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Implement P256 verification via RIP-7212 precompile with Solidity fallback (#4881)

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Co-authored-by: Ernesto García <ernestognw@gmail.com>
Co-authored-by: cairo <cairoeth@protonmail.com>
Co-authored-by: sudo rm -rf --no-preserve-root / <pcaversaccio@users.noreply.github.com>
This commit is contained in:
Hadrien Croubois
2024-07-03 09:17:46 +02:00
committed by GitHub
parent ccc110360f
commit 05f218fb66
11 changed files with 4400 additions and 5 deletions
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19
contracts/utils/math/Math.sol
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@ -237,8 +237,8 @@ library Math {
*
* If the input value is not inversible, 0 is returned.
*
* NOTE: If you know for sure that n is (big) a prime, it may be cheaper to use Ferma's little theorem and get the
* inverse using `Math.modExp(a, n - 2, n)`.
* NOTE: If you know for sure that n is (big) a prime, it may be cheaper to use Fermat's little theorem and get the
* inverse using `Math.modExp(a, n - 2, n)`. See {invModPrime}.
*/
function invMod(uint256 a, uint256 n) internal pure returns (uint256) {
unchecked {
@ -288,6 +288,21 @@ library Math {
}
}
/**
* @dev Variant of {invMod}. More efficient, but only works if `p` is known to be a prime greater than `2`.
*
* From https://en.wikipedia.org/wiki/Fermat%27s_little_theorem[Fermat's little theorem], we know that if p is
* prime, then `a**(p-1) ≡ 1 mod p`. As a consequence, we have `a * a**(p-2) ≡ 1 mod p`, which means that
* `a**(p-2)` is the modular multiplicative inverse of a in Fp.
*
* NOTE: this function does NOT check that `p` is a prime greater than `2`.
*/
function invModPrime(uint256 a, uint256 p) internal view returns (uint256) {
unchecked {
return Math.modExp(a, p - 2, p);
}
}
/**
* @dev Returns the modular exponentiation of the specified base, exponent and modulus (b ** e % m)
*