import {
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Base,
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WordArray,
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} from './core.js';
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import { MD5Algo } from './md5.js';
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/**
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* This key derivation function is meant to conform with EVP_BytesToKey.
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* www.openssl.org/docs/crypto/EVP_BytesToKey.html
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*/
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export class EvpKDFAlgo extends Base {
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/**
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* Initializes a newly created key derivation function.
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*
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* @param {Object} cfg (Optional) The configuration options to use for the derivation.
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*
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* @example
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*
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* const kdf = CryptoJS.algo.EvpKDF.create();
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* const kdf = CryptoJS.algo.EvpKDF.create({ keySize: 8 });
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* const kdf = CryptoJS.algo.EvpKDF.create({ keySize: 8, iterations: 1000 });
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*/
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constructor(cfg) {
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super();
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/**
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* Configuration options.
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*
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* @property {number} keySize The key size in words to generate. Default: 4 (128 bits)
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* @property {Hasher} hasher The hash algorithm to use. Default: MD5
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* @property {number} iterations The number of iterations to perform. Default: 1
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*/
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this.cfg = Object.assign(
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new Base(),
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{
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keySize: 128 / 32,
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hasher: MD5Algo,
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iterations: 1,
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},
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cfg,
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);
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}
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/**
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* Derives a key from a password.
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*
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* @param {WordArray|string} password The password.
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* @param {WordArray|string} salt A salt.
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*
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* @return {WordArray} The derived key.
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*
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* @example
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*
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* const key = kdf.compute(password, salt);
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*/
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compute(password, salt) {
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let block;
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// Shortcut
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const { cfg } = this;
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// Init hasher
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const hasher = cfg.hasher.create();
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// Initial values
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const derivedKey = WordArray.create();
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// Shortcuts
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const derivedKeyWords = derivedKey.words;
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const { keySize, iterations } = cfg;
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// Generate key
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while (derivedKeyWords.length < keySize) {
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if (block) {
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hasher.update(block);
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}
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block = hasher.update(password).finalize(salt);
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hasher.reset();
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// Iterations
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for (let i = 1; i < iterations; i += 1) {
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block = hasher.finalize(block);
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hasher.reset();
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}
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derivedKey.concat(block);
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}
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derivedKey.sigBytes = keySize * 4;
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return derivedKey;
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}
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}
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/**
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* Derives a key from a password.
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*
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* @param {WordArray|string} password The password.
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* @param {WordArray|string} salt A salt.
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* @param {Object} cfg (Optional) The configuration options to use for this computation.
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*
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* @return {WordArray} The derived key.
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*
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* @static
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*
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* @example
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*
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* var key = CryptoJS.EvpKDF(password, salt);
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* var key = CryptoJS.EvpKDF(password, salt, { keySize: 8 });
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* var key = CryptoJS.EvpKDF(password, salt, { keySize: 8, iterations: 1000 });
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*/
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export const EvpKDF = (password, salt, cfg) => EvpKDFAlgo.create(cfg).compute(password, salt);
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