Duffer Derek

/*! @name aes-decrypter @version 4.0.2 @license Apache-2.0 */
'use strict';

Object.defineProperty(exports, '__esModule', { value: true });

var Stream = require('@videojs/vhs-utils/cjs/stream.js');
var pkcs7 = require('pkcs7');

function _interopDefaultLegacy (e) { return e && typeof e === 'object' && 'default' in e ? e : { 'default': e }; }

var Stream__default = /*#__PURE__*/_interopDefaultLegacy(Stream);

/**
 * @file aes.js
 *
 * This file contains an adaptation of the AES decryption algorithm
 * from the Standford Javascript Cryptography Library. That work is
 * covered by the following copyright and permissions notice:
 *
 * Copyright 2009-2010 Emily Stark, Mike Hamburg, Dan Boneh.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above
 *    copyright notice, this list of conditions and the following
 *    disclaimer in the documentation and/or other materials provided
 *    with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
 * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * The views and conclusions contained in the software and documentation
 * are those of the authors and should not be interpreted as representing
 * official policies, either expressed or implied, of the authors.
 */

/**
 * Expand the S-box tables.
 *
 * @private
 */
const precompute = function () {
  const tables = [[[], [], [], [], []], [[], [], [], [], []]];
  const encTable = tables[0];
  const decTable = tables[1];
  const sbox = encTable[4];
  const sboxInv = decTable[4];
  let i;
  let x;
  let xInv;
  const d = [];
  const th = [];
  let x2;
  let x4;
  let x8;
  let s;
  let tEnc;
  let tDec; // Compute double and third tables

  for (i = 0; i < 256; i++) {
    th[(d[i] = i << 1 ^ (i >> 7) * 283) ^ i] = i;
  }

  for (x = xInv = 0; !sbox[x]; x ^= x2 || 1, xInv = th[xInv] || 1) {
    // Compute sbox
    s = xInv ^ xInv << 1 ^ xInv << 2 ^ xInv << 3 ^ xInv << 4;
    s = s >> 8 ^ s & 255 ^ 99;
    sbox[x] = s;
    sboxInv[s] = x; // Compute MixColumns

    x8 = d[x4 = d[x2 = d[x]]];
    tDec = x8 * 0x1010101 ^ x4 * 0x10001 ^ x2 * 0x101 ^ x * 0x1010100;
    tEnc = d[s] * 0x101 ^ s * 0x1010100;

    for (i = 0; i < 4; i++) {
      encTable[i][x] = tEnc = tEnc << 24 ^ tEnc >>> 8;
      decTable[i][s] = tDec = tDec << 24 ^ tDec >>> 8;
    }
  } // Compactify. Considerable speedup on Firefox.


  for (i = 0; i < 5; i++) {
    encTable[i] = encTable[i].slice(0);
    decTable[i] = decTable[i].slice(0);
  }

  return tables;
};

let aesTables = null;
/**
 * Schedule out an AES key for both encryption and decryption. This
 * is a low-level class. Use a cipher mode to do bulk encryption.
 *
 * @class AES
 * @param key {Array} The key as an array of 4, 6 or 8 words.
 */

class AES {
  constructor(key) {
    /**
    * The expanded S-box and inverse S-box tables. These will be computed
    * on the client so that we don't have to send them down the wire.
    *
    * There are two tables, _tables[0] is for encryption and
    * _tables[1] is for decryption.
    *
    * The first 4 sub-tables are the expanded S-box with MixColumns. The
    * last (_tables[01][4]) is the S-box itself.
    *
    * @private
    */
    // if we have yet to precompute the S-box tables
    // do so now
    if (!aesTables) {
      aesTables = precompute();
    } // then make a copy of that object for use


    this._tables = [[aesTables[0][0].slice(), aesTables[0][1].slice(), aesTables[0][2].slice(), aesTables[0][3].slice(), aesTables[0][4].slice()], [aesTables[1][0].slice(), aesTables[1][1].slice(), aesTables[1][2].slice(), aesTables[1][3].slice(), aesTables[1][4].slice()]];
    let i;
    let j;
    let tmp;
    const sbox = this._tables[0][4];
    const decTable = this._tables[1];
    const keyLen = key.length;
    let rcon = 1;

    if (keyLen !== 4 && keyLen !== 6 && keyLen !== 8) {
      throw new Error('Invalid aes key size');
    }

    const encKey = key.slice(0);
    const decKey = [];
    this._key = [encKey, decKey]; // schedule encryption keys

    for (i = keyLen; i < 4 * keyLen + 28; i++) {
      tmp = encKey[i - 1]; // apply sbox

      if (i % keyLen === 0 || keyLen === 8 && i % keyLen === 4) {
        tmp = sbox[tmp >>> 24] << 24 ^ sbox[tmp >> 16 & 255] << 16 ^ sbox[tmp >> 8 & 255] << 8 ^ sbox[tmp & 255]; // shift rows and add rcon

        if (i % keyLen === 0) {
          tmp = tmp << 8 ^ tmp >>> 24 ^ rcon << 24;
          rcon = rcon << 1 ^ (rcon >> 7) * 283;
        }
      }

      encKey[i] = encKey[i - keyLen] ^ tmp;
    } // schedule decryption keys


    for (j = 0; i; j++, i--) {
      tmp = encKey[j & 3 ? i : i - 4];

      if (i <= 4 || j < 4) {
        decKey[j] = tmp;
      } else {
        decKey[j] = decTable[0][sbox[tmp >>> 24]] ^ decTable[1][sbox[tmp >> 16 & 255]] ^ decTable[2][sbox[tmp >> 8 & 255]] ^ decTable[3][sbox[tmp & 255]];
      }
    }
  }
  /**
   * Decrypt 16 bytes, specified as four 32-bit words.
   *
   * @param {number} encrypted0 the first word to decrypt
   * @param {number} encrypted1 the second word to decrypt
   * @param {number} encrypted2 the third word to decrypt
   * @param {number} encrypted3 the fourth word to decrypt
   * @param {Int32Array} out the array to write the decrypted words
   * into
   * @param {number} offset the offset into the output array to start
   * writing results
   * @return {Array} The plaintext.
   */


  decrypt(encrypted0, encrypted1, encrypted2, encrypted3, out, offset) {
    const key = this._key[1]; // state variables a,b,c,d are loaded with pre-whitened data

    let a = encrypted0 ^ key[0];
    let b = encrypted3 ^ key[1];
    let c = encrypted2 ^ key[2];
    let d = encrypted1 ^ key[3];
    let a2;
    let b2;
    let c2; // key.length === 2 ?

    const nInnerRounds = key.length / 4 - 2;
    let i;
    let kIndex = 4;
    const table = this._tables[1]; // load up the tables

    const table0 = table[0];
    const table1 = table[1];
    const table2 = table[2];
    const table3 = table[3];
    const sbox = table[4]; // Inner rounds. Cribbed from OpenSSL.

    for (i = 0; i < nInnerRounds; i++) {
      a2 = table0[a >>> 24] ^ table1[b >> 16 & 255] ^ table2[c >> 8 & 255] ^ table3[d & 255] ^ key[kIndex];
      b2 = table0[b >>> 24] ^ table1[c >> 16 & 255] ^ table2[d >> 8 & 255] ^ table3[a & 255] ^ key[kIndex + 1];
      c2 = table0[c >>> 24] ^ table1[d >> 16 & 255] ^ table2[a >> 8 & 255] ^ table3[b & 255] ^ key[kIndex + 2];
      d = table0[d >>> 24] ^ table1[a >> 16 & 255] ^ table2[b >> 8 & 255] ^ table3[c & 255] ^ key[kIndex + 3];
      kIndex += 4;
      a = a2;
      b = b2;
      c = c2;
    } // Last round.


    for (i = 0; i < 4; i++) {
      out[(3 & -i) + offset] = sbox[a >>> 24] << 24 ^ sbox[b >> 16 & 255] << 16 ^ sbox[c >> 8 & 255] << 8 ^ sbox[d & 255] ^ key[kIndex++];
      a2 = a;
      a = b;
      b = c;
      c = d;
      d = a2;
    }
  }

}

/**
 * @file async-stream.js
 */
/**
 * A wrapper around the Stream class to use setTimeout
 * and run stream "jobs" Asynchronously
 *
 * @class AsyncStream
 * @extends Stream
 */

class AsyncStream extends Stream__default["default"] {
  constructor() {
    super(Stream__default["default"]);
    this.jobs = [];
    this.delay = 1;
    this.timeout_ = null;
  }
  /**
   * process an async job
   *
   * @private
   */


  processJob_() {
    this.jobs.shift()();

    if (this.jobs.length) {
      this.timeout_ = setTimeout(this.processJob_.bind(this), this.delay);
    } else {
      this.timeout_ = null;
    }
  }
  /**
   * push a job into the stream
   *
   * @param {Function} job the job to push into the stream
   */


  push(job) {
    this.jobs.push(job);

    if (!this.timeout_) {
      this.timeout_ = setTimeout(this.processJob_.bind(this), this.delay);
    }
  }

}

/**
 * @file decrypter.js
 *
 * An asynchronous implementation of AES-128 CBC decryption with
 * PKCS#7 padding.
 */
/**
 * Convert network-order (big-endian) bytes into their little-endian
 * representation.
 */

const ntoh = function (word) {
  return word << 24 | (word & 0xff00) << 8 | (word & 0xff0000) >> 8 | word >>> 24;
};
/**
 * Decrypt bytes using AES-128 with CBC and PKCS#7 padding.
 *
 * @param {Uint8Array} encrypted the encrypted bytes
 * @param {Uint32Array} key the bytes of the decryption key
 * @param {Uint32Array} initVector the initialization vector (IV) to
 * use for the first round of CBC.
 * @return {Uint8Array} the decrypted bytes
 *
 * @see http://en.wikipedia.org/wiki/Advanced_Encryption_Standard
 * @see http://en.wikipedia.org/wiki/Block_cipher_mode_of_operation#Cipher_Block_Chaining_.28CBC.29
 * @see https://tools.ietf.org/html/rfc2315
 */


const decrypt = function (encrypted, key, initVector) {
  // word-level access to the encrypted bytes
  const encrypted32 = new Int32Array(encrypted.buffer, encrypted.byteOffset, encrypted.byteLength >> 2);
  const decipher = new AES(Array.prototype.slice.call(key)); // byte and word-level access for the decrypted output

  const decrypted = new Uint8Array(encrypted.byteLength);
  const decrypted32 = new Int32Array(decrypted.buffer); // temporary variables for working with the IV, encrypted, and
  // decrypted data

  let init0;
  let init1;
  let init2;
  let init3;
  let encrypted0;
  let encrypted1;
  let encrypted2;
  let encrypted3; // iteration variable

  let wordIx; // pull out the words of the IV to ensure we don't modify the
  // passed-in reference and easier access

  init0 = initVector[0];
  init1 = initVector[1];
  init2 = initVector[2];
  init3 = initVector[3]; // decrypt four word sequences, applying cipher-block chaining (CBC)
  // to each decrypted block

  for (wordIx = 0; wordIx < encrypted32.length; wordIx += 4) {
    // convert big-endian (network order) words into little-endian
    // (javascript order)
    encrypted0 = ntoh(encrypted32[wordIx]);
    encrypted1 = ntoh(encrypted32[wordIx + 1]);
    encrypted2 = ntoh(encrypted32[wordIx + 2]);
    encrypted3 = ntoh(encrypted32[wordIx + 3]); // decrypt the block

    decipher.decrypt(encrypted0, encrypted1, encrypted2, encrypted3, decrypted32, wordIx); // XOR with the IV, and restore network byte-order to obtain the
    // plaintext

    decrypted32[wordIx] = ntoh(decrypted32[wordIx] ^ init0);
    decrypted32[wordIx + 1] = ntoh(decrypted32[wordIx + 1] ^ init1);
    decrypted32[wordIx + 2] = ntoh(decrypted32[wordIx + 2] ^ init2);
    decrypted32[wordIx + 3] = ntoh(decrypted32[wordIx + 3] ^ init3); // setup the IV for the next round

    init0 = encrypted0;
    init1 = encrypted1;
    init2 = encrypted2;
    init3 = encrypted3;
  }

  return decrypted;
};
/**
 * The `Decrypter` class that manages decryption of AES
 * data through `AsyncStream` objects and the `decrypt`
 * function
 *
 * @param {Uint8Array} encrypted the encrypted bytes
 * @param {Uint32Array} key the bytes of the decryption key
 * @param {Uint32Array} initVector the initialization vector (IV) to
 * @param {Function} done the function to run when done
 * @class Decrypter
 */


class Decrypter {
  constructor(encrypted, key, initVector, done) {
    const step = Decrypter.STEP;
    const encrypted32 = new Int32Array(encrypted.buffer);
    const decrypted = new Uint8Array(encrypted.byteLength);
    let i = 0;
    this.asyncStream_ = new AsyncStream(); // split up the encryption job and do the individual chunks asynchronously

    this.asyncStream_.push(this.decryptChunk_(encrypted32.subarray(i, i + step), key, initVector, decrypted));

    for (i = step; i < encrypted32.length; i += step) {
      initVector = new Uint32Array([ntoh(encrypted32[i - 4]), ntoh(encrypted32[i - 3]), ntoh(encrypted32[i - 2]), ntoh(encrypted32[i - 1])]);
      this.asyncStream_.push(this.decryptChunk_(encrypted32.subarray(i, i + step), key, initVector, decrypted));
    } // invoke the done() callback when everything is finished


    this.asyncStream_.push(function () {
      // remove pkcs#7 padding from the decrypted bytes
      done(null, pkcs7.unpad(decrypted));
    });
  }
  /**
   * a getter for step the maximum number of bytes to process at one time
   *
   * @return {number} the value of step 32000
   */


  static get STEP() {
    // 4 * 8000;
    return 32000;
  }
  /**
   * @private
   */


  decryptChunk_(encrypted, key, initVector, decrypted) {
    return function () {
      const bytes = decrypt(encrypted, key, initVector);
      decrypted.set(bytes, encrypted.byteOffset);
    };
  }

}

exports.AsyncStream = AsyncStream;
exports.Decrypter = Decrypter;
exports.decrypt = decrypt;