Time slots app prototype
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import BN from "../bn.js";
import elliptic from "../elliptic";
import parseKeys from "../parse-asn1";
import * as curves from "./curves.json";
var EC = elliptic.ec;
function verify(sig, hash, key, signType, tag) {
var pub = parseKeys(key);
if (pub.type === 'ec') {
// rsa keys can be interpreted as ecdsa ones in openssl
if (signType !== 'ecdsa' && signType !== 'ecdsa/rsa')
throw new Error('wrong public key type');
return ecVerify(sig, hash, pub);
}
else if (pub.type === 'dsa') {
if (signType !== 'dsa')
throw new Error('wrong public key type');
return dsaVerify(sig, hash, pub);
}
else {
if (signType !== 'rsa' && signType !== 'ecdsa/rsa')
throw new Error('wrong public key type');
}
hash = Buffer.concat([tag, hash]);
var len = pub.modulus.byteLength();
var pad = [1];
var padNum = 0;
while (hash.length + pad.length + 2 < len) {
pad.push(0xff);
padNum++;
}
pad.push(0x00);
var i = -1;
while (++i < hash.length) {
pad.push(hash[i]);
}
pad = Buffer.from(pad);
var red = BN.mont(pub.modulus);
sig = new BN(sig).toRed(red);
sig = sig.redPow(new BN(pub.publicExponent));
sig = Buffer.from(sig.fromRed().toArray());
var out = padNum < 8 ? 1 : 0;
len = Math.min(sig.length, pad.length);
if (sig.length !== pad.length)
out = 1;
i = -1;
while (++i < len)
out |= sig[i] ^ pad[i];
return out === 0;
}
function ecVerify(sig, hash, pub) {
var curveId = curves[pub.data.algorithm.curve.join('.')];
if (!curveId)
throw new Error('unknown curve ' + pub.data.algorithm.curve.join('.'));
var curve = new EC(curveId);
var pubkey = pub.data.subjectPrivateKey.data;
return curve.verify(hash, sig, pubkey);
}
function dsaVerify(sig, hash, pub) {
var p = pub.data.p;
var q = pub.data.q;
var g = pub.data.g;
var y = pub.data.pub_key;
var unpacked = parseKeys.signature.decode(sig, 'der');
var s = unpacked.s;
var r = unpacked.r;
checkValue(s, q);
checkValue(r, q);
var montp = BN.mont(p);
var w = s.invm(q);
var v = g.toRed(montp)
.redPow(new BN(hash).mul(w).mod(q))
.fromRed()
.mul(y.toRed(montp).redPow(r.mul(w).mod(q)).fromRed())
.mod(p)
.mod(q);
return v.cmp(r) === 0;
}
function checkValue(b, q) {
if (b.cmpn(0) <= 0)
throw new Error('invalid sig');
if (b.cmp(q) >= q)
throw new Error('invalid sig');
}
export default verify;