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Bitcoin scriptsig decode

Forth -like, Script is simple, stack-based, and processed from left to right. It is purposefully not Turing-complete, with no loops. A script is essentially a list of instructions recorded with each transaction that describe how the next person wanting to spend the Bitcoins being transferred can gain access to them. The script for a typical Bitcoin transfer to destination Bitcoin address D simply encumbers future spending of the bitcoins with two things: the spender must provide a public key that, when hashed, yields destination address D embedded in the script, and a signature to show evidence of the private key corresponding to the public key just provided. Scripting provides the flexibility to change the parameters of what's needed to spend transferred Bitcoins. For example, the scripting system could be used to require two private keys, or a combination of several, or even no keys at all. A transaction is valid if nothing in the combined script triggers failure and the top stack item is true (non-zero). The party who originally sent the Bitcoins now being spent, dictates the script operations that will occur last in order to release them for use in another transaction. The party wanting to spend them must provide the input(s) to the previously recorded script that results in those operations occurring last leaving behind true (non-zero). Officially Bitcoin script is defined by its reference implementation . When used as numbers, byte vectors are interpreted as little-endian variable-length integers with the most significant bit determining the sign of the integer. Thus 0x81 represents -1.0x80 is another representation of zero (so called neg Continue reading Deconstructing Bitcoin Transactions Part 1 Example 1. Pay-to-Public-Key-Hash (P2PKH) - One-to-one Transaction The majority of Bitcoin transactions today are of this general type. These types of transactions are used to transfer value, typically from one user to another. They are constructed having the form: script Sig (or the unlocking script) first, followed by the script Pub Key (or locking script). This example transfers the complete value from one Unspent Transaction Output (UTXO) into one address. Note: For simplification purposes, this example does not take into account a miners fee, and would most likely take additional time to be incorporated into the block chain. However, we are using the testnet where mining fees are not as strict. UTXO: 219f4b02e6e67dfbb27601449eec399f112fd3d49314aeacf63cbc5cac72c496 Pub Key: 0207c9ece04a9b5ef3ff441f3aad6bb63e323c05047a820ab45ebbe61385aa7446 Total Initial Value: 0 Satoshi (to Begin) Hover over each section of the script to see what they are. 01000000The version in Little-Endian (reversed) format 01The number of input(s)/UTXO(s) 96c472ac5cbc3cf6acae1493d4d32f119f39ec9e440176b2fb7de6e6024b9f21Previous transaction output hash, in Little-Endian. This can be found in the transaction input (txid) from your block explorer such as 01000000Output index output_no of the previous transaction in Little-Endian format. 6a The size (bytes) of the script Sig or Unlocking Script that immediately follows. 3044022034519a85fb5299e180865dda936c5d53edabaaf6d15cd1740aac9878b76238e002207345fcb5a62deeb8d9d80e5b412bd24d09151c2008b7f Continue reading Advertised sites are not endorsed by the Bitcoin Forum. block hash: 000000000000034a7dedef4a161fa058a2d67a173a90155f3a2fe6fc132e0ebf 0.0495 BTC (U) 1PQtw AZpv52PS9kgdsdd6h LHN9SCrv15UV Output is unspent 0.95 BTC (S) 1Bjuaz Xd6p Bt Zpv DXwm76dueoi NJf XLj1p No addresses in raw data. At start each script is empty or is stuff of previous script? block raw: 0100000001a7c3e111fcf6acf6d14a5ec90faedf03ba5fe589069a48113cddd3a43a866c4901000 0006a473044022050c91af9918b85525ebf8802d69a904e85abe6dee306201689107c63a41e7ae2 02206faa2bb6a4073f78672364db85bce6022686c5b604f789d9b9b6383d1086bc830121031d4a1 0c5ae03e291aaf1fced54b1848535fbd926b671726297dd3455c399d380ffffffff02f0874b0000 0000001976a914f5d7afc3df015ecfd309dd591acf1b8f1e0c4ec088acc095a905000000001976a 91475ce9ff7867baffecbb0e61f879bab9e976e9c1488ac00000000 For the output addresses, find the script_pub_key. This value is in HEX as are all similar numbers and need to convert HEX to DEC to be human readable. They may be unsafe, untrustworthy, or illegal in your jurisdiction. Is doc but i don't want proceed full interpretation, but find addresses. If you follow the instructions in the links you posted you should get 76a914f5d7afc3df015ecfd309dd591acf1b8f1e0c4ec088ac for the first output. Now this is a standard pay to pubkey hash script that decodes as: OP_DUP OP_HASH160 f5d7afc3df015ecfd309dd591acf1b8f1e0c4ec0 OP_EQUALVERIFY OP_CHECKSIG So the hex number is the 160 bit hash of the public key. Follow the instructions on (starting at step 4) to get the address in base58 encoding. For the input, you can either take the script_pub_key from the previous transactioon, or extract the pubkey from the input script (the second pushed number), which in this c Continue reading Block Parsers: How to Read the Bitcoin Block Chain Join our community of 10 000 traders on for just per month. There is no encryption of the data stored in the block chain. Meaning, ECDSA key pairs are used to abstract the identity of users. However, the binary data in the block chain can be read. Every full node participating in the Bitcoin network has the same copy. The Bitcoin protocol dictates its structure and is the means through which each node maintains a duplicate copy. In all, 138 lines of Python code are used to build this block parser. Overall, the block chain is just a data structure for storing blocks . In some places, encoding and endianness are unfamiliar or backwards. The block chain stores blocks in a series, beginning with the genesis block . Despite these minor formatting issues, below is a beginner approach to a Bitcoin block parser. The project began with building the tools required to parse the binary data. The protocol dictates the tools that will be necessary. import structdef uint1(stream):return ord(stream.read(1))def uint2(stream):return struct.unpack('H', stream.read(2))[0]def uint4(stream):return struct.unpack('I', stream.read(4))[0]def uint8(stream):return struct.unpack('Q', stream.read(8))[0]def hash32(stream):return stream.read(32)[::-1]def time(stream):time = uint4(stream)return timedef varint(stream):size = uint1(stream)if size I told you what a script is, but not exactly what its needed for. By the way, in the article about transaction processing I gave you an overview of how bitcoins move around by introducing transaction inputs and outputs. So far, we learned that a script is a piece of code that executes and yields a result. When building a transaction from an unspent transaction output (UTXO), there are two scripts were particularly interested in: The problem is producing such an IS that the concatenated script VS = IS OS (the validation script), after being executed, returns a non-zero value. With this in mind, the validation script decides if the transaction input has right to spend the previous unspent output. Now join them to have the following validation script: Fine, the validation script ends with 1 (OP_TRUE) on the stack, so the input script can spend the previous output script. In fact, many other input scripts comply, like: See how anybody with some basic math knowledge could easily steal the output coins. Conversely, look at this very simple output script: No matter the input script, the validation script will never succeed. Any bitcoin sent to this output will be lost forever. In fact, all the above scripts are dangerous and would be rejected by Mainnet for not being standard. Miners dont accept transactions with non-standard scripts because in many situations they may result in money loss, directly or indirectly. Virtually any kind of script can be included in a transaction. Still, only standard scripts will be accepted by Mainnet miners for security reasons. The standard term comes from the Is Standard check, a piece of code from Bitcoin Core ensuring that a script matches one of several wel Continue reading Simple utility methods to convert bytes into the hex-encoded strings or to and from little-endian numbers. var hex = ;var little Endian = ; Bitcoin addresses are encoded using the base-58 encoding as it offers human-friendly output . The implementation below uses a big integer library. var base58 = { _codes: '123456789ABCDEFGHJKLMNPQRSTUVWXYZ' 'abcdefghijkmnopqrstuvwxyz', _58: new Big Integer('58'), encode: function(bytes) , decode: function(string) { var result = Big Integer. ZERO; var output = [], code, power; for (var i = 0; i Well not quite all the way; but the process described here is manual enough for my purpose. The goal is to know the makeup of transactions in enough detail so as to allow us to understand the issue of transaction malleability, and the proposed fixes for this bug. What I want to accomplish in this post is a sufficiently deep dive into how transactions work and how they are put together while avoiding the use of tools like Bitcoin libraries and the reference client wherever they abstract over certain pertinent details. Lets get back to our simple single input, single output transaction. Figure 1: The P2PKH transaction well build in this article. Figure 1, the same figure you saw in Part 1, illustrates the structure of a typical P2PKH transaction. In fact, this figure represents the end result of our effort to build a transaction by hand. Throughout this Part 2, we will go through all the steps that eventually lead us to the raw transaction data structure depicted in Figure 1. Step 1: Building the Transaction, Minus the script Sig Entering the Outpoint and Other Standard Fields The Input segment has two functions. First, it identifies the Output of a previous transaction that we intend to spend in the current transaction. Second, it holds the script Sig that will unlock the script Pub Key of that Output. The first field specifies the transaction hash (transaction ID) of that previous transaction which contains the Output we now want to spend. The second field specifies the Index of that output. Together, these two fields are referred to as the outpoint. The previous transaction whose Output we want to spend can be called the funding transaction. For our example, I am using the following transaction as our funding transaction: If you clic Continue reading 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. X The following guide aims to provide examples to help you startbuilding Bitcoin-based applications. To make the best use of this document,you may want to install the current version of Bitcoin Core, either from source or from a pre-compiled executable . Once installed, youll have access to three programs: bitcoind,bitcoin-qt, and bitcoin-cli. bitcoin-qt provides a combination full Bitcoin peer and wallet frontend. From the Help menu, you can access a console where you canenter the RPC commands used throughout this document. bitcoind is more useful for programming: it provides a full peer which you can interact with through RPCs to port 8332 (or 18332for testnet ). bitcoin-cli allows you to send RPC commands to bitcoind from thecommand line. For example, bitcoin-cli help All three programs get settings from in the Bitcoinapplication directory: OSX: $HOME/Library/Application Support/Bitcoin/ To use bitcoind and bitcoin-cli, you will need to add a RPC passwordto your file. Both programs will read from the same fileif both run on the same system as the same user, so any long randompassword will work: rpcpassword=change_this_to_a_long_random_password You should also make the file only readable to itsowner. On Linux, Mac OSX, and other Unix-like systems, this can beaccomplished by running the following command in the Bitcoin applicationdirectory: For development, its safer and cheaper to use Bitcoins test network ( testnet )or regression test mode ( regtest ) described below. Questions about Bitcoin use a Continue reading If you clicked the button above, then you are currently mining bitcoin, the math-based digital currency that recently topped S,000 on exchanges. (It wont do anything bad to your computer, we promise.) New bitcoins are created roughly every 10 minutes in batches of 25 coins, with each coin worth around 0 at current rates. Your computerin collaboration with those of everyone else reading this post who clicked the button aboveis racing thousands of others to unlock and claim the next batch. For as long as that counter above keeps climbing, your computer will keep running a bitcoin mining script and trying to get a piece of the action. (But dont worry: Its designed to shut off after 10 minutes if you are on a phone or a tablet, so your battery doesnt drain). Your computer is not blasting through the cavernous depths of the internet in search of digital ore that can be fashioned into bitcoin bullion. There is no ore, and bitcoin mining doesnt involve extracting or smelting anything. Its called mining only because the people who do it are the ones who get new bitcoins, and because bitcoin is a finite resource liberated in small amounts over time, like gold, or anything else that is mined. (The size of each batch of coins drops by half roughly every four years, and around 2140, it will be cut to zero, capping the total number of bitcoins in circulation at 21 million.) But the analogy ends there. What bitcoin miners actually do could be better described as competitive bookkeeping. Miners build and maintain a gigantic public ledger containing a record of every bitcoin transaction in history. Every time somebody wants to send bitcoins to somebody else, the transfer has to be validated by miners: They check the ledger to ma Continue reading # Copyright (C) 2012-2014 The python-bitcoinlib developers## This file is part of python-bitcoinlib.## It is subject to the license terms in the LICENSE file found in the top-level# directory of this distribution.## No part of python-bitcoinlib, including this file, may be copied, modified,# propagated, or distributed except according to the terms contained in the# LICENSE file."""Scripts Functionality to build scripts, as well as Signature Hash(). Script evaluationis in scripteval"""from __future__ import absolute_import, division, print_function, unicode_literalsimport sysbchr = chrbord = ordif sys.version '3': long = int bchr = lambda x: bytes([x]) bord = lambda x: ximport copyimport structimport bitcoin.coreimport bignum MAX_SCRIPT_SIZE = 10000MAX_SCRIPT_ELEMENT_SIZE = 520MAX_SCRIPT_OPCODES = 201OPCODE_NAMES = _opcode_instances = [] [docs] class CScript Op(int): """A single script opcode""" __slots__ = [] @staticmethod [docs] def encode_op_pushdata(d): """Encode a PUSHDATA op, returning bytes""" if len(d) How to fully decode a coinbase transaction? After reading this What is the format of the coinbase transaction? decoderawtransaction of a random Litecoin coinbase transaction: "coinbase" : "038abd07062f503253482f048725ee5208083865a409000000092f7374726174756d2f",... Is that all I can do if I don't know how the pool operator has structured the coinbase? "script Pub Key" : { "asm" : "OP_DUP OP_HASH160 975efcba1e058667594dc57146022ec46560a63c OP_EQUALVERIFY OP_CHECKSIG", "hex" : "76a914975efcba1e058667594dc57146022ec46560a63c88ac",.. Continue reading Rusty is a Linux kernel dev who wandered into Blockstream, and is currently trying to produce a prototype and spec for bitcoin lightning. OK, now Ive fully converted c-lightning to use segregated witness (which open-codes all the bitcoin transactions), Ive jotted down a few signposts for other developers looking at segregated witness support in their clients. I added a u8** witness to my struct bitcoin_tx for ease of encoding, with NULL meaning no witness. "addresses" : [ "LZ2L61M8r Co Zm K7Sem TBqfxu FZv5Uj4pe R" Is the asm field the outgoing address? This is not bitcoin script, but the raw stack data from bottom to top. If yes how is it encoded and what is the hex field for? So whereas you might have previously had a script Sig for a multisig P2SH of OP_0 PUSH(sig1) PUSH(sig2) PUSH(redeemscript) your equivalent witness is the stack that results, ie [] [sig1] [sig2] [redeemscript] which gets encoded as simply as possible: a varint for the number of items (ie. Same question goes for script Sig asm field in a normal transaction. 3 here), then a varint length followed by the item for each one. It contains the public key and the signature but how is it structured/encoded. And note that OP_0 pushes an empty element on the stack, not a zero byte! Because I have a Tx with to vins from the same address and I don't see the same public key in the asm field. BIP 141 : The basic Segregated Witness BIP is pretty dense, but youll need to read it. In particular, youll need to write new encode/decode routines for transactions with witnesses (which are made to look like transactions with no inputs, normally invalid). Fortunately, this is fairly easy, and has a flags field for future extensions; see add_tx() . BIP 143 : You need to write a new serializer for your transactions for any signatures youre going to put inside a witness; OP_CHECKSIG works differently! parses and displays data that our industry peers deem unparsable. The BIP is pretty clear, but you can also see tx.c which has a self-contained hash_for_segwit() if you just want SIGHASH_ALL support. During the course of my work at Blockchain Intelligence Group I routinely run different analyses on the Bitcoin blockchain. Fee estimation: presumably the semantics of bitcoins estimatefee RPC call wont change, which means you should create a routi Continue reading Public block explorers do not correctly parse and display all transaction data. G.) takes data integrity seriously, we routinely make sure that even edge-cases are taken care of. In order to minimize errors i frequently compare our data versus that of public blockchain explorers. Some multisig scripts are not decoded properly even by the most used public block explorer. At one point I was looking into multi-signature transactions, and I discovered something interesting. For those who are not familiar with multisig transactions, I will first present a quick multisig summary here. A multisig transaction is one in which the funds are sent to a special multisig address (also called P2SH Pay to Script Hash). The difference between a simple and a multisig address is the number of signatures it takes to redeem an output. With simple addresses (P2PKH Pay To Pub Key Hash), the signature required to redeem an output previously sent to that address is the one of the address itself. Multisig addresses can have a number of signatories required to redeem an output. When creating a multisig address we can specify the number of signatures required (we can look this up in our bitcoin wallet by typing help addmultisigaddress into the console of the debug window). We also specify all the addresses that can sign for outputs sent to this newly created multisig address. So we have n signatures required and m number of addresses eligible to sign, thats why often you see the n out of m phrase associated with multisignature addresses. I have created a vanity address Continue reading All bitcoin transactions have scripts embedded into its inputs and outputs. The scripts use a very simple programming language, which is evaluated from left to right using a stack. The language is designed such that it guarantees all scripts will execute in a limited amount of time (it is not Turing-Complete). When a transaction is validated, the input scripts are concatenated with the output scripts and evaluated. To be valid, all transaction scripts must evaluate to true. A good analogy for how this works is that the output scripts are puzzles that specify in which conditions can those bitcoins be spent. The input scripts provide the correct data to make those output scripts evaluate to true. For more detailed information about the bitcoin scripting language, check the online reference on bitcoin's wiki . The Script object provides an interface to construct, parse, and identify bitcoin scripts. It also gives simple interfaces to create most common script types. This class is useful if you want to create custom input or output scripts. In other case, you should probably use Transaction. Here's how to use Script to create the five most common script types: This is the most commonly used transaction output script. It's used to pay to a bitcoin address (a bitcoin address is a public key hash encoded in base58check) // create a new p2pkh paying to a specific addressvar address = String('1Na TVw XDDUJa XDQajoa9Mq Hhz4u Txtg K14');var script = Script.build Public Key Hash Out(address);assert(String() === 'OP_DUP OP_HASH160 20 0xecae7d092947b7ee4998e254aa48900d26d2ce1d OP_EQUALVERIFY OP_CHECKSIG'); Pay to public key scripts are a simplified form of the p2pkh, but aren't commonly used in new transactions anymore, because p2pkh scripts are more secure (the public ke Continue reading A Bitcoin lives as code inside a computer. Chances are you have never used a Bitcoin, but youve probably heard of it. The virtual currency is popping up more and more in the news and the government has been showing an increased interest in the subject. For instance, the top Democrat and Republican on the Senates Homeland Security and Governmental Affairs Committee this week told federal financial regulators and law enforcement officials to explain how they are keeping tabs on virtual currencies, including the S.2 billion market for Bitcoins. What follows is guide to understanding the currency, why its used and why the government is paying attention. At its most basic level a Bitcoin is a form of money that can be used to pay for products or services just like the dollar bills that sit in your wallet. Its intangible, but it works in many ways like cold, hard cash. To acquire a Bitcoin, you need to buy it with another currency or have someone send it to you in a transaction. To hold a Bitcoin, you need to keep it in a digital wallet, a piece of software, on your local computer or you can you can allow a company to hold your wallet on their servers. Bitcoin payments are made by transferring the digital currency between two users wallets. The fees for these transfers are lower than for more traditional forms of payments, like using a credit card or a bank transfer, because they are not backed by the safeguards and intermediary services provided by companies like Visa or Bank of America. Forth -like, Script is simple, stack-based, and processed from left to right. It is purposefully not Turing-complete, with no loops. A script is essentially a list of instructions recorded with each transaction that describe how the next person wanting to spend the Bitcoins being transferred can gain access to them. The script for a typical Bitcoin transfer to destination Bitcoin address D simply encumbers future spending of the bitcoins with two things: the spender must provide a public key that, when hashed, yields destination address D embedded in the script, and a signature to show evidence of the private key corresponding to the public key just provided. Scripting provides the flexibility to change the parameters of what's needed to spend transferred Bitcoins. For example, the scripting system could be used to require two private keys, or a combination of several, or even no keys at all. A transaction is valid if nothing in the combined script triggers failure and the top stack item is true (non-zero). The party who originally sent the Bitcoins now being spent, dictates the script operations that will occur last in order to release them for use in another transaction. The party wanting to spend them must provide the input(s) to the previously recorded script that results in those operations occurring last leaving behind true (non-zero). Officially Bitcoin script is defined by its reference implementation . When used as numbers, byte vectors are interpreted as little-endian variable-length integers with the most significant bit determining the sign of the integer. Thus 0x81 represents -1.0x80 is another representation of zero (so called neg Continue reading Deconstructing Bitcoin Transactions Part 1 Example 1. Pay-to-Public-Key-Hash (P2PKH) - One-to-one Transaction The majority of Bitcoin transactions today are of this general type. These types of transactions are used to transfer value, typically from one user to another. They are constructed having the form: script Sig (or the unlocking script) first, followed by the script Pub Key (or locking script). This example transfers the complete value from one Unspent Transaction Output (UTXO) into one address. Note: For simplification purposes, this example does not take into account a miners fee, and would most likely take additional time to be incorporated into the block chain. However, we are using the testnet where mining fees are not as strict. UTXO: 219f4b02e6e67dfbb27601449eec399f112fd3d49314aeacf63cbc5cac72c496 Pub Key: 0207c9ece04a9b5ef3ff441f3aad6bb63e323c05047a820ab45ebbe61385aa7446 Total Initial Value: 0 Satoshi (to Begin) Hover over each section of the script to see what they are. 01000000The version in Little-Endian (reversed) format 01The number of input(s)/UTXO(s) 96c472ac5cbc3cf6acae1493d4d32f119f39ec9e440176b2fb7de6e6024b9f21Previous transaction output hash, in Little-Endian. This can be found in the transaction input (txid) from your block explorer such as 01000000Output index output_no of the previous transaction in Little-Endian format. 6a The size (bytes) of the script Sig or Unlocking Script that immediately follows. 3044022034519a85fb5299e180865dda936c5d53edabaaf6d15cd1740aac9878b76238e002207345fcb5a62deeb8d9d80e5b412bd24d09151c2008b7f Continue reading Advertised sites are not endorsed by the Bitcoin Forum. block hash: 000000000000034a7dedef4a161fa058a2d67a173a90155f3a2fe6fc132e0ebf 0.0495 BTC (U) 1PQtw AZpv52PS9kgdsdd6h LHN9SCrv15UV Output is unspent 0.95 BTC (S) 1Bjuaz Xd6p Bt Zpv DXwm76dueoi NJf XLj1p No addresses in raw data. At start each script is empty or is stuff of previous script? block raw: 0100000001a7c3e111fcf6acf6d14a5ec90faedf03ba5fe589069a48113cddd3a43a866c4901000 0006a473044022050c91af9918b85525ebf8802d69a904e85abe6dee306201689107c63a41e7ae2 02206faa2bb6a4073f78672364db85bce6022686c5b604f789d9b9b6383d1086bc830121031d4a1 0c5ae03e291aaf1fced54b1848535fbd926b671726297dd3455c399d380ffffffff02f0874b0000 0000001976a914f5d7afc3df015ecfd309dd591acf1b8f1e0c4ec088acc095a905000000001976a 91475ce9ff7867baffecbb0e61f879bab9e976e9c1488ac00000000 For the output addresses, find the script_pub_key. This value is in HEX as are all similar numbers and need to convert HEX to DEC to be human readable. They may be unsafe, untrustworthy, or illegal in your jurisdiction. Is doc but i don't want proceed full interpretation, but find addresses. If you follow the instructions in the links you posted you should get 76a914f5d7afc3df015ecfd309dd591acf1b8f1e0c4ec088ac for the first output. Now this is a standard pay to pubkey hash script that decodes as: OP_DUP OP_HASH160 f5d7afc3df015ecfd309dd591acf1b8f1e0c4ec0 OP_EQUALVERIFY OP_CHECKSIG So the hex number is the 160 bit hash of the public key. Follow the instructions on (starting at step 4) to get the address in base58 encoding. For the input, you can either take the script_pub_key from the previous transactioon, or extract the pubkey from the input script (the second pushed number), which in this c Continue reading Block Parsers: How to Read the Bitcoin Block Chain Join our community of 10 000 traders on for just per month. There is no encryption of the data stored in the block chain. Meaning, ECDSA key pairs are used to abstract the identity of users. However, the binary data in the block chain can be read. Every full node participating in the Bitcoin network has the same copy. The Bitcoin protocol dictates its structure and is the means through which each node maintains a duplicate copy. In all, 138 lines of Python code are used to build this block parser. Overall, the block chain is just a data structure for storing blocks . In some places, encoding and endianness are unfamiliar or backwards. The block chain stores blocks in a series, beginning with the genesis block . Despite these minor formatting issues, below is a beginner approach to a Bitcoin block parser. The project began with building the tools required to parse the binary data. The protocol dictates the tools that will be necessary. import structdef uint1(stream):return ord(stream.read(1))def uint2(stream):return struct.unpack('H', stream.read(2))[0]def uint4(stream):return struct.unpack('I', stream.read(4))[0]def uint8(stream):return struct.unpack('Q', stream.read(8))[0]def hash32(stream):return stream.read(32)[::-1]def time(stream):time = uint4(stream)return timedef varint(stream):size = uint1(stream)if size I told you what a script is, but not exactly what its needed for. By the way, in the article about transaction processing I gave you an overview of how bitcoins move around by introducing transaction inputs and outputs. So far, we learned that a script is a piece of code that executes and yields a result. When building a transaction from an unspent transaction output (UTXO), there are two scripts were particularly interested in: The problem is producing such an IS that the concatenated script VS = IS OS (the validation script), after being executed, returns a non-zero value. With this in mind, the validation script decides if the transaction input has right to spend the previous unspent output. Now join them to have the following validation script: Fine, the validation script ends with 1 (OP_TRUE) on the stack, so the input script can spend the previous output script. In fact, many other input scripts comply, like: See how anybody with some basic math knowledge could easily steal the output coins. Conversely, look at this very simple output script: No matter the input script, the validation script will never succeed. Any bitcoin sent to this output will be lost forever. In fact, all the above scripts are dangerous and would be rejected by Mainnet for not being standard. Miners dont accept transactions with non-standard scripts because in many situations they may result in money loss, directly or indirectly. Virtually any kind of script can be included in a transaction. Still, only standard scripts will be accepted by Mainnet miners for security reasons. The standard term comes from the Is Standard check, a piece of code from Bitcoin Core ensuring that a script matches one of several wel Continue reading Simple utility methods to convert bytes into the hex-encoded strings or to and from little-endian numbers. var hex = ;var little Endian = ; Bitcoin addresses are encoded using the base-58 encoding as it offers human-friendly output . The implementation below uses a big integer library. var base58 = { _codes: '123456789ABCDEFGHJKLMNPQRSTUVWXYZ' 'abcdefghijkmnopqrstuvwxyz', _58: new Big Integer('58'), encode: function(bytes) , decode: function(string) { var result = Big Integer. ZERO; var output = [], code, power; for (var i = 0; i Well not quite all the way; but the process described here is manual enough for my purpose. The goal is to know the makeup of transactions in enough detail so as to allow us to understand the issue of transaction malleability, and the proposed fixes for this bug. What I want to accomplish in this post is a sufficiently deep dive into how transactions work and how they are put together while avoiding the use of tools like Bitcoin libraries and the reference client wherever they abstract over certain pertinent details. Lets get back to our simple single input, single output transaction. Figure 1: The P2PKH transaction well build in this article. Figure 1, the same figure you saw in Part 1, illustrates the structure of a typical P2PKH transaction. In fact, this figure represents the end result of our effort to build a transaction by hand. Throughout this Part 2, we will go through all the steps that eventually lead us to the raw transaction data structure depicted in Figure 1. Step 1: Building the Transaction, Minus the script Sig Entering the Outpoint and Other Standard Fields The Input segment has two functions. First, it identifies the Output of a previous transaction that we intend to spend in the current transaction. Second, it holds the script Sig that will unlock the script Pub Key of that Output. The first field specifies the transaction hash (transaction ID) of that previous transaction which contains the Output we now want to spend. The second field specifies the Index of that output. Together, these two fields are referred to as the outpoint. The previous transaction whose Output we want to spend can be called the funding transaction. For our example, I am using the following transaction as our funding transaction: If you clic Continue reading 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. X The following guide aims to provide examples to help you startbuilding Bitcoin-based applications. To make the best use of this document,you may want to install the current version of Bitcoin Core, either from source or from a pre-compiled executable . Once installed, youll have access to three programs: bitcoind,bitcoin-qt, and bitcoin-cli. bitcoin-qt provides a combination full Bitcoin peer and wallet frontend. From the Help menu, you can access a console where you canenter the RPC commands used throughout this document. bitcoind is more useful for programming: it provides a full peer which you can interact with through RPCs to port 8332 (or 18332for testnet ). bitcoin-cli allows you to send RPC commands to bitcoind from thecommand line. For example, bitcoin-cli help All three programs get settings from in the Bitcoinapplication directory: OSX: $HOME/Library/Application Support/Bitcoin/ To use bitcoind and bitcoin-cli, you will need to add a RPC passwordto your file. Both programs will read from the same fileif both run on the same system as the same user, so any long randompassword will work: rpcpassword=change_this_to_a_long_random_password You should also make the file only readable to itsowner. On Linux, Mac OSX, and other Unix-like systems, this can beaccomplished by running the following command in the Bitcoin applicationdirectory: For development, its safer and cheaper to use Bitcoins test network ( testnet )or regression test mode ( regtest ) described below. Questions about Bitcoin use a Continue reading If you clicked the button above, then you are currently mining bitcoin, the math-based digital currency that recently topped S,000 on exchanges. (It wont do anything bad to your computer, we promise.) New bitcoins are created roughly every 10 minutes in batches of 25 coins, with each coin worth around 0 at current rates. Your computerin collaboration with those of everyone else reading this post who clicked the button aboveis racing thousands of others to unlock and claim the next batch. For as long as that counter above keeps climbing, your computer will keep running a bitcoin mining script and trying to get a piece of the action. (But dont worry: Its designed to shut off after 10 minutes if you are on a phone or a tablet, so your battery doesnt drain). Your computer is not blasting through the cavernous depths of the internet in search of digital ore that can be fashioned into bitcoin bullion. There is no ore, and bitcoin mining doesnt involve extracting or smelting anything. Its called mining only because the people who do it are the ones who get new bitcoins, and because bitcoin is a finite resource liberated in small amounts over time, like gold, or anything else that is mined. (The size of each batch of coins drops by half roughly every four years, and around 2140, it will be cut to zero, capping the total number of bitcoins in circulation at 21 million.) But the analogy ends there. What bitcoin miners actually do could be better described as competitive bookkeeping. Miners build and maintain a gigantic public ledger containing a record of every bitcoin transaction in history. Every time somebody wants to send bitcoins to somebody else, the transfer has to be validated by miners: They check the ledger to ma Continue reading # Copyright (C) 2012-2014 The python-bitcoinlib developers## This file is part of python-bitcoinlib.## It is subject to the license terms in the LICENSE file found in the top-level# directory of this distribution.## No part of python-bitcoinlib, including this file, may be copied, modified,# propagated, or distributed except according to the terms contained in the# LICENSE file."""Scripts Functionality to build scripts, as well as Signature Hash(). Script evaluationis in scripteval"""from __future__ import absolute_import, division, print_function, unicode_literalsimport sysbchr = chrbord = ordif sys.version '3': long = int bchr = lambda x: bytes([x]) bord = lambda x: ximport copyimport structimport bitcoin.coreimport bignum MAX_SCRIPT_SIZE = 10000MAX_SCRIPT_ELEMENT_SIZE = 520MAX_SCRIPT_OPCODES = 201OPCODE_NAMES = _opcode_instances = [] [docs] class CScript Op(int): """A single script opcode""" __slots__ = [] @staticmethod [docs] def encode_op_pushdata(d): """Encode a PUSHDATA op, returning bytes""" if len(d) How to fully decode a coinbase transaction? After reading this What is the format of the coinbase transaction? decoderawtransaction of a random Litecoin coinbase transaction: "coinbase" : "038abd07062f503253482f048725ee5208083865a409000000092f7374726174756d2f",... Is that all I can do if I don't know how the pool operator has structured the coinbase? "script Pub Key" : { "asm" : "OP_DUP OP_HASH160 975efcba1e058667594dc57146022ec46560a63c OP_EQUALVERIFY OP_CHECKSIG", "hex" : "76a914975efcba1e058667594dc57146022ec46560a63c88ac",.. Continue reading Rusty is a Linux kernel dev who wandered into Blockstream, and is currently trying to produce a prototype and spec for bitcoin lightning. OK, now Ive fully converted c-lightning to use segregated witness (which open-codes all the bitcoin transactions), Ive jotted down a few signposts for other developers looking at segregated witness support in their clients. I added a u8** witness to my struct bitcoin_tx for ease of encoding, with NULL meaning no witness. "addresses" : [ "LZ2L61M8r Co Zm K7Sem TBqfxu FZv5Uj4pe R" Is the asm field the outgoing address? This is not bitcoin script, but the raw stack data from bottom to top. If yes how is it encoded and what is the hex field for? So whereas you might have previously had a script Sig for a multisig P2SH of OP_0 PUSH(sig1) PUSH(sig2) PUSH(redeemscript) your equivalent witness is the stack that results, ie [] [sig1] [sig2] [redeemscript] which gets encoded as simply as possible: a varint for the number of items (ie. Same question goes for script Sig asm field in a normal transaction. 3 here), then a varint length followed by the item for each one. It contains the public key and the signature but how is it structured/encoded. And note that OP_0 pushes an empty element on the stack, not a zero byte! Because I have a Tx with to vins from the same address and I don't see the same public key in the asm field. BIP 141 : The basic Segregated Witness BIP is pretty dense, but youll need to read it. In particular, youll need to write new encode/decode routines for transactions with witnesses (which are made to look like transactions with no inputs, normally invalid). Fortunately, this is fairly easy, and has a flags field for future extensions; see add_tx() . BIP 143 : You need to write a new serializer for your transactions for any signatures youre going to put inside a witness; OP_CHECKSIG works differently! parses and displays data that our industry peers deem unparsable. The BIP is pretty clear, but you can also see tx.c which has a self-contained hash_for_segwit() if you just want SIGHASH_ALL support. During the course of my work at Blockchain Intelligence Group I routinely run different analyses on the Bitcoin blockchain. Fee estimation: presumably the semantics of bitcoins estimatefee RPC call wont change, which means you should create a routi Continue reading Public block explorers do not correctly parse and display all transaction data. G.) takes data integrity seriously, we routinely make sure that even edge-cases are taken care of. In order to minimize errors i frequently compare our data versus that of public blockchain explorers. Some multisig scripts are not decoded properly even by the most used public block explorer. At one point I was looking into multi-signature transactions, and I discovered something interesting. For those who are not familiar with multisig transactions, I will first present a quick multisig summary here. A multisig transaction is one in which the funds are sent to a special multisig address (also called P2SH Pay to Script Hash). The difference between a simple and a multisig address is the number of signatures it takes to redeem an output. With simple addresses (P2PKH Pay To Pub Key Hash), the signature required to redeem an output previously sent to that address is the one of the address itself. Multisig addresses can have a number of signatories required to redeem an output. When creating a multisig address we can specify the number of signatures required (we can look this up in our bitcoin wallet by typing help addmultisigaddress into the console of the debug window). We also specify all the addresses that can sign for outputs sent to this newly created multisig address. So we have n signatures required and m number of addresses eligible to sign, thats why often you see the n out of m phrase associated with multisignature addresses. I have created a vanity address Continue reading All bitcoin transactions have scripts embedded into its inputs and outputs. The scripts use a very simple programming language, which is evaluated from left to right using a stack. The language is designed such that it guarantees all scripts will execute in a limited amount of time (it is not Turing-Complete). When a transaction is validated, the input scripts are concatenated with the output scripts and evaluated. To be valid, all transaction scripts must evaluate to true. A good analogy for how this works is that the output scripts are puzzles that specify in which conditions can those bitcoins be spent. The input scripts provide the correct data to make those output scripts evaluate to true. For more detailed information about the bitcoin scripting language, check the online reference on bitcoin's wiki . The Script object provides an interface to construct, parse, and identify bitcoin scripts. It also gives simple interfaces to create most common script types. This class is useful if you want to create custom input or output scripts. In other case, you should probably use Transaction. Here's how to use Script to create the five most common script types: This is the most commonly used transaction output script. It's used to pay to a bitcoin address (a bitcoin address is a public key hash encoded in base58check) // create a new p2pkh paying to a specific addressvar address = String('1Na TVw XDDUJa XDQajoa9Mq Hhz4u Txtg K14');var script = Script.build Public Key Hash Out(address);assert(String() === 'OP_DUP OP_HASH160 20 0xecae7d092947b7ee4998e254aa48900d26d2ce1d OP_EQUALVERIFY OP_CHECKSIG'); Pay to public key scripts are a simplified form of the p2pkh, but aren't commonly used in new transactions anymore, because p2pkh scripts are more secure (the public ke Continue reading A Bitcoin lives as code inside a computer. Chances are you have never used a Bitcoin, but youve probably heard of it. The virtual currency is popping up more and more in the news and the government has been showing an increased interest in the subject. For instance, the top Democrat and Republican on the Senates Homeland Security and Governmental Affairs Committee this week told federal financial regulators and law enforcement officials to explain how they are keeping tabs on virtual currencies, including the S.2 billion market for Bitcoins. What follows is guide to understanding the currency, why its used and why the government is paying attention. At its most basic level a Bitcoin is a form of money that can be used to pay for products or services just like the dollar bills that sit in your wallet. Its intangible, but it works in many ways like cold, hard cash. To acquire a Bitcoin, you need to buy it with another currency or have someone send it to you in a transaction. To hold a Bitcoin, you need to keep it in a digital wallet, a piece of software, on your local computer or you can you can allow a company to hold your wallet on their servers. Bitcoin payments are made by transferring the digital currency between two users wallets. The fees for these transfers are lower than for more traditional forms of payments, like using a credit card or a bank transfer, because they are not backed by the safeguards and intermediary services provided by companies like Visa or Bank of America.

date: 02-May-2021 11:22next


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