96 lines
2.8 KiB
JavaScript
96 lines
2.8 KiB
JavaScript
;(function () {
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'use strict';
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var createHash = require('create-hash');
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var pbkdf2 = require('pbkdf2');
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var aes = require('browserify-aes');
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var ec = require('elliptic').ec('p256');
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function sha256(buf) {
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return createHash('sha256').update(buf).digest();
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}
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function runPbkdf2(password, salt) {
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// Derived AES key is 128 bit, and the function takes a size in bytes.
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return pbkdf2.pbkdf2Sync(password, Buffer(salt), 8192, 16, 'sha256');
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}
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function encrypt(key, iv, data) {
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var cipher = aes.createCipheriv('aes-128-gcm', Buffer(key), Buffer(iv));
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return Buffer.concat([cipher.update(Buffer(data)), cipher.final(), cipher.getAuthTag()]);
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}
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function decrypt(key, iv, data) {
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var decipher = aes.createDecipheriv('aes-128-gcm', Buffer(key), Buffer(iv));
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decipher.setAuthTag(Buffer(data.slice(-16)));
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return Buffer.concat([decipher.update(Buffer(data.slice(0, -16))), decipher.final()]);
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}
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function bnToB64(bn) {
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if (bn.red) {
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bn = bn.fromRed();
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}
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var b64 = bn.toArrayLike(Buffer).toString('base64');
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return b64.replace(/\+/g, '-').replace(/\//g, '_').replace(/=*$/, '');
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}
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function genEcdsaKeyPair() {
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var key = ec.genKeyPair();
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var pubJwk = {
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key_ops: ['verify']
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, kty: 'EC'
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, crv: 'P-256'
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, x: bnToB64(key.getPublic().x)
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, y: bnToB64(key.getPublic().y)
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};
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var privJwk = JSON.parse(JSON.stringify(pubJwk));
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privJwk.key_ops = ['sign'];
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privJwk.d = bnToB64(key.getPrivate());
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return {privateKey: privJwk, publicKey: pubJwk};
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}
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function bnToBuffer(bn, size) {
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var buf = bn.toArrayLike(Buffer);
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if (!size || buf.length === size) {
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return buf;
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}
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if (buf > size) {
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throw new Error("EC signature number bigger than expected");
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}
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return Buffer.concat([Buffer(size-buf.length).fill(0), buf]);
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}
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function sign(jwk, msg) {
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var key = ec.keyFromPrivate(Buffer(jwk.d, 'base64'));
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var sig = key.sign(sha256(msg));
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return Buffer.concat([bnToBuffer(sig.r, 32), bnToBuffer(sig.s, 32)]);
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}
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function verify(jwk, msg, signature) {
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var key = ec.keyFromPublic({x: Buffer(jwk.x, 'base64'), y: Buffer(jwk.y, 'base64')});
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var sig = {
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r: Buffer(signature.slice(0, signature.length/2))
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, s: Buffer(signature.slice(signature.length/2))
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};
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return key.verify(sha256(msg), sig);
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}
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function promiseWrap(func) {
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return function() {
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var args = arguments;
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return new Promise(function (resolve) {
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resolve(func.apply(null, args));
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});
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};
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}
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exports.sha256 = promiseWrap(sha256);
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exports.pbkdf2 = promiseWrap(runPbkdf2);
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exports.encrypt = promiseWrap(encrypt);
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exports.decrypt = promiseWrap(decrypt);
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exports.sign = promiseWrap(sign);
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exports.verify = promiseWrap(verify);
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exports.genEcdsaKeyPair = promiseWrap(genEcdsaKeyPair);
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}());
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