Andrew Poelstra 2664f978f3 Merge rust-bitcoin/rust-bitcoin#2213: Fix InputWeightPrediction::P2WPKH_MAX constant DER sig length ... f41ebc2149 Add test for input weight predictions (conduition) 4514a80a23 Fix the InputWeightPrediction constants for DER signatures (conduition) b5ce219c62 add weight method to InputWeightPrediction (conduition) Pull request description: The `P2WPKH_MAX` constant assumed DER signatures in the witness have a max length of 73. In practice, their maximum length is 72, because [BIP62](https://github.com/bitcoin/bips/blob/master/bip-0062.mediawiki) forbids nodes from relaying transactions which contain non-canonical ECDSA signatures (i.e. TX sigs must have an $s$ value of less than $\frac{n}{2}$). This means $s$ is never encoded with a leading zero byte, and the signature as a whole never exceeds 72 bytes in total encoded length. The `ground_p2wpkh` function was already correct; only the constant needed to be corrected. Technically 73 bytes *is* the upper limit for signatures, as nothing forbids miners from including such non-standard transaction signatures in blocks, but for the purposes of fee estimation and input weight prediction, 72 is the number which 99.9% of implementations should use as their ceiling. We already use it as the ceiling for the `ground_p2wpkh` function - `ground_p2wpkh(0)` returns a prediction which uses a witness signature of length 72. Reference: - https://bitcoin.stackexchange.com/questions/77191/what-is-the-maximum-size-of-a-der-encoded-ecdsa-signature - https://bitcoin.stackexchange.com/questions/106435/are-high-s-ecdsa-signatures-forbidden-in-segwit-witnesses - https://github.com/bitcoin/bips/blob/master/bip-0062.mediawiki To enable testing, I added a `weight()` method to `InputWeightPrediction` and made it public but i'm not sure whether it has a use-case. Let me know if I should make it private instead. ACKs for top commit: tcharding: ACK f41ebc2149 apoelstra: ACK f41ebc2149 Tree-SHA512: 10e837bad9881c0efebb0598eaefd4ab039f2a6ececead75a68e253d84f5e85cb30496a6069eee8dfe9714773f3aa23cfe373f5d88d1c5609e1b1be1ff142e37		2023-11-22 20:36:11 +00:00
..
contrib	hashes: Bump version to 0.13.0	2023-08-24 12:25:42 +10:00
embedded	Add a `bitcoin_io` crate	2023-11-07 05:50:42 +00:00
examples	Use Message::from_digest	2023-10-11 08:16:25 +11:00
src	Merge rust-bitcoin/rust-bitcoin#2213: Fix InputWeightPrediction::P2WPKH_MAX constant DER sig length	2023-11-22 20:36:11 +00:00
tests	Replace hex_script macro with a helper function	2023-10-20 10:20:23 +02:00
CHANGELOG.md	Add a missing link to #2006 in 'bitcoin/CHANGELOG.md'	2023-10-26 21:06:48 +02:00
Cargo.toml	bitcoin:: Remove dev dependency serde_derive	2023-11-20 15:17:30 +11:00
build.rs	Create uniform build script	2023-10-30 14:40:41 +01:00