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- // much of this based on https://github.com/indutny/self-signed/blob/gh-pages/lib/rsa.js
- var Buffer = require('safe-buffer').Buffer
- var createHmac = require('create-hmac')
- var crt = require('browserify-rsa')
- var EC = require('elliptic').ec
- var BN = require('bn.js')
- var parseKeys = require('parse-asn1')
- var curves = require('./curves.json')
- function sign (hash, key, hashType, signType, tag) {
- var priv = parseKeys(key)
- if (priv.curve) {
- // rsa keys can be interpreted as ecdsa ones in openssl
- if (signType !== 'ecdsa' && signType !== 'ecdsa/rsa') throw new Error('wrong private key type')
- return ecSign(hash, priv)
- } else if (priv.type === 'dsa') {
- if (signType !== 'dsa') throw new Error('wrong private key type')
- return dsaSign(hash, priv, hashType)
- } else {
- if (signType !== 'rsa' && signType !== 'ecdsa/rsa') throw new Error('wrong private key type')
- }
- hash = Buffer.concat([tag, hash])
- var len = priv.modulus.byteLength()
- var pad = [0, 1]
- while (hash.length + pad.length + 1 < len) pad.push(0xff)
- pad.push(0x00)
- var i = -1
- while (++i < hash.length) pad.push(hash[i])
- var out = crt(pad, priv)
- return out
- }
- function ecSign (hash, priv) {
- var curveId = curves[priv.curve.join('.')]
- if (!curveId) throw new Error('unknown curve ' + priv.curve.join('.'))
- var curve = new EC(curveId)
- var key = curve.keyFromPrivate(priv.privateKey)
- var out = key.sign(hash)
- return Buffer.from(out.toDER())
- }
- function dsaSign (hash, priv, algo) {
- var x = priv.params.priv_key
- var p = priv.params.p
- var q = priv.params.q
- var g = priv.params.g
- var r = new BN(0)
- var k
- var H = bits2int(hash, q).mod(q)
- var s = false
- var kv = getKey(x, q, hash, algo)
- while (s === false) {
- k = makeKey(q, kv, algo)
- r = makeR(g, k, p, q)
- s = k.invm(q).imul(H.add(x.mul(r))).mod(q)
- if (s.cmpn(0) === 0) {
- s = false
- r = new BN(0)
- }
- }
- return toDER(r, s)
- }
- function toDER (r, s) {
- r = r.toArray()
- s = s.toArray()
- // Pad values
- if (r[0] & 0x80) r = [0].concat(r)
- if (s[0] & 0x80) s = [0].concat(s)
- var total = r.length + s.length + 4
- var res = [0x30, total, 0x02, r.length]
- res = res.concat(r, [0x02, s.length], s)
- return Buffer.from(res)
- }
- function getKey (x, q, hash, algo) {
- x = Buffer.from(x.toArray())
- if (x.length < q.byteLength()) {
- var zeros = Buffer.alloc(q.byteLength() - x.length)
- x = Buffer.concat([zeros, x])
- }
- var hlen = hash.length
- var hbits = bits2octets(hash, q)
- var v = Buffer.alloc(hlen)
- v.fill(1)
- var k = Buffer.alloc(hlen)
- k = createHmac(algo, k).update(v).update(Buffer.from([0])).update(x).update(hbits).digest()
- v = createHmac(algo, k).update(v).digest()
- k = createHmac(algo, k).update(v).update(Buffer.from([1])).update(x).update(hbits).digest()
- v = createHmac(algo, k).update(v).digest()
- return { k: k, v: v }
- }
- function bits2int (obits, q) {
- var bits = new BN(obits)
- var shift = (obits.length << 3) - q.bitLength()
- if (shift > 0) bits.ishrn(shift)
- return bits
- }
- function bits2octets (bits, q) {
- bits = bits2int(bits, q)
- bits = bits.mod(q)
- var out = Buffer.from(bits.toArray())
- if (out.length < q.byteLength()) {
- var zeros = Buffer.alloc(q.byteLength() - out.length)
- out = Buffer.concat([zeros, out])
- }
- return out
- }
- function makeKey (q, kv, algo) {
- var t
- var k
- do {
- t = Buffer.alloc(0)
- while (t.length * 8 < q.bitLength()) {
- kv.v = createHmac(algo, kv.k).update(kv.v).digest()
- t = Buffer.concat([t, kv.v])
- }
- k = bits2int(t, q)
- kv.k = createHmac(algo, kv.k).update(kv.v).update(Buffer.from([0])).digest()
- kv.v = createHmac(algo, kv.k).update(kv.v).digest()
- } while (k.cmp(q) !== -1)
- return k
- }
- function makeR (g, k, p, q) {
- return g.toRed(BN.mont(p)).redPow(k).fromRed().mod(q)
- }
- module.exports = sign
- module.exports.getKey = getKey
- module.exports.makeKey = makeKey
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