// Written in 2014 by Andrew Poelstra // SPDX-License-Identifier: CC0-1.0 //! Blockdata constants. //! //! This module provides various constants relating to the blockchain and //! consensus code. In particular, it defines the genesis block and its //! single transaction. //! use crate::prelude::*; use core::default::Default; use bitcoin_internals::impl_array_newtype; use crate::hashes::hex::{self, HexIterator}; use crate::hashes::{Hash, sha256d}; use crate::blockdata::script; use crate::blockdata::opcodes::all::*; use crate::blockdata::locktime::absolute; use crate::blockdata::transaction::{OutPoint, Transaction, TxOut, TxIn, Sequence}; use crate::blockdata::block::{Block, BlockHeader, BlockVersion}; use crate::blockdata::witness::Witness; use crate::network::constants::Network; use crate::pow::CompactTarget; use crate::internal_macros::impl_bytes_newtype; /// How many satoshis are in "one bitcoin" pub const COIN_VALUE: u64 = 100_000_000; /// How many seconds between blocks we expect on average pub const TARGET_BLOCK_SPACING: u32 = 600; /// How many blocks between diffchanges pub const DIFFCHANGE_INTERVAL: u32 = 2016; /// How much time on average should occur between diffchanges pub const DIFFCHANGE_TIMESPAN: u32 = 14 * 24 * 3600; /// The maximum allowed weight for a block, see BIP 141 (network rule) pub const MAX_BLOCK_WEIGHT: u32 = 4_000_000; /// The minimum transaction weight for a valid serialized transaction pub const MIN_TRANSACTION_WEIGHT: u32 = 4 * 60; /// The factor that non-witness serialization data is multiplied by during weight calculation pub const WITNESS_SCALE_FACTOR: usize = 4; /// The maximum allowed number of signature check operations in a block pub const MAX_BLOCK_SIGOPS_COST: i64 = 80_000; /// Mainnet (bitcoin) pubkey address prefix. pub const PUBKEY_ADDRESS_PREFIX_MAIN: u8 = 0; // 0x00 /// Mainnet (bitcoin) script address prefix. pub const SCRIPT_ADDRESS_PREFIX_MAIN: u8 = 5; // 0x05 /// Test (tesnet, signet, regtest) pubkey address prefix. pub const PUBKEY_ADDRESS_PREFIX_TEST: u8 = 111; // 0x6f /// Test (tesnet, signet, regtest) script address prefix. pub const SCRIPT_ADDRESS_PREFIX_TEST: u8 = 196; // 0xc4 /// The maximum allowed script size. pub const MAX_SCRIPT_ELEMENT_SIZE: usize = 520; /// How may blocks between halvings. pub const SUBSIDY_HALVING_INTERVAL: u32 = 210_000; /// Maximum allowed value for an integer in Script. pub const MAX_SCRIPTNUM_VALUE: u32 = 0x80000000; // 2^31 /// The maximum value allowed in an output (useful for sanity checking, /// since keeping everything below this value should prevent overflows /// if you are doing anything remotely sane with monetary values). pub fn max_money(_: Network) -> u64 { 21_000_000 * COIN_VALUE } /// Constructs and returns the coinbase (and only) transaction of the Bitcoin genesis block fn bitcoin_genesis_tx() -> Transaction { // Base let mut ret = Transaction { version: 1, lock_time: absolute::PackedLockTime::ZERO, input: vec![], output: vec![], }; // Inputs let in_script = script::Builder::new().push_scriptint(486604799) .push_scriptint(4) .push_slice(b"The Times 03/Jan/2009 Chancellor on brink of second bailout for banks") .into_script(); ret.input.push(TxIn { previous_output: OutPoint::null(), script_sig: in_script, sequence: Sequence::MAX, witness: Witness::default(), }); // Outputs let script_bytes: Result, hex::Error> = HexIterator::new("04678afdb0fe5548271967f1a67130b7105cd6a828e03909a67962e0ea1f61deb649f6bc3f4cef38c4f35504e51ec112de5c384df7ba0b8d578a4c702b6bf11d5f").unwrap() .collect(); let out_script = script::Builder::new() .push_slice(script_bytes.unwrap().as_slice()) .push_opcode(OP_CHECKSIG) .into_script(); ret.output.push(TxOut { value: 50 * COIN_VALUE, script_pubkey: out_script }); // end ret } /// Constructs and returns the genesis block pub fn genesis_block(network: Network) -> Block { let txdata = vec![bitcoin_genesis_tx()]; let hash: sha256d::Hash = txdata[0].txid().into(); let merkle_root = hash.into(); match network { Network::Bitcoin => { Block { header: BlockHeader { version: BlockVersion(1), prev_blockhash: Hash::all_zeros(), merkle_root, time: 1231006505, bits: CompactTarget::from_consensus(0x1d00ffff), nonce: 2083236893 }, txdata, } } Network::Testnet => { Block { header: BlockHeader { version: BlockVersion(1), prev_blockhash: Hash::all_zeros(), merkle_root, time: 1296688602, bits: CompactTarget::from_consensus(0x1d00ffff), nonce: 414098458 }, txdata, } } Network::Signet => { Block { header: BlockHeader { version: BlockVersion(1), prev_blockhash: Hash::all_zeros(), merkle_root, time: 1598918400, bits: CompactTarget::from_consensus(0x1e0377ae), nonce: 52613770 }, txdata, } } Network::Regtest => { Block { header: BlockHeader { version: BlockVersion(1), prev_blockhash: Hash::all_zeros(), merkle_root, time: 1296688602, bits: CompactTarget::from_consensus(0x207fffff), nonce: 2 }, txdata, } } } } /// The uniquely identifying hash of the target blockchain. #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)] pub struct ChainHash([u8; 32]); impl_array_newtype!(ChainHash, u8, 32); impl_bytes_newtype!(ChainHash, 32); impl ChainHash { // Mainnet value can be verified at https://github.com/lightning/bolts/blob/master/00-introduction.md /// `ChainHash` for mainnet bitcoin. pub const BITCOIN: Self = Self([111, 226, 140, 10, 182, 241, 179, 114, 193, 166, 162, 70, 174, 99, 247, 79, 147, 30, 131, 101, 225, 90, 8, 156, 104, 214, 25, 0, 0, 0, 0, 0]); /// `ChainHash` for testnet bitcoin. pub const TESTNET: Self = Self([67, 73, 127, 215, 248, 38, 149, 113, 8, 244, 163, 15, 217, 206, 195, 174, 186, 121, 151, 32, 132, 233, 14, 173, 1, 234, 51, 9, 0, 0, 0, 0]); /// `ChainHash` for signet bitcoin. pub const SIGNET: Self = Self([246, 30, 238, 59, 99, 163, 128, 164, 119, 160, 99, 175, 50, 178, 187, 201, 124, 159, 249, 240, 31, 44, 66, 37, 233, 115, 152, 129, 8, 0, 0, 0]); /// `ChainHash` for regtest bitcoin. pub const REGTEST: Self = Self([6, 34, 110, 70, 17, 26, 11, 89, 202, 175, 18, 96, 67, 235, 91, 191, 40, 195, 79, 58, 94, 51, 42, 31, 199, 178, 183, 60, 241, 136, 145, 15]); /// Returns the hash of the `network` genesis block for use as a chain hash. /// /// See [BOLT 0](https://github.com/lightning/bolts/blob/ffeece3dab1c52efdb9b53ae476539320fa44938/00-introduction.md#chain_hash) /// for specification. pub const fn using_genesis_block(network: Network) -> Self { let hashes = [Self::BITCOIN, Self::TESTNET, Self::SIGNET, Self::REGTEST]; hashes[network as usize] } } #[cfg(test)] mod test { use super::*; use crate::hashes::hex::{ToHex, FromHex}; use crate::network::constants::Network; use crate::consensus::encode::serialize; use crate::blockdata::locktime::absolute; #[test] fn bitcoin_genesis_first_transaction() { let gen = bitcoin_genesis_tx(); assert_eq!(gen.version, 1); assert_eq!(gen.input.len(), 1); assert_eq!(gen.input[0].previous_output.txid, Hash::all_zeros()); assert_eq!(gen.input[0].previous_output.vout, 0xFFFFFFFF); assert_eq!(serialize(&gen.input[0].script_sig), Vec::from_hex("4d04ffff001d0104455468652054696d65732030332f4a616e2f32303039204368616e63656c6c6f72206f6e206272696e6b206f66207365636f6e64206261696c6f757420666f722062616e6b73").unwrap()); assert_eq!(gen.input[0].sequence, Sequence::MAX); assert_eq!(gen.output.len(), 1); assert_eq!(serialize(&gen.output[0].script_pubkey), Vec::from_hex("434104678afdb0fe5548271967f1a67130b7105cd6a828e03909a67962e0ea1f61deb649f6bc3f4cef38c4f35504e51ec112de5c384df7ba0b8d578a4c702b6bf11d5fac").unwrap()); assert_eq!(gen.output[0].value, 50 * COIN_VALUE); assert_eq!(gen.lock_time, absolute::PackedLockTime::ZERO); assert_eq!(gen.wtxid().to_hex(), "4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b"); } #[test] fn bitcoin_genesis_full_block() { let gen = genesis_block(Network::Bitcoin); assert_eq!(gen.header.version, BlockVersion(1)); assert_eq!(gen.header.prev_blockhash, Hash::all_zeros()); assert_eq!(gen.header.merkle_root.to_hex(), "4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b"); assert_eq!(gen.header.time, 1231006505); assert_eq!(gen.header.bits, CompactTarget::from_consensus(0x1d00ffff)); assert_eq!(gen.header.nonce, 2083236893); assert_eq!(gen.header.block_hash().to_hex(), "000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f"); } #[test] fn testnet_genesis_full_block() { let gen = genesis_block(Network::Testnet); assert_eq!(gen.header.version, BlockVersion(1)); assert_eq!(gen.header.prev_blockhash, Hash::all_zeros()); assert_eq!(gen.header.merkle_root.to_hex(), "4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b"); assert_eq!(gen.header.time, 1296688602); assert_eq!(gen.header.bits, CompactTarget::from_consensus(0x1d00ffff)); assert_eq!(gen.header.nonce, 414098458); assert_eq!(gen.header.block_hash().to_hex(), "000000000933ea01ad0ee984209779baaec3ced90fa3f408719526f8d77f4943"); } #[test] fn signet_genesis_full_block() { let gen = genesis_block(Network::Signet); assert_eq!(gen.header.version, BlockVersion(1)); assert_eq!(gen.header.prev_blockhash, Hash::all_zeros()); assert_eq!(gen.header.merkle_root.to_hex(), "4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b"); assert_eq!(gen.header.time, 1598918400); assert_eq!(gen.header.bits, CompactTarget::from_consensus(0x1e0377ae)); assert_eq!(gen.header.nonce, 52613770); assert_eq!(gen.header.block_hash().to_hex(), "00000008819873e925422c1ff0f99f7cc9bbb232af63a077a480a3633bee1ef6"); } // The *_chain_hash tests are sanity/regression tests, they verify that the const byte array // representing the genesis block is the same as that created by hashing the genesis block. fn chain_hash_and_genesis_block(network: Network) { use crate::hashes::sha256; // The genesis block hash is a double-sha256 and it is displayed backwards. let genesis_hash = genesis_block(network).block_hash(); // We abuse the sha256 hash here so we get a LowerHex impl that does not print the hex backwards. let hash = sha256::Hash::from_slice(&genesis_hash.into_inner()).unwrap(); let want = format!("{:02x}", hash); let chain_hash = ChainHash::using_genesis_block(network); let got = format!("{:02x}", chain_hash); // Compare strings because the spec specifically states how the chain hash must encode to hex. assert_eq!(got, want); match network { Network::Bitcoin => {}, Network::Testnet => {}, Network::Signet => {}, Network::Regtest => {}, // Update ChainHash::using_genesis_block and chain_hash_genesis_block with new variants. } } macro_rules! chain_hash_genesis_block { ($($test_name:ident, $network:expr);* $(;)*) => { $( #[test] fn $test_name() { chain_hash_and_genesis_block($network); } )* } } chain_hash_genesis_block! { mainnet_chain_hash_genesis_block, Network::Bitcoin; testnet_chain_hash_genesis_block, Network::Testnet; signet_chain_hash_genesis_block, Network::Signet; regtest_chain_hash_genesis_block, Network::Regtest; } // Test vector taken from: https://github.com/lightning/bolts/blob/master/00-introduction.md #[test] fn mainnet_chain_hash_test_vector() { let got = ChainHash::using_genesis_block(Network::Bitcoin).to_hex(); let want = "6fe28c0ab6f1b372c1a6a246ae63f74f931e8365e15a089c68d6190000000000"; assert_eq!(got, want); } }