// Rust Bitcoin Library // Written in 2014 by // Andrew Poelstra // // To the extent possible under law, the author(s) have dedicated all // copyright and related and neighboring rights to this software to // the public domain worldwide. This software is distributed without // any warranty. // // You should have received a copy of the CC0 Public Domain Dedication // along with this software. // If not, see . // //! Consensus parameters //! //! This module provides predefined set of parameters for different chains. //! use network::constants::Network; use util::uint::Uint256; /// Lowest possible difficulty for Mainnet. See comment on Params::pow_limit for more info. const MAX_BITS_BITCOIN: Uint256 = Uint256([ 0x0000000000000000u64, 0x0000000000000000u64, 0x0000000000000000u64, 0x00000000ffff0000u64, ]); /// Lowest possible difficulty for Testnet. See comment on Params::pow_limit for more info. const MAX_BITS_TESTNET: Uint256 = Uint256([ 0x0000000000000000u64, 0x0000000000000000u64, 0x0000000000000000u64, 0x00000000ffff0000u64, ]); /// Lowest possible difficulty for Signet. See comment on Params::pow_limit for more info. const MAX_BITS_SIGNET: Uint256 = Uint256([ 0x0000000000000000u64, 0x0000000000000000u64, 0x0000000000000000u64, 0x00000377ae000000u64, ]); /// Lowest possible difficulty for Regtest. See comment on Params::pow_limit for more info. const MAX_BITS_REGTEST: Uint256 = Uint256([ 0x0000000000000000u64, 0x0000000000000000u64, 0x0000000000000000u64, 0x7fffff0000000000u64, ]); #[derive(Debug, Clone)] /// Parameters that influence chain consensus. pub struct Params { /// Network for which parameters are valid. pub network: Network, /// Time when BIP16 becomes active. pub bip16_time: u32, /// Block height at which BIP34 becomes active. pub bip34_height: u32, /// Block height at which BIP65 becomes active. pub bip65_height: u32, /// Block height at which BIP66 becomes active. pub bip66_height: u32, /// Minimum blocks including miner confirmation of the total of 2016 blocks in a retargeting period, /// (nPowTargetTimespan / nPowTargetSpacing) which is also used for BIP9 deployments. /// Examples: 1916 for 95%, 1512 for testchains. pub rule_change_activation_threshold: u32, /// Number of blocks with the same set of rules. pub miner_confirmation_window: u32, /// Proof of work limit value. It contains the lowest possible difficulty. /// /// Note that this value differs from Bitcoin Core's powLimit field in that this value is /// attainable, but Bitcoin Core's is not. Specifically, because targets in Bitcoin are always /// rounded to the nearest float expressible in "compact form", not all targets are attainable. /// Still, this should not affect consensus as the only place where the non-compact form of /// this is used in Bitcoin Core's consensus algorithm is in comparison and there are no /// compact-expressible values between Bitcoin Core's and the limit expressed here. pub pow_limit: Uint256, /// Expected amount of time to mine one block. pub pow_target_spacing: u64, /// Difficulty recalculation interval. pub pow_target_timespan: u64, /// Determines whether minimal difficulty may be used for blocks or not. pub allow_min_difficulty_blocks: bool, /// Determines whether retargeting is disabled for this network or not. pub no_pow_retargeting: bool, } impl Params { /// Creates parameters set for the given network. pub fn new(network: Network) -> Self { match network { Network::Bitcoin => Params { network: Network::Bitcoin, bip16_time: 1333238400, // Apr 1 2012 bip34_height: 227931, // 000000000000024b89b42a942fe0d9fea3bb44ab7bd1b19115dd6a759c0808b8 bip65_height: 388381, // 000000000000000004c2b624ed5d7756c508d90fd0da2c7c679febfa6c4735f0 bip66_height: 363725, // 00000000000000000379eaa19dce8c9b722d46ae6a57c2f1a988119488b50931 rule_change_activation_threshold: 1916, // 95% miner_confirmation_window: 2016, pow_limit: MAX_BITS_BITCOIN, pow_target_spacing: 10 * 60, // 10 minutes. pow_target_timespan: 14 * 24 * 60 * 60, // 2 weeks. allow_min_difficulty_blocks: false, no_pow_retargeting: false, }, Network::Testnet => Params { network: Network::Testnet, bip16_time: 1333238400, // Apr 1 2012 bip34_height: 21111, // 0000000023b3a96d3484e5abb3755c413e7d41500f8e2a5c3f0dd01299cd8ef8 bip65_height: 581885, // 00000000007f6655f22f98e72ed80d8b06dc761d5da09df0fa1dc4be4f861eb6 bip66_height: 330776, // 000000002104c8c45e99a8853285a3b592602a3ccde2b832481da85e9e4ba182 rule_change_activation_threshold: 1512, // 75% miner_confirmation_window: 2016, pow_limit: MAX_BITS_TESTNET, pow_target_spacing: 10 * 60, // 10 minutes. pow_target_timespan: 14 * 24 * 60 * 60, // 2 weeks. allow_min_difficulty_blocks: true, no_pow_retargeting: false, }, Network::Signet => Params { network: Network::Signet, bip16_time: 1333238400, // Apr 1 2012 bip34_height: 1, bip65_height: 1, bip66_height: 1, rule_change_activation_threshold: 1916, // 95% miner_confirmation_window: 2016, pow_limit: MAX_BITS_SIGNET, pow_target_spacing: 10 * 60, // 10 minutes. pow_target_timespan: 14 * 24 * 60 * 60, // 2 weeks. allow_min_difficulty_blocks: false, no_pow_retargeting: false, }, Network::Regtest => Params { network: Network::Regtest, bip16_time: 1333238400, // Apr 1 2012 bip34_height: 100000000, // not activated on regtest bip65_height: 1351, bip66_height: 1251, // used only in rpc tests rule_change_activation_threshold: 108, // 75% miner_confirmation_window: 144, pow_limit: MAX_BITS_REGTEST, pow_target_spacing: 10 * 60, // 10 minutes. pow_target_timespan: 14 * 24 * 60 * 60, // 2 weeks. allow_min_difficulty_blocks: true, no_pow_retargeting: true, }, } } /// Calculates the number of blocks between difficulty adjustments. pub fn difficulty_adjustment_interval(&self) -> u64 { self.pow_target_timespan / self.pow_target_spacing } }