ecrecover script node javascript web3 ethereumjs-util

ecrecover.js

#!/usr/bin/env node

/*

Test (1) r/s/v:

> node ecrecover.js \
    0xb9cbc613e7154b248b1fb1cfd190e173c6d4e8e7bd89b754debe1322f9a4a15c \
    0xa58c6ba0acb8005d0e3510396951a7949707428d7db97be8dc114af58a06140f \
    0x0fe3e42fed1daabef16b2a9f3da5d36538898c8a9f491b48b4cef9ee731ff2f3 \
    27

0xe0b28ae70d6f90a64761fdd148c8193a3f80b13f
0xa56a4cd3bbca1866317b0d51ccd64184b62777c4 (median.recover)


Test (2) sig:

> node ecrecover.js \
    0xbfd7990b842673512f0f61acc04c5db7a9c24d474b40baf78566f052a9cd6c74 \
    0xa58c6ba0acb8005d0e3510396951a7949707428d7db97be8dc114af58a06140f0fe3e42fed1daabef16b2a9f3da5d36538898c8a9f491b48b4cef9ee731ff2f31b

0xe0b28ae70d6f90a64761fdd148c8193a3f80b13f
0xa56a4cd3bbca1866317b0d51ccd64184b62777c4 (median.recover)

*/

const Web3 = require('web3');
const web3 = new Web3();
const util = require('ethereumjs-util')
const prefix = new Buffer.from("\x19Ethereum Signed Message:\n32");

function ecrecover(args) {
    // console.log(args);
    var data = Buffer.from(args[0].replace('0x',''), 'hex');
    var r = Buffer.from(args[1].replace('0x',''), 'hex');
    var s = Buffer.from(args[2].replace('0x',''), 'hex');
    var v = parseInt(args[3]);
    // console.log(data,r,s,v);

    var pk = util.ecrecover(data, v, r, s);
    var addr = util.bufferToHex(util.pubToAddress(pk));
    console.log(addr);

    pk = util.ecrecover(util.keccak256(Buffer.concat([prefix, data])), v, r, s);
    addr = util.bufferToHex(util.pubToAddress(pk));
    console.log(addr + ' (median.recover)');
}

function ecrecoverSig(args) {
    var data = Buffer.from(args[0].replace('0x',''), 'hex')
    var sig = Buffer.from(args[1].replace('0x',''), 'hex')
    const res = util.fromRpcSig(sig);
    var pub = util.ecrecover(data, res.v, res.r, res.s);
    var addr = util.bufferToHex(util.pubToAddress(pub));
    console.log(addr);

    pk = util.ecrecover(util.keccak256(Buffer.concat([prefix, data])), res.v, res.r, res.s);
    addr = util.bufferToHex(util.pubToAddress(pk));
    console.log(addr + ' (median.recover)');
}

const args = process.argv.slice(2);
if (args.length != 4) {
    if (args.length == 2) {
        ecrecoverSig(args);
        return;
    }
    console.log('Usage: node ecrecover.js $data $r $s $v');
    console.log(' (or): node ecrecover.js $data $sig\n');
    console.log(' E.g.:  node ecrecover.js 0xabc123 0xdeadbeef 0xbeefdead 28');
} else {
    ecrecover(args);
}