109 lines
2.3 KiB
JavaScript
109 lines
2.3 KiB
JavaScript
/*!
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* pbkdf2.js - pbkdf2 for bcoin
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* Copyright (c) 2014-2017, Christopher Jeffrey (MIT License).
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* https://github.com/bcoin-org/bcoin
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*/
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'use strict';
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/**
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* @module crypto.pbkdf2-browser
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* @ignore
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*/
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var digest = require('./digest');
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var crypto = global.crypto || global.msCrypto || {};
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var subtle = crypto.subtle && crypto.subtle.importKey ? crypto.subtle : {};
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/**
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* Perform key derivation using PBKDF2.
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* @param {Buffer} key
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* @param {Buffer} salt
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* @param {Number} iter
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* @param {Number} len
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* @param {String} alg
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* @returns {Buffer}
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*/
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exports.derive = function derive(key, salt, iter, len, alg) {
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var size = digest.hash(alg, Buffer.alloc(0)).length;
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var blocks = Math.ceil(len / size);
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var out = Buffer.allocUnsafe(len);
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var buf = Buffer.allocUnsafe(salt.length + 4);
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var block = Buffer.allocUnsafe(size);
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var pos = 0;
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var i, j, k, mac;
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salt.copy(buf, 0);
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for (i = 0; i < blocks; i++) {
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buf.writeUInt32BE(i + 1, salt.length, true);
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mac = digest.hmac(alg, buf, key);
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mac.copy(block, 0);
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for (j = 1; j < iter; j++) {
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mac = digest.hmac(alg, mac, key);
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for (k = 0; k < size; k++)
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block[k] ^= mac[k];
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}
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block.copy(out, pos);
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pos += size;
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}
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return out;
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};
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/**
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* Execute pbkdf2 asynchronously.
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* @param {Buffer} key
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* @param {Buffer} salt
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* @param {Number} iter
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* @param {Number} len
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* @param {String} alg
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* @returns {Promise}
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*/
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exports.deriveAsync = function deriveAsync(key, salt, iter, len, alg) {
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var algo = { name: 'PBKDF2' };
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var use = ['deriveBits'];
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var name = getHash(alg);
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var length = len * 8;
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var options, promise;
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options = {
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name: 'PBKDF2',
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salt: salt,
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iterations: iter,
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hash: name
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};
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promise = subtle.importKey('raw', key, algo, false, use);
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return promise.then(function(key) {
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return subtle.deriveBits(options, key, length);
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}).then(function(result) {
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return Buffer.from(result);
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});
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};
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if (!subtle.deriveBits)
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exports.pbkdf2Async = exports.pbkdf2;
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/*
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* Helpers
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*/
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function getHash(name) {
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switch (name) {
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case 'sha1':
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return 'SHA-1';
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case 'sha256':
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return 'SHA-256';
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case 'sha384':
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return 'SHA-384';
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case 'sha512':
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return 'SHA-512';
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default:
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throw new Error('Algorithm not supported: ' + name);
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}
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}
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