crypto-signer/lib/signer.js

crypto-signer is a utility library used to sign transactions in MediSOT v2

"use strict";
/**
 * Signing function for Hyperledger Fabric
 *
 * Example for usage can be found under test directory
 */
Object.defineProperty(exports, "__esModule", { value: true });
exports.CryptoSigner = void 0;
var elliptic = require('elliptic');
var KEYUTIL = require('jsrsasign').KEYUTIL;
var utils_1 = require("./utils");
var CryptoSigner = /** @class */ (function () {
    function CryptoSigner() {
    }
    CryptoSigner.prototype.signECDSAp256 = function (msgHash, privKeyPEM) {
        var prvKeyHex = utils_1.getHexKey(privKeyPEM); // convert the pem encoded key to hex encoded private key
        var EC = elliptic.ec;
        var ecdsaCurve = elliptic.curves['p256'];
        var ecdsa = new EC(ecdsaCurve);
        var signKey = ecdsa.keyFromPrivate(prvKeyHex, 'hex');
        var sig = ecdsa.sign(Buffer.from(msgHash, 'hex'), signKey);
        sig = this._preventECDSAp256Malleability(sig);
        // now we have the signature, next we should send the signed transaction proposal to the peer
        var signature = Buffer.from(sig.toDER());
        return signature;
    };
    CryptoSigner.prototype.verifyECDSAp256 = function (msgHash, signature, pubKeyPEM) {
        var pubKey = KEYUTIL.getKey(utils_1.cleanUpPEM(pubKeyPEM));
        var pubPoint = pubKey.getPublicKeyXYHex();
        var EC = elliptic.ec;
        var ecdsaCurve = elliptic.curves['p256'];
        var ecdsa = new EC(ecdsaCurve);
        return ecdsa.verify(msgHash, signature, pubPoint);
    };
    CryptoSigner.prototype._preventECDSAp256Malleability = function (sig) {
        var halfOrder = elliptic.curves.p256.n.shrn(1);
        // in order to guarantee 's' falls in the lower range of the order, as explained in the above link,
        // first see if 's' is larger than half of the order, if so, it needs to be specially treated
        if (sig.s.cmp(halfOrder) === 1) { // module 'bn.js', file lib/bn.js, method cmp()
            // convert from BigInteger used by jsrsasign Key objects and bn.js used by elliptic Signature objects
            var bigNum = elliptic.curves.p256.n;
            sig.s = bigNum.sub(sig.s);
        }
        return sig;
    };
    return CryptoSigner;
}());
exports.CryptoSigner = CryptoSigner;