/* -*- Mode: Java; tab-width: s; indent-tabs-mode: nil; c-basic-offset: 2 -*- /
/* vim: set shiftwidth=s tabstop=2 autoindent cindent expandtab: */
"use strict";
var ARCFourCipher = (function() {
function constructor(key) {
this.a = 0;
this.b = 0;
var s = new Uint8Array(256);
var i, j = 0, tmp, keyLength = key.length;
for (i = 0; i < 256; ++i)
s[i] = i;
for (i = 0; i < 256; ++i) {
tmp = s[i];
j = (j + tmp + key[i % keyLength]) & 0xFF;
s[i] = s[j];
s[j] = tmp;
}
this.s = s;
}
constructor.prototype = {
encryptBlock: function(data) {
var i, n = data.length, tmp, tmp2;
var a = this.a, b = this.b, s = this.s;
var output = new Uint8Array(n);
for (i = 0; i < n; ++i) {
var tmp;
a = (a + 1) & 0xFF;
tmp = s[a];
b = (b + tmp) & 0xFF;
tmp2 = s[b]
s[a] = tmp2;
s[b] = tmp;
output[i] = data[i] ^ s[(tmp + tmp2) & 0xFF];
}
this.a = a;
this.b = b;
return output;
}
};
return constructor;
})();
var md5 = (function() {
const r = new Uint8Array([
7, 12, 17, 22, 7, 12, 17, 22, 7, 12, 17, 22, 7, 12, 17, 22,
5, 9, 14, 20, 5, 9, 14, 20, 5, 9, 14, 20, 5, 9, 14, 20,
4, 11, 16, 23, 4, 11, 16, 23, 4, 11, 16, 23, 4, 11, 16, 23,
6, 10, 15, 21, 6, 10, 15, 21, 6, 10, 15, 21, 6, 10, 15, 21]);
const k = new Int32Array([
-680876936, -389564586, 606105819, -1044525330, -176418897, 1200080426,
-1473231341, -45705983, 1770035416, -1958414417, -42063, -1990404162,
1804603682, -40341101, -1502002290, 1236535329, -165796510, -1069501632,
643717713, -373897302, -701558691, 38016083, -660478335, -405537848, 568446438,
-1019803690, -187363961, 1163531501, -1444681467, -51403784, 1735328473,
-1926607734, -378558, -2022574463, 1839030562, -35309556, -1530992060,
1272893353, -155497632, -1094730640, 681279174, -358537222, -722521979,
76029189, -640364487, -421815835, 530742520, -995338651, -198630844, 1126891415,
-1416354905, -57434055, 1700485571, -1894986606, -1051523, -2054922799,
1873313359, -30611744, -1560198380, 1309151649, -145523070, -1120210379,
718787259, -343485551]);
function hash(data, offset, length) {
var h0 = 1732584193, h1 = -271733879, h2 = -1732584194, h3 = 271733878;
// pre-processing
var paddedLength = (length + 72) & ~63; // data + 9 extra bytes
var padded = new Uint8Array(paddedLength);
var i, j, n;
for (i = 0; i < length; ++i)
padded[i] = data[offset++];
padded[i++] = 0x80;
n = paddedLength - 8;
for (; i < n; ++i)
padded[i] = 0;
padded[i++] = (length << 3) & 0xFF;
padded[i++] = (length >> 5) & 0xFF;
padded[i++] = (length >> 13) & 0xFF;
padded[i++] = (length >> 21) & 0xFF;
padded[i++] = (length >>> 29) & 0xFF;
padded[i++] = 0;
padded[i++] = 0;
padded[i++] = 0;
// chunking
// TODO ArrayBuffer ?
var w = new Int32Array(16);
for (i = 0; i < paddedLength;) {
for (j = 0; j < 16; ++j, i += 4)
w[j] = padded[i] | (padded[i + 1] << 8) | (padded[i + 2] << 16) | (padded[i + 3] << 24);
var a = h0, b = h1, c = h2, d = h3, f, g;
for (j = 0; j < 64; ++j) {
if (j < 16) {
f = (b & c) | ((~b) & d);
g = j;
} else if (j < 32) {
f = (d & b) | ((~d) & c);
g = (5 * j + 1) & 15;
} else if (j < 48) {
f = b ^ c ^ d;
g = (3 * j + 5) & 15;
} else {
f = c ^ (b | (~d));
g = (7 * j) & 15;
}
var tmp = d, rotateArg = (a + f + k[j] + w[g]) | 0, rotate = r[j];
d = c;
c = b;
b = (b + ((rotateArg << rotate) | (rotateArg >>> (32 - rotate)))) | 0;
a = tmp;
}
h0 = (h0 + a) | 0;
h1 = (h1 + b) | 0;
h2 = (h2 + c) | 0;
h3 = (h3 + d) | 0;
}
return new Uint8Array([
h0 & 0xFF, (h0 >> 8) & 0xFF, (h0 >> 16) & 0xFF, (h0 >>> 24) & 0xFF,
h1 & 0xFF, (h1 >> 8) & 0xFF, (h1 >> 16) & 0xFF, (h1 >>> 24) & 0xFF,
h2 & 0xFF, (h2 >> 8) & 0xFF, (h2 >> 16) & 0xFF, (h2 >>> 24) & 0xFF,
h3 & 0xFF, (h3 >> 8) & 0xFF, (h3 >> 16) & 0xFF, (h3 >>> 24) & 0xFF
]);
}
return hash;
})();
var CipherTransform = (function() {
function constructor(stringCipherConstructor, streamCipherConstructor) {
this.stringCipherConstructor = stringCipherConstructor;
this.streamCipherConstructor = streamCipherConstructor;
}
constructor.prototype = {
createStream: function (stream) {
var cipher = new this.streamCipherConstructor();
return new DecryptStream(stream, function(data) {
return cipher.encryptBlock(data);
});
},
decryptString: function(s) {
var cipher = new this.stringCipherConstructor();
var data = string2bytes(s);
data = cipher.encryptBlock(data);
return bytes2string(data);
}
};
return constructor;
})();
var CipherTransformFactory = (function() {
function prepareKeyData(fileId, password, ownerPassword, userPassword, flags, revision, keyLength) {
const defaultPasswordBytes = new Uint8Array([
0x28, 0xBF, 0x4E, 0x5E, 0x4E, 0x75, 0x8A, 0x41, 0x64, 0x00, 0x4E, 0x56, 0xFF, 0xFA, 0x01, 0x08,
0x2E, 0x2E, 0x00, 0xB6, 0xD0, 0x68, 0x3E, 0x80, 0x2F, 0x0C, 0xA9, 0xFE, 0x64, 0x53, 0x69, 0x7A]);
var hashData = new Uint8Array(88), i = 0, j, n;
if (password) {
n = Math.min(32, password.length);
for (; i < n; ++i)
hashData[i] = password[i];
}
j = 0;
while (i < 32) {
hashData[i++] = defaultPasswordBytes[j++];
}
// as now the padded password in the hashData[0..i]
for (j = 0, n = ownerPassword.length; j < n; ++j)
hashData[i++] = ownerPassword[j];
hashData[i++] = flags & 0xFF;
hashData[i++] = (flags >> 8) & 0xFF;
hashData[i++] = (flags >> 16) & 0xFF;
hashData[i++] = (flags >>> 24) & 0xFF;
for (j = 0, n = fileId.length; j < n; ++j)
hashData[i++] = fileId[j];
// TODO rev 4, if metadata is not encrypted pass 0xFFFFFF also
var hash = md5(hashData, 0, i);
var keyLengthInBytes = keyLength >> 3;
if (revision >= 3) {
for (j = 0; j < 50; ++j) {
hash = md5(hash, 0, keyLengthInBytes);
}
}
var encryptionKey = hash.subarray(0, keyLengthInBytes);
var cipher, checkData;
if (revision >= 3) {
// padded password in hashData, we can use this array for user password check
i = 32;
for(j = 0, n = fileId.length; j < n; ++j)
hashData[i++] = fileId[j];
cipher = new ARCFourCipher(encryptionKey);
var checkData = cipher.encryptBlock(md5(hashData, 0, i));
n = encryptionKey.length;
var derrivedKey = new Uint8Array(n), k;
for (j = 1; j <= 19; ++j) {
for (k = 0; k < n; ++k)
derrivedKey[k] = encryptionKey[k] ^ j;
cipher = new ARCFourCipher(derrivedKey);
checkData = cipher.encryptBlock(checkData);
}
} else {
cipher = new ARCFourCipher(encryptionKey);
checkData = cipher.encryptBlock(hashData.subarray(0, 32));
}
for (j = 0, n = checkData.length; j < n; ++j) {
if (userPassword[j] != checkData[j])
error("incorrect password");
}
return encryptionKey;
}
function constructor(dict, fileId, password) {
var filter = dict.get("Filter");
if (!IsName(filter) || filter.name != "Standard")
error("unknown encryption method");
this.dict = dict;
var algorithm = dict.get("V");
if (!IsInt(algorithm) ||
(algorithm != 1 && algorithm != 2))
error("unsupported encryption algorithm");
// TODO support algorithm 4
var keyLength = dict.get("Length") || 40;
if (!IsInt(keyLength) ||
keyLength < 40 || (keyLength % 8) != 0)
error("invalid key length");
// prepare keys
var ownerPassword = stringToBytes(dict.get("O"));
var userPassword = stringToBytes(dict.get("U"));
var flags = dict.get("P");
var revision = dict.get("R");
var fileIdBytes = stringToBytes(fileId);
var passwordBytes;
if (password)
passwordBytes = stringToBytes(password);
this.encryptionKey = prepareKeyData(fileIdBytes, passwordBytes,
ownerPassword, userPassword, flags, revision, keyLength);
}
constructor.prototype = {
createCipherTransform: function(num, gen) {
var encryptionKey = this.encryptionKey;
var key = new Uint8Array(encryptionKey.length + 5), i, n;
for (i = 0, n = encryptionKey.length; i < n; ++i)
key[i] = encryptionKey[i];
key[i++] = num & 0xFF;
key[i++] = (num >> 8) & 0xFF;
key[i++] = (num >> 16) & 0xFF;
key[i++] = gen & 0xFF;
key[i++] = (gen >> 8) & 0xFF;
var hash = md5(key, 0, i);
key = hash.subarray(0, Math.min(key.length, 16));
var cipherConstructor = function() {
return new ARCFourCipher(key);
};
return new CipherTransform(cipherConstructor, cipherConstructor);
}
};
return constructor;
})();