signP256 Cheat

crates/cheatcodes/Cargo.toml

@@ -37,3 +37,4 @@ serde_json.workspace = true
 base64.workspace = true
 tracing.workspace = true
 walkdir = "2"
+p256 = "0.13.2"

crates/cheatcodes/spec/src/vm.rs

@@ -239,10 +239,14 @@ interface Vm {
     #[cheatcode(group = Evm, safety = Unsafe)]
     function loadAllocs(string calldata pathToAllocsJson) external;
 
-    /// Signs data.
+    /// Signs `digest` with `privateKey` using the secp2562k1 curve.
     #[cheatcode(group = Evm, safety = Safe)]
     function sign(uint256 privateKey, bytes32 digest) external pure returns (uint8 v, bytes32 r, bytes32 s);
 
+    /// Signs `digest` with `privateKey` using the secp2562r1 curve.
+    #[cheatcode(group = Evm, safety = Safe)]
+    function signP256(uint256 privateKey, bytes32 digest) external pure returns (bytes32 r, bytes32 s);
+
     // -------- Record Storage --------
 
     /// Records all storage reads and writes.

crates/cheatcodes/src/evm.rs

@@ -93,6 +93,13 @@ impl Cheatcode for sign_0Call {
     }
 }
 
+impl Cheatcode for signP256Call {
+    fn apply_full<DB: DatabaseExt>(&self, ccx: &mut CheatsCtxt<DB>) -> Result {
+        let Self { privateKey, digest } = self;
+        super::utils::sign_p256(privateKey, digest, ccx.state)
+    }
+}
+
 impl Cheatcode for recordCall {
     fn apply(&self, state: &mut Cheatcodes) -> Result {
         let Self {} = self;

crates/cheatcodes/src/utils.rs

@@ -17,6 +17,7 @@ use ethers_signers::{
 };
 use foundry_common::types::{ToAlloy, ToEthers};
 use foundry_evm_core::constants::DEFAULT_CREATE2_DEPLOYER;
+use p256::ecdsa::{signature::hazmat::PrehashSigner, Signature, SigningKey as P256SigningKey};
 
 /// The BIP32 default derivation path prefix.
 const DEFAULT_DERIVATION_PATH_PREFIX: &str = "m/44'/60'/0'/0/";
@@ -171,6 +172,22 @@ pub(super) fn sign(private_key: &U256, digest: &B256, chain_id: u64) -> Result {
     Ok((sig.v, r_bytes, s_bytes).abi_encode())
 }
 
+pub(super) fn sign_p256(private_key: &U256, digest: &B256, _state: &mut Cheatcodes) -> Result {
+    ensure!(*private_key != U256::ZERO, "private key cannot be 0");
+    let n = U256::from_limbs(*p256::NistP256::ORDER.as_words());
+    ensure!(
+        *private_key < n,
+        format!("private key must be less than the secp256r1 curve order ({})", n),
+    );
+    let bytes = private_key.to_be_bytes();
+    let signing_key = P256SigningKey::from_bytes((&bytes).into())?;
+    let signature: Signature = signing_key.sign_prehash(digest.as_slice())?;
+    let r_bytes: [u8; 32] = signature.r().to_bytes().into();
+    let s_bytes: [u8; 32] = signature.s().to_bytes().into();
+
+    Ok((r_bytes, s_bytes).abi_encode())
+}
+
 pub(super) fn parse_private_key(private_key: &U256) -> Result<SigningKey> {
     ensure!(*private_key != U256::ZERO, "private key cannot be 0");
     ensure!(
@@ -219,3 +236,66 @@ fn derive_key<W: Wordlist>(mnemonic: &str, path: &str, index: u32) -> Result {
     let private_key = U256::from_be_bytes(wallet.signer().to_bytes().into());
     Ok(private_key.abi_encode())
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::CheatsConfig;
+    use alloy_primitives::FixedBytes;
+    use hex::FromHex;
+    use p256::ecdsa::{signature::hazmat::PrehashVerifier, Signature};
+    use std::{path::PathBuf, sync::Arc};
+
+    fn cheats() -> Cheatcodes {
+        let config = CheatsConfig {
+            ffi: true,
+            root: PathBuf::from(&env!("CARGO_MANIFEST_DIR")),
+            ..Default::default()
+        };
+        Cheatcodes { config: Arc::new(config), ..Default::default() }
+    }
+
+    #[test]
+    fn test_sign_p256() {
+        use p256::ecdsa::VerifyingKey;
+
+        let pk_u256: U256 = "1".parse().unwrap();
+        let signing_key = P256SigningKey::from_bytes(&pk_u256.to_be_bytes().into()).unwrap();
+        let digest = FixedBytes::from_hex(
+            "0x44acf6b7e36c1342c2c5897204fe09504e1e2efb1a900377dbc4e7a6a133ec56",
+        )
+        .unwrap();
+        let mut cheats = cheats();
+
+        let result = sign_p256(&pk_u256, &digest, &mut cheats).unwrap();
+        let result_bytes: [u8; 64] = result.try_into().unwrap();
+        let signature = Signature::from_bytes(&result_bytes.into()).unwrap();
+        let verifying_key = VerifyingKey::from(&signing_key);
+        assert!(verifying_key.verify_prehash(digest.as_slice(), &signature).is_ok());
+    }
+
+    #[test]
+    fn test_sign_p256_pk_too_large() {
+        // max n from https://neuromancer.sk/std/secg/secp256r1
+        let pk =
+            "0xffffffff00000000ffffffffffffffffbce6faada7179e84f3b9cac2fc632551".parse().unwrap();
+        let digest = FixedBytes::from_hex(
+            "0x54705ba3baafdbdfba8c5f9a70f7a89bee98d906b53e31074da7baecdc0da9ad",
+        )
+        .unwrap();
+        let mut cheats = cheats();
+        let result = sign_p256(&pk, &digest, &mut cheats);
+        assert_eq!(result.err().unwrap().to_string(), "private key must be less than the secp256r1 curve order (115792089210356248762697446949407573529996955224135760342422259061068512044369)");
+    }
+
+    #[test]
+    fn test_sign_p256_pk_0() {
+        let digest = FixedBytes::from_hex(
+            "0x54705ba3baafdbdfba8c5f9a70f7a89bee98d906b53e31074da7baecdc0da9ad",
+        )
+        .unwrap();
+        let mut cheats = cheats();
+        let result = sign_p256(&U256::ZERO, &digest, &mut cheats);
+        assert_eq!(result.err().unwrap().to_string(), "private key cannot be 0");
+    }
+}

testdata/cheats/SignP256.t.sol

@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: MIT OR Apache-2.0
+pragma solidity 0.8.18;
+
+import "ds-test/test.sol";
+import "./Vm.sol";
+
+contract SignTest is DSTest {
+    Vm constant vm = Vm(HEVM_ADDRESS);
+
+    function testSignP256() public {
+        bytes32 pk = hex"A8568B74282DCC66FF70F10B4CE5CC7B391282F5381BBB4F4D8DD96974B16E6B";
+        bytes32 digest = hex"54705ba3baafdbdfba8c5f9a70f7a89bee98d906b53e31074da7baecdc0da9ad";
+
+        (bytes32 r, bytes32 s) = vm.signP256(uint256(pk), digest);
+        assertEq(r, hex"7C11C3641B19E7822DB644CBF76ED0420A013928C2FD3E36D8EF983B103BDFE1");
+        assertEq(s, hex"317D89879868D484810D4E508A96109F8C87617B7BE9337411348D7B786F945F");
+    }
+}