118 lines
3.0 KiB
JavaScript
118 lines
3.0 KiB
JavaScript
'use strict';
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var coinUtil = require('../../util');
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var Point = require('../Point');
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var SecureRandom = require('../SecureRandom');
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var Key = require('../Key');
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// http://en.wikipedia.org/wiki/Integrated_Encryption_Scheme
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var ECIES = function() {};
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ECIES.encryptObj = function(pubkey, message, r, iv) {
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var ecies = new ECIES();
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ecies.KB = pubkey;
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ecies.message = message;
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r = ecies.getRandomSeed(r);
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var R = ecies.R;
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var S = ecies.S = ecies.getSfromPubkey();
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var buf = ECIES.kdf(S);
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var kE = ecies.kE = buf.slice(0, 32);
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var kM = ecies.kM = buf.slice(32, 64);
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iv = iv || SecureRandom.getRandomBuffer(16);
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var c = ecies.c = ECIES.symmetricEncrypt(kE, iv, message);
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var d = ecies.d = ECIES.mac(kM, c);
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return ecies;
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};
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ECIES.encrypt = function(pubkey, message, r, iv) {
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var ecies = ECIES.encryptObj(pubkey, message, r, iv);
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var key = new Key();
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key.compressed = false;
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key.public = ecies.R.toUncompressedPubKey();
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key.compressed = true;
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var Rbuf = key.public;
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var buf = Buffer.concat([Rbuf, ecies.c, ecies.d]);
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return buf;
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};
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ECIES.decryptObj = function(ecies) {
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var kB = ecies.kB;
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var R = ecies.R;
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var c = ecies.c;
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var d = ecies.d;
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var P = Point.multiply(R, kB);
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var S = P.x.toBuffer({
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size: 32
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});
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var buf = ECIES.kdf(S);
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var kE = ecies.kE = buf.slice(0, 32);
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var kM = ecies.kM = buf.slice(32, 64);
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var d2 = ECIES.mac(kM, c);
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if (d.toString('hex') !== d2.toString('hex'))
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throw new Error('MAC check incorrect. Data is invalid.');
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var decrypted = ECIES.symmetricDecrypt(kE, c);
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return decrypted;
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};
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ECIES.decrypt = function(privkey, buf) {
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if (buf.length < 33 + 0 + 64)
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throw new Error('invalid length of encrypted data');
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var ecies = new ECIES();
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ecies.kB = privkey;
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var Rbuf = buf.slice(0, 33);
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var key = new Key();
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key.public = Rbuf;
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key.compressed = false;
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ecies.R = Point.fromUncompressedPubKey(key.public);
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ecies.c = buf.slice(33, buf.length - 64);
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ecies.d = buf.slice(buf.length - 64, buf.length);
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return ECIES.decryptObj(ecies);
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};
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ECIES.kdf = function(S) {
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var buf = coinUtil.sha512(S);
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return buf;
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};
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ECIES.mac = function(data, key) {
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var buf = coinUtil.sha512hmac(data, key);
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return buf;
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};
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ECIES.prototype.getRandomSeed = function(r) {
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if (r) {
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this.key = new Key();
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this.key.private = r;
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this.key.regenerateSync();
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} else {
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this.key = Key.generateSync();
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};
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this.r = this.key.private;
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this.key.compressed = false;
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this.R = Point.fromUncompressedPubKey(this.key.public);
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return this.r;
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};
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ECIES.prototype.getSfromPubkey = function() {
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var key2 = new Key();
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key2.public = this.KB;
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key2.compressed = false;
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var KBP = Point.fromUncompressedPubKey(key2.public);
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this.P = Point.multiply(KBP, this.r);
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this.S = this.P.x.toBuffer({
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size: 32
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});
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return this.S;
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};
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ECIES.prototype.getSfromPrivkey = function() {
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var R = this.R;
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var kB = this.kB;
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var SP = Point.multiply(R, kB);
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var S = SP.x.toBuffer({
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size: 32
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});
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return S;
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};
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module.exports = ECIES;
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