Specification Of Blockchain Format

I'm trying to write a parser for the blockchain, but I can't find a written specification of the format. Does such a thing exist? I don't really fancy reverse engineering it from the data or another parser's source code, but I guess I'll have to if it's not specified. Advertised sites are not endorsed by the Bitcoin Forum. They may be unsafe, untrustworthy, or illegal in your jurisdiction. Advertise here. 0) There's no "blockchain format" for the on-the-disk file. 1) blkNNNN.dat files are simple concatenation of the blocks as seen on the network wire. 2) because of the above and the possibility of Satoshi bitcoin client crashing mid-append, there is a possibility that those files contain partially-written blocks. There will be a header and at least portion of the transaction part written, but not all the way to the end. 3) blkindex.dat is just an index, nothing more. Currently it is in BerkeleyDB but there's a planned switch to LevelDB. None of this matters for your parser because the actual block chain will stay being stored in the above described simple format. 4) If you are trying to write your parser in C++ I suggest first looking into the parser written by the user znort987. Continue reading >>

Let's Build The Tiniest Blockchain

Let's Build The Tiniest Blockchain

Note: This article was originally published to Crypto Currently . Although some think blockchain is a solution waiting for problems, theres no doubt that this novel technology is a marvel of computing. But, what exactly is a blockchain? a digital ledger in which transactions made in bitcoin or another cryptocurrency are recorded chronologically and publicly. > In more general terms, its a public database where new data are stored in a container called a block and are added to an immutable chain (hence blockchain) with data added in the past. In the case of Bitcoin and other cryptocurrencies, these data are groups of transactions. But, the data can be of any type, of course. Blockchain technology has given rise to new, fully digital currencies like Bitcoin and Litecoin that arent issued or managed by a central authority. This brings new freedom to individuals who believe that todays banking systems are a scam or subject to failure. Blockchain has also revolutionized distributed computing in the form of technologies like Ethereum, which has introduced interesting concepts like smart contracts . In this article, Ill make a simple blockchain in less than 50 lines of Python 2 code. Itll be called SnakeCoin. Well start by first defining what our blocks will look like. In blockchain, each block is stored with a timestamp and, optionally, an index. In SnakeCoin, were going to store both. And to help ensure integrity throughout the blockchain, each block will have a self-identifying hash. Like Bitcoin, each blocks hash will be a cryptographic hash of the blocks index, timestamp, data, and the hash of the previous blocks hash. Oh, and the data can be anything you want. import hashlib as hasherclass Block: def __init__(self, index, timestamp, data, previous_hash): self.index = in Continue reading >>

Faq - Recordskeeper, Blockchain-based Record Keeping Solution

Faq - Recordskeeper, Blockchain-based Record Keeping Solution

RecordsKeeper is a Open Public Mineable Blockchain for RecordKeeping & Data Security. It can also be seen as an open source platform for private Blockchains, which offers a rich set of features including extensive configurability, rapid deployment, permissions management, native assets and data streams. You can publish your data in key-value pair format onto the RecordsKeeper Blockchain. Is RecordsKeeper a Storage, Database or Blockchain? RecordsKeeper is a key-value pair based database running on Blockchain. It stores every record as a key-value pair as a part of XRK transaction. In another way you can consider it an amalgamation of all the three (Storage, Database & Blockchain) as it offers storage as a Database over the public Blockchain. How RecordsKeeper is different from traditional storage? Since RecordsKeeper is Public Blockchain it consist of several decentralized nodes (aka Servers) which verify each and every transaction while adding a new Block into the Blockchain. Each node participates in administration: all nodes verify new additions to the blockchain, and are capable of entering new data into the RecordsKeeper. Traditional Database allows the modification of data but with RecordsKeeper Blockchain the data is secured and cannot be tampered, altered or modified once published & confirmed in the RecordsKeeper Blockchain Ledger. How RecordsKeeper is different from Storj, Filecoin and Siacoin? RecordsKeeper is based on simple mechanism to utilize the transaction size to store your data as compared to other 3rd parties which uses rental of Hard Drives of other users to create a network of storage. RecordsKeeper Blockchain is based on Key-Value pairs and reduce the overhead to get space from other parties. RecordsKeeper allows the user to upload data (in key-v Continue reading >>

A Visual Representation Of How To Parse The Bitcoin Blockchain Raw Data : Bitcoin

A Visual Representation Of How To Parse The Bitcoin Blockchain Raw Data : Bitcoin

Do not use URL shortening services: always submit the real link. Begging/asking for bitcoins is absolutely not allowed, no matter how badly you need the bitcoins. Only requests for donations to large, recognized charities are allowed, and only if there is good reason to believe that the person accepting bitcoins on behalf of the charity is trustworthy. News articles that do not contain the word "Bitcoin" are usually off-topic. This subreddit is not about general financial news. Submissions that are mostly about some other cryptocurrency belong elsewhere. For example, /r/CryptoCurrency is a good place to discuss all cryptocurrencies. Promotion of client software which attempts to alter the Bitcoin protocol without overwhelming consensus is not permitted. Trades should usually not be advertised here. For example, submissions like "Buying 100 BTC" or "Selling my computer for bitcoins" do not belong here. /r/Bitcoin is primarily for news and discussion. Please avoid repetition /r/bitcoin is a subreddit devoted to new information and discussion about Bitcoin and its ecosystem. New merchants are welcome to announce their services for Bitcoin, but after those have been announced they are no longer news and should not be re-posted. Aside from new merchant announcements, those interested in advertising to our audience should consider Reddit's self-serve advertising system . Do not post your Bitcoin address unless someone explicitly asks you to. Be aware that Twitter, etc. is full of impersonation. Continue reading >>

Blockchain - Wikipedia

Blockchain - Wikipedia

For other uses, see Block chain (disambiguation) . Blockchain formation. The main chain (black) consists of the longest series of blocks from the genesis block (green) to the current block. Orphan blocks (purple) exist outside of the main chain. A blockchain [1] [2] [3] originally block chain [4] [5] is a continuously growing list of records , called blocks, which are linked and secured using cryptography . [1] [6] Each block typically contains a hash pointer as a link to a previous block, [6] a timestamp and transaction data. [7] By design, blockchains are inherently resistant to modification of the data. Harvard Business Review defines it as "an open, distributed ledger that can record transactions between two parties efficiently and in a verifiable and permanent way." [8] For use as a distributed ledger, a blockchain 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. Blockchains 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 blockchain. [9] This makes blockchains potentially suitable for the recording of events, medical records, [10] [11] and other records management activities, such as identity management , [12] [13] [14] transaction processing , documenting provenance , or food traceability . [15] The first blockchain was conceptualised in 2008 by an anonymous person or group known as Satoshi Nakamoto and implemented in 2009 as a core component of bitcoin where it serves as the public ledger for all transactions. Continue reading >>

What Is The Format Of A Block In The Monero Blockchain?

What Is The Format Of A Block In The Monero Blockchain?

What is the format of a block in the Monero Blockchain? What is in the header? How is the header made? What information about the transactions is present? What is prunable? What part of the block is used for the PoW? Objection, compound! I wonder whether that might be better split in several questions... It's not obviously too broad, though. Kinda on the fence. user36303 Apr 3 '17 at 7:03 Well, I think the only part that is above and beyond a strict use of the word format is the prunable question... but then again, it might not be. It might just be whats the format of a full block and whats the format of a pruned block? You just don't want to spend the time answering :P Ginger Ale Apr 3 '17 at 11:22 block: a set of data (payload) with a block header The structure of a block follows, and it is: The list starts with the number of transaction identifiers that it contains. In Monero source code, it is implemented as the block class. The class inherits the block header class and adds the base transaction body as transaction miner_tx;, and list of transaction identifiers as std::vector tx_hashes;. Each block starts with a block header. The major version defines the block header parsing rules (i.e. block header format) and is incremented with each block header format update. The table below describes version 1 of the block header format. The minor version defines the interpretation details that are not related to block header parsing. It is always safe to parse the block header of a particular major version with a parsing procedure suitable for said version, even if the minor version is unknown. Parsing the block header with an unknown major version is not safe as the content of the block header may be misinterpreted. +---------------+------------------+-------- Continue reading >>

New Venzee Tool Brings Data Transformation And Validation To Your Blockchain Project

New Venzee Tool Brings Data Transformation And Validation To Your Blockchain Project

If the blockchain is going to be an immutable record, you need to start with clean data. The question is, how do you get clean data into a blockchain database to begin with. Its kind of a quandary for use cases not starting with a green field, but Venzee , a startup that has been helping customers clean up their retail supply chain data to share with large vendors, thinks it has an answer. Venzee CEO Kate Hiscox sees this as a data transformation problem, something her company has been working to solve for the past three years in the retail space. That sector is awash in spreadsheets that have to be manually prepared to share with big retailers and their database requirements, she says. Venzee acts as a data transformation layer, taking your spreadsheet information in its current form and helping to convert that data into a format that the big retailers like Amazon and Walmart can use. Its bringing a level of automation, she says has been missing from this industry, one she has worked in for 18 years. If you think about the blockchain, its really just a fancy new database, one where you have to ensure that the data going in is correct or you face having bad data in a system that is supposedly immutable and irrefutable. That would be a real problem. Hiscoxs company has created a product called Mesh to deal with this. Its essentially a data transformation tool for the blockchain that can work for a retail supply chain kind of scenario or other blockchain data transformation requirement and prepare the data to be moved in the appropriate format while providing a data review phase to ensure that its accurate, she says. This involves a three-phase process. In the first, the data is validated, and this is a key phase for blockchain data. In the second its transformed to work Continue reading >>

The Bitcoin Blockchainformat

The Bitcoin Blockchainformat

Posted on August 30, 2016 | Comments Off on The Bitcoin blockchainformat The Bitcoin cryptocurrency depends on security and confidence. If a flaw in the design broke its trust or usability, the whole system would collapse. Its strange, then, that Bitcoin doesnt have a specification. This is considered a feature, not a bug: The Bitcoin.org Developer Documentation describes how Bitcoin works to help educate new Bitcoin developers, but it is not a specificationand it never will be. Bitcoin security depends on consensus. The only correct specification of consensus behavior is the actual behavior of programs on the network which maintain consensus. As that behavior is subject to arbitrary inputs in a large variety of unique environments, it cannot ever be fully documented here or anywhere else. Thats one way to guarantee bug-free code. If the actual behavior is the specification, it cant be wrong. But is that a meaningful spec? Bitcoin is based on blockchain technology. The idea of the blockchain is a distributed, digitally signed ledger. Any transaction is authenticated by the people who engage in it and added to the blockchain. It just keeps growing over time. Each transaction is represented by a block which links back to an earlier block. Bitcoin is supposed to be decentralized, but decentralization in file formats goes with open specifications. Anyone can create an Open Office file, because the spec is public and anyone can write code to check files against it. Proprietary, unpublished formats use the code as the spec, and everyone else has to reverse engineer them. The developer reference actually provides a lot of detail about the blockchain format. However, it contains a strong disclaimer that this documentation has not been extensively reviewed by Bitcoin experts an Continue reading >>

A Gentle Introduction To Blockchaintechnology

A Gentle Introduction To Blockchaintechnology

A gentle introduction to blockchaintechnology This article is a gentle introduction to blockchain technology and assumes minimal technical knowledge. It attempts to describe what it israther thanwhy should I care, which is something for afuture post. A gentle introduction to immutability of blockchains People use the term blockchain technology to mean different things, and it can be confusing. Sometimes they are talking about The Bitcoin Blockchain , sometimes its The Ethereum Blockchain , sometimes its other virtual currenciesor digital tokens , sometimes its smart contracts . Most of the time though, they are talking about distributed ledgers, i.e. a list of transactions that is replicatedacross a number of computers, rather than being stored on a central server. The common themes seem to be a data store which: is replicated across a number of systems in almost real-time usually exists over a peer-to-peer network uses cryptography and digital signatures to prove identity, authenticity and enforce read/write access rights can be read by certain participants, maybe a wider audience, and has mechanisms to make it hard to change historical records, or at least make it easy to detect when someone is trying to do so I see blockchain technology as a collection of technologies, a bit like a bag of Lego. From the bag, you can take out different bricks and put them together in different ways to create different results. I see blockchain technology as a bag of Lego or bricks Whats the difference between a blockchain a a normal database? Very loosely, a blockchain system is a package which containsa normal database plus some software that adds new rows, validates that new rows conform to pre-agreedrules, and listens and broadcasts new rows to its peers across a network, ensuring Continue reading >>

Ethslurp - Drink The Blockchain

Ethslurp - Drink The Blockchain

Download as .zip Download as .tar.gz View on GitHub EthSlurp allows you to export the slurped blockchain data in any format you wish. While it does provide three pre-canned formats (txt, csv, and html), the number of available formats is limitless. This is accomplished through a feature we call 'display strings.' Here's a list of all the fields in an Ethereum transaction: blockHash, blockNumber, confirmations, contractAddress, cumulativeGasUsed, from, gas, gasPrice, gasUsed, hash, input, nonce, timeStamp, to, transactionIndex, value Jumping directly to an example: the display string for exporting a tab seperated text file (.txt) containing the data fields 'timeStamp,' 'from,' and 'value' would look like this: If, instead, you wanted to include 'blocknumber,' 'to,' 'gas,' and 'value,' your display string would look like this: [{BLOCKNUMBER}]\t[{TO}]\t[{GASUSED}]\t[{VALUE}]\n ~2 In display string '1' notice that the tab characters (\t) are outside of the square brackets. A token (that is, everything inside the square brackets) evaluates to empty if the field value (that is, everything inside the squiggly brackets) is empty. Because we want the tab to appear between all fields, empty or not, the tabis outside the ending square brackets. Display string '2' behaves identically. If you wanted comma seperated values (.csv) so you could open the export file directly in MS Excel, you would use: ["{BLOCKNUMBER}"],["{TO}"],["{GASUSED}"],["{VALUE}"]\n ~3 In this case, we've replaced tabs between fields with commas, but we've also placed quotation marks inside the square brackets. If the field value is empty the quotation marks will dissapear. If we had placed the quotation marks outside the square brackets they would appear even if the field was emtpy. While this is not incorrect, Continue reading >>

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