signatureToCompactSignature

Name: viem-go
Author: viem-go

Converts a Signature to a CompactSignature (EIP-2098)

signatureToCompactSignature

Converts a regular Signature to a CompactSignature (EIP-2098) format.

Import

import "github.com/ChefBingbong/viem-go/utils/signature"

Usage

import "github.com/ChefBingbong/viem-go/utils/signature"

sig := &signature.Signature{
  R:       "0x68a020a209d3d56c46f38cc50a33f704f4a9a10a59377f8dd762ac66910e9b90",
  S:       "0x7e865ad05c4035ab5792787d4a0297a43617ae897930a6fe4d822b8faea52064",
  YParity: 0,
}

compact, err := signature.SignatureToCompactSignature(sig)
if err != nil {
  log.Fatal(err)
}

fmt.Printf("R: %s
", compact.R)
// R: 0x68a020a209d3d56c46f38cc50a33f704f4a9a10a59377f8dd762ac66910e9b90

fmt.Printf("YParityAndS: %s
", compact.YParityAndS)
// YParityAndS: 0x7e865ad05c4035ab5792787d4a0297a43617ae897930a6fe4d822b8faea52064

Returns

Type: (*signature.CompactSignature, error)

A compact signature with R and YParityAndS components.

Parameters

signature (required)

Type: *signature.Signature

The signature struct containing R, S, V, and YParity components.

sig := &signature.Signature{
  R:       "0x68a020a209d3d56c46f38cc50a33f704f4a9a10a59377f8dd762ac66910e9b90",
  S:       "0x7e865ad05c4035ab5792787d4a0297a43617ae897930a6fe4d822b8faea52064",
  YParity: 0,
}

compact, _ := signature.SignatureToCompactSignature(sig)

Implementation

This function:

Extracts yParity from either the YParity field or derives it from V
Encodes yParity in the top bit (bit 7) of the first byte of S
Returns a CompactSignature with R and YParityAndS

Notes

The yParity is encoded in the top bit of the first byte of S
If yParity is 1, bit 7 of the first byte is set
If yParity is 0, bit 7 of the first byte is clear
This reduces the signature size from 65 bytes to 64 bytes