videojs-contrib-hls
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Play back HLS with video.js, even where it's not natively supported.
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JavaScript
/*
*
* 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.
*/
(function(window, videojs, unpad) {
;
var AES, AsyncStream, Decrypter, decrypt, ntoh;
/**
* Convert network-order (big-endian) bytes into their little-endian
* representation.
*/
ntoh = function(word) {
return (word << 24) |
((word & 0xff00) << 8) |
((word & 0xff0000) >> 8) |
(word >>> 24);
};
/**
* Schedule out an AES key for both encryption and decryption. This
* is a low-level class. Use a cipher mode to do bulk encryption.
*
* @constructor
* @param key {Array} The key as an array of 4, 6 or 8 words.
*/
AES = function (key) {
this._precompute();
var i, j, tmp,
encKey, decKey,
sbox = this._tables[0][4], decTable = this._tables[1],
keyLen = key.length, rcon = 1;
if (keyLen !== 4 && keyLen !== 6 && keyLen !== 8) {
throw new Error("Invalid aes key size");
}
encKey = key.slice(0);
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]];
}
}
};
AES.prototype = {
/**
* 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
*/
_tables: [[[],[],[],[],[]],[[],[],[],[],[]]],
/**
* Expand the S-box tables.
*
* @private
*/
_precompute: function () {
var encTable = this._tables[0], decTable = this._tables[1],
sbox = encTable[4], sboxInv = decTable[4],
i, x, xInv, d=[], th=[], x2, x4, x8, s, tEnc, 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);
}
},
/**
* Decrypt 16 bytes, specified as four 32-bit words.
* @param encrypted0 {number} the first word to decrypt
* @param encrypted1 {number} the second word to decrypt
* @param encrypted2 {number} the third word to decrypt
* @param encrypted3 {number} the fourth word to decrypt
* @param out {Int32Array} the array to write the decrypted words
* into
* @param offset {number} the offset into the output array to start
* writing results
* @return {Array} The plaintext.
*/
decrypt:function (encrypted0, encrypted1, encrypted2, encrypted3, out, offset) {
var key = this._key[1],
// state variables a,b,c,d are loaded with pre-whitened data
a = encrypted0 ^ key[0],
b = encrypted3 ^ key[1],
c = encrypted2 ^ key[2],
d = encrypted1 ^ key[3],
a2, b2, c2,
nInnerRounds = key.length / 4 - 2, // key.length === 2 ?
i,
kIndex = 4,
table = this._tables[1],
// load up the tables
table0 = table[0],
table1 = table[1],
table2 = table[2],
table3 = table[3],
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;
}
}
};
/**
* Decrypt bytes using AES-128 with CBC and PKCS#7 padding.
* @param encrypted {Uint8Array} the encrypted bytes
* @param key {Uint32Array} the bytes of the decryption key
* @param initVector {Uint32Array} 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
*/
decrypt = function(encrypted, key, initVector) {
var
// word-level access to the encrypted bytes
encrypted32 = new Int32Array(encrypted.buffer, encrypted.byteOffset, encrypted.byteLength >> 2),
decipher = new AES(Array.prototype.slice.call(key)),
// byte and word-level access for the decrypted output
decrypted = new Uint8Array(encrypted.byteLength),
decrypted32 = new Int32Array(decrypted.buffer),
// temporary variables for working with the IV, encrypted, and
// decrypted data
init0, init1, init2, init3,
encrypted0, encrypted1, encrypted2, encrypted3,
// iteration variable
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;
};
AsyncStream = function() {
this.jobs = [];
this.delay = 1;
this.timeout_ = null;
};
AsyncStream.prototype = new videojs.Hls.Stream();
AsyncStream.prototype.processJob_ = function() {
this.jobs.shift()();
if (this.jobs.length) {
this.timeout_ = setTimeout(this.processJob_.bind(this),
this.delay);
} else {
this.timeout_ = null;
}
};
AsyncStream.prototype.push = function(job) {
this.jobs.push(job);
if (!this.timeout_) {
this.timeout_ = setTimeout(this.processJob_.bind(this),
this.delay);
}
};
Decrypter = function(encrypted, key, initVector, done) {
var
step = Decrypter.STEP,
encrypted32 = new Int32Array(encrypted.buffer),
decrypted = new Uint8Array(encrypted.byteLength),
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, unpad(decrypted));
});
};
Decrypter.prototype = new videojs.Hls.Stream();
Decrypter.prototype.decryptChunk_ = function(encrypted, key, initVector, decrypted) {
return function() {
var bytes = decrypt(encrypted,
key,
initVector);
decrypted.set(bytes, encrypted.byteOffset);
};
};
// the maximum number of bytes to process at one time
Decrypter.STEP = 4 * 8000;
// exports
videojs.Hls.decrypt = decrypt;
videojs.Hls.Decrypter = Decrypter;
videojs.Hls.AsyncStream = AsyncStream;
})(window, window.videojs, window.pkcs7.unpad);