evmprecompiles

Documentation

Overview

Package evmprecompiles implements the Ethereum VM precompile contracts.

This package collects all the precompile functions into a single location for easier integration. The main functionality is implemented elsewhere. This package right now implements:

1. ECRECOVER ✅ -- function ECRecover
2. SHA256 ❌ -- in progress
3. RIPEMD160 ❌ -- postponed
4. ID ❌ -- trivial to implement without function
5. EXPMOD ✅ -- function Expmod
6. BN_ADD ✅ -- function ECAdd
7. BN_MUL ✅ -- function ECMul
8. SNARKV ✅ -- function ECPair
9. BLAKE2F ❌ -- postponed

This package uses local representation for the arguments. It is up to the user to instantiate corresponding types from their application-specific data.

Index

• func ECAdd(api frontend.API, P, Q *sw_emulated.AffinePoint[emulated.BN254Fp]) *sw_emulated.AffinePoint[emulated.BN254Fp]
• func ECMul(api frontend.API, P *sw_emulated.AffinePoint[emulated.BN254Fp], ...) *sw_emulated.AffinePoint[emulated.BN254Fp]
• func ECPair(api frontend.API, P []*sw_bn254.G1Affine, Q []*sw_bn254.G2Affine)
• func ECRecover(api frontend.API, msg emulated.Element[emulated.Secp256k1Fr], ...) *sw_emulated.AffinePoint[emulated.Secp256k1Fp]
• func Expmod(api frontend.API, base, exp, modulus *emulated.Element[emparams.Mod1e4096]) *emulated.Element[emparams.Mod1e4096]
• func GetHints() []solver.Hint

Functions

func ECAdd

func ECAdd(api frontend.API, P, Q *sw_emulated.AffinePoint[emulated.BN254Fp]) *sw_emulated.AffinePoint[emulated.BN254Fp]

ECAdd implements ALT_BN128_ADD precompile contract at address 0x06.

func ECMul

func ECMul(api frontend.API, P *sw_emulated.AffinePoint[emulated.BN254Fp], u *emulated.Element[emulated.BN254Fr]) *sw_emulated.AffinePoint[emulated.BN254Fp]

ECMul implements ALT_BN128_MUL precompile contract at address 0x07.

func ECPair

func ECPair(api frontend.API, P []*sw_bn254.G1Affine, Q []*sw_bn254.G2Affine)

func ECRecover

func ECRecover(api frontend.API, msg emulated.Element[emulated.Secp256k1Fr],
	v frontend.Variable, r, s emulated.Element[emulated.Secp256k1Fr],
	strictRange frontend.Variable, isFailure frontend.Variable) *sw_emulated.AffinePoint[emulated.Secp256k1Fp]

ECRecover implements ECRECOVER precompile contract at address 0x01.

The method allows checking both the transaction signatures and ECRecover precompile calls. The difference between TX signature verification and ECRecover precompile call is that there is additional check for s <= (Fr-1)/2 in the former case. To enforce this check, the strictRange variable should be set to 1.

The isFailure variable is set to 1 when the inputs are expected to be invalid in the context of ECRecover. The failure cases are:

1. The public key is zero.
2. The value r^3 + 7 is not a quadratic residue.

func Expmod

func Expmod(api frontend.API, base, exp, modulus *emulated.Element[emparams.Mod1e4096]) *emulated.Element[emparams.Mod1e4096]

Expmod implements MODEXP precompile contract at address 0x05.

Internally, uses 4k elements for representing the base, exponent and modulus, upper bounding the sizes of the inputs. The runtime is constant regardless of the actual length of the inputs.

func GetHints

func GetHints() []solver.Hint

GetHints returns all the hints used in this package.