hamilton/src/crypto/utils.js

Tools and utilities for interacting with Project Hamilton OpenCBDC atomizer and 2pc environments

const schnorr = require('bip-schnorr');

/**
 * Return sha256 of input b
 * @param {*} b 
 * @returns 
 */
 
const sha256 = function a(b){function c(a,b){return a>>>b|a<<32-b;}for(var d,e,f=Math.pow,g=f(2,32),h='length',i='',j=[],k=8*b[h],l=a.h=a.h||[],m=a.k=a.k||[],n=m[h],o={},p=2;64>n;p++)if(!o[p]){for(d=0;313>d;d+=p)o[d]=p;l[n]=f(p,.5)*g|0,m[n++]=f(p,1/3)*g|0;}for(b+='\x80';b[h]%64-56;)b+='\x00';for(d=0;d<b[h];d++){if(e=b.charCodeAt(d),e>>8)return;j[d>>2]|=e<<(3-d)%4*8;}for(j[j[h]]=k/g|0,j[j[h]]=k,e=0;e<j[h];){var q=j.slice(e,e+=16),r=l;for(l=l.slice(0,8),d=0;64>d;d++){var s=q[d-15],t=q[d-2],u=l[0],v=l[4],w=l[7]+(c(v,6)^c(v,11)^c(v,25))+(v&l[5]^~v&l[6])+m[d]+(q[d]=16>d?q[d]:q[d-16]+(c(s,7)^c(s,18)^s>>>3)+q[d-7]+(c(t,17)^c(t,19)^t>>>10)|0),x=(c(u,2)^c(u,13)^c(u,22))+(u&l[1]^u&l[2]^l[1]&l[2]);l=[w+x|0].concat(l),l[4]=l[4]+w|0;}for(d=0;8>d;d++)l[d]=l[d]+r[d]|0;}for(d=0;8>d;d++)for(e=3;e+1;e--){var y=l[d]>>8*e&255;i+=(16>y?0:'')+y.toString(16);}
    return i;};

/**
 * Returns signature that signed message {message} with privateKey {privateKey}
 * @param {String} secretKey
 * @param {String} message
 * @returns {*} signature  - signature as valid hexadecimal string
 */
const sign = (secretKey, message) => {
    const messageHash = sha256(message);
    return schnorr.sign(secretKey, Buffer.from(messageHash, 'hex')).toString('hex');
};

/**
 * Returns true or false whether the produced signature is validly signed publicKey
 * @param {String} pubkey - publicKey
 * @param {String} message 32 byte string hash
 * @param {String} signature
 * @throws {Error} if signature verification fails
 */
const verify = (publicKey, message, signature) => {
    const pubkeyBuf = Buffer.from(publicKey, 'hex');
    const messageBuf = Buffer.from(message, 'hex');
    const sigBuf = Buffer.from(signature, 'hex');
    try {
        schnorr.verify(pubkeyBuf, messageBuf, sigBuf);
    } catch (error) {
        console.log('Error msg: ', error);  
        return false;
    }
    return true;
};

module.exports = {
    sign,
    sha256,
    verify
};