123 lines
2.5 KiB
JavaScript
123 lines
2.5 KiB
JavaScript
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var elliptic = require('elliptic');
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var BN = require('bn.js');
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module.exports = function createECDH(curve) {
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return new ECDH(curve);
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};
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var aliases = {
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secp256k1: {
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name: 'secp256k1',
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byteLength: 32
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},
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secp224r1: {
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name: 'p224',
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byteLength: 28
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},
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prime256v1: {
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name: 'p256',
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byteLength: 32
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},
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prime192v1: {
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name: 'p192',
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byteLength: 24
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},
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ed25519: {
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name: 'ed25519',
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byteLength: 32
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},
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secp384r1: {
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name: 'p384',
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byteLength: 48
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},
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secp521r1: {
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name: 'p521',
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byteLength: 66
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}
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};
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aliases.p224 = aliases.secp224r1;
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aliases.p256 = aliases.secp256r1 = aliases.prime256v1;
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aliases.p192 = aliases.secp192r1 = aliases.prime192v1;
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aliases.p384 = aliases.secp384r1;
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aliases.p521 = aliases.secp521r1;
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function ECDH(curve) {
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this.curveType = aliases[curve];
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if (!this.curveType ) {
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this.curveType = {
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name: curve
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};
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}
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this.curve = new elliptic.ec(this.curveType.name);
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this.keys = void 0;
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}
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ECDH.prototype.generateKeys = function (enc, format) {
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this.keys = this.curve.genKeyPair();
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return this.getPublicKey(enc, format);
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};
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ECDH.prototype.computeSecret = function (other, inenc, enc) {
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inenc = inenc || 'utf8';
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if (!Buffer.isBuffer(other)) {
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other = new Buffer(other, inenc);
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}
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var otherPub = this.curve.keyFromPublic(other).getPublic();
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var out = otherPub.mul(this.keys.getPrivate()).getX();
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return formatReturnValue(out, enc, this.curveType.byteLength);
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};
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ECDH.prototype.getPublicKey = function (enc, format) {
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var key = this.keys.getPublic(format === 'compressed', true);
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if (format === 'hybrid') {
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if (key[key.length - 1] % 2) {
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key[0] = 7;
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} else {
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key [0] = 6;
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}
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}
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return formatReturnValue(key, enc);
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};
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ECDH.prototype.getPrivateKey = function (enc) {
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return formatReturnValue(this.keys.getPrivate(), enc);
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};
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ECDH.prototype.setPublicKey = function (pub, enc) {
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enc = enc || 'utf8';
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if (!Buffer.isBuffer(pub)) {
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pub = new Buffer(pub, enc);
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}
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this.keys._importPublic(pub);
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return this;
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};
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ECDH.prototype.setPrivateKey = function (priv, enc) {
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enc = enc || 'utf8';
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if (!Buffer.isBuffer(priv)) {
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priv = new Buffer(priv, enc);
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}
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var _priv = new BN(priv);
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_priv = _priv.toString(16);
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this.keys._importPrivate(_priv);
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return this;
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};
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function formatReturnValue(bn, enc, len) {
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if (!Array.isArray(bn)) {
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bn = bn.toArray();
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}
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var buf = new Buffer(bn);
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if (len && buf.length < len) {
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var zeros = new Buffer(len - buf.length);
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zeros.fill(0);
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buf = Buffer.concat([zeros, buf]);
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}
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if (!enc) {
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return buf;
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} else {
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return buf.toString(enc);
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}
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}
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