revm_precompile/
secp256k1.rs

1//! `ecrecover` precompile.
2//!
3//! Depending on enabled features, it will use different implementations of `ecrecover`.
4//! * [`k256`](https://crates.io/crates/k256) - uses maintained pure rust lib `k256`, it is perfect use for no_std environments.
5//! * [`secp256k1`](https://crates.io/crates/secp256k1) - uses `bitcoin_secp256k1` lib, it is a C implementation of secp256k1 used in bitcoin core.
6//!   It is faster than k256 and enabled by default and in std environment.
7
8//!   Order of preference is `secp256k1` -> `k256`. Where if no features are enabled, it will use `k256`.
9//!
10//! Input format:
11//! [32 bytes for message][64 bytes for signature][1 byte for recovery id]
12//!
13//! Output format:
14//! [32 bytes for recovered address]
15#[cfg(feature = "secp256k1")]
16pub mod bitcoin_secp256k1;
17pub mod k256;
18
19use crate::{
20    crypto, utilities::right_pad, Precompile, PrecompileError, PrecompileId, PrecompileOutput,
21    PrecompileResult,
22};
23use primitives::{alloy_primitives::B512, Bytes, B256};
24
25/// `ecrecover` precompile, containing address and function to run.
26pub const ECRECOVER: Precompile = Precompile::new(
27    PrecompileId::EcRec,
28    crate::u64_to_address(1),
29    ec_recover_run,
30);
31
32/// `ecrecover` precompile function. Read more about input and output format in [this module docs](self).
33pub fn ec_recover_run(input: &[u8], gas_limit: u64) -> PrecompileResult {
34    const ECRECOVER_BASE: u64 = 3_000;
35
36    if ECRECOVER_BASE > gas_limit {
37        return Err(PrecompileError::OutOfGas);
38    }
39
40    let input = right_pad::<128>(input);
41
42    // `v` must be a 32-byte big-endian integer equal to 27 or 28.
43    if !(input[32..63].iter().all(|&b| b == 0) && matches!(input[63], 27 | 28)) {
44        return Ok(PrecompileOutput::new(ECRECOVER_BASE, Bytes::new()));
45    }
46
47    let msg = <&B256>::try_from(&input[0..32]).unwrap();
48    let recid = input[63] - 27;
49    let sig = <&B512>::try_from(&input[64..128]).unwrap();
50
51    let res = crypto().secp256k1_ecrecover(&sig.0, recid, &msg.0).ok();
52    let out = res.map(|o| o.to_vec().into()).unwrap_or_default();
53    Ok(PrecompileOutput::new(ECRECOVER_BASE, out))
54}
55
56pub(crate) fn ecrecover_bytes(sig: [u8; 64], recid: u8, msg: [u8; 32]) -> Option<[u8; 32]> {
57    let sig = B512::from_slice(&sig);
58    let msg = B256::from_slice(&msg);
59
60    match ecrecover(&sig, recid, &msg) {
61        Ok(address) => Some(address.0),
62        Err(_) => None,
63    }
64}
65
66// Select the correct implementation based on the enabled features.
67cfg_if::cfg_if! {
68    if #[cfg(feature = "secp256k1")] {
69        pub use bitcoin_secp256k1::ecrecover;
70    } else {
71        pub use k256::ecrecover;
72    }
73}
revm_precompile/secp256k1.rs

revm_precompile/
secp256k1.rs
