54 lines
1.5 KiB
JavaScript
54 lines
1.5 KiB
JavaScript
/**
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* Browser eccrypto implementation.
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*/
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// NOTE(Kagami): We don't use promise shim in Browser implementation
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// because it's supported natively in new browsers (see
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// <http://caniuse.com/#feat=promises>) and we can use only new browsers
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// because of the WebCryptoAPI (see
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// <http://caniuse.com/#feat=cryptography>).
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"use strict";
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var EC = require("elliptic").ec;
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var ec = new EC("secp256k1");
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function assert(condition, message) {
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if (!condition) {
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throw new Error(message || "Assertion failed");
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}
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}
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exports.getPublic = function(privateKey) {
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// This function has sync API so we throw an error immediately.
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// (`elliptic` doesn't do this).
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assert(privateKey.length === 32, "Bad private key");
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// XXX(Kagami): `elliptic.utils.encode` returns array for every
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// encoding except `hex`.
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return new Buffer(ec.keyPair(privateKey).getPublic("arr"));
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};
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exports.sign = function(privateKey, msg) {
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return new Promise(function(resolve) {
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var key = ec.keyPair(privateKey);
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resolve(new Buffer(key.sign(msg).toDER()));
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});
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};
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exports.verify = function(key, msg, sig) {
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return new Promise(function(resolve, reject) {
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key = ec.keyPair(key);
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return key.verify(msg, sig) ? resolve() : reject();
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});
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};
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exports.derive = function(privateKeyA, publicKeyB) {
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return new Promise(function(resolve) {
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var keyA = ec.keyPair(privateKeyA);
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var keyB = ec.keyPair(publicKeyB);
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var Px = keyA.derive(keyB.getPublic()); // BN instance
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resolve(new Buffer(Px.toString(16), "hex"));
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});
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};
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