notmasteryet
14 years ago
3 changed files with 319 additions and 33 deletions
@ -0,0 +1,261 @@
@@ -0,0 +1,261 @@
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/* -*- Mode: Java; tab-width: s; indent-tabs-mode: nil; c-basic-offset: 2 -*- / |
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/* vim: set shiftwidth=s tabstop=2 autoindent cindent expandtab: */ |
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"use strict"; |
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var ARCFourCipher = (function() { |
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function constructor(key) { |
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var key = this.key; |
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this.a = 0; |
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this.b = 0; |
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var s = new Uint8Array(256); |
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var i, j = 0, tmp, keyLength = key.length; |
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for (i = 0; i < 256; ++i) |
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s[i] = i; |
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for (i = 0; i < 256; ++i) { |
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tmp = s[i]; |
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j = (j + tmp + key[i % keyLength]) & 0xFF; |
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s[i] = s[j]; |
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s[j] = tmp; |
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} |
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this.s = s; |
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} |
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constructor.prototype = { |
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encryptBlock: function(data) { |
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var i, n = data.length, tmp, tmp2; |
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var a = this.a, b = this.b, s = this.s; |
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var output = new Uint8Array(n); |
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for (i = 0; i < n; ++i) { |
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var tmp; |
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a = (a + 1) & 0xFF; |
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tmp = s[a]; |
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b = (b + tmp) & 0xFF; |
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tmp2 = s[b] |
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s[a] = tmp2; |
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s[b] = tmp; |
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output[i] = data[i] ^ s[(tmp + tmp2) & 0xFF]; |
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} |
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this.a = a; |
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this.b = b; |
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return output; |
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} |
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}; |
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return constructor; |
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})(); |
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var md5 = (function() { |
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const r = new Uint8Array([ |
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7, 12, 17, 22, 7, 12, 17, 22, 7, 12, 17, 22, 7, 12, 17, 22, |
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5, 9, 14, 20, 5, 9, 14, 20, 5, 9, 14, 20, 5, 9, 14, 20, |
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4, 11, 16, 23, 4, 11, 16, 23, 4, 11, 16, 23, 4, 11, 16, 23, |
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6, 10, 15, 21, 6, 10, 15, 21, 6, 10, 15, 21, 6, 10, 15, 21]); |
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const k = new Int32Array([ |
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-680876936, -389564586, 606105819, -1044525330, -176418897, 1200080426, |
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-1473231341, -45705983, 1770035416, -1958414417, -42063, -1990404162, |
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1804603682, -40341101, -1502002290, 1236535329, -165796510, -1069501632, |
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643717713, -373897302, -701558691, 38016083, -660478335, -405537848, 568446438, |
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-1019803690, -187363961, 1163531501, -1444681467, -51403784, 1735328473, |
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-1926607734, -378558, -2022574463, 1839030562, -35309556, -1530992060, |
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1272893353, -155497632, -1094730640, 681279174, -358537222, -722521979, |
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76029189, -640364487, -421815835, 530742520, -995338651, -198630844, 1126891415, |
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-1416354905, -57434055, 1700485571, -1894986606, -1051523, -2054922799, |
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1873313359, -30611744, -1560198380, 1309151649, -145523070, -1120210379, |
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718787259, -343485551]); |
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function hash(data, offset, length) { |
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var h0 = 1732584193, h1 = -271733879, h2 = -1732584194, h3 = 271733878; |
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// pre-processing
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var paddedLength = (length + 72) & ~63; // data + 9 extra bytes
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var padded = new Uint8Array(paddedLength); |
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var i, j, n; |
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for (i = 0; i < length; ++i) |
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padded[i] = data[offset++]; |
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padded[i++] = 0x80; |
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n = paddedLength - 8; |
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for (; i < n; ++i) |
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padded[i] = 0; |
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padded[i++] = (length << 3) & 0xFF; |
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padded[i++] = (length >> 5) & 0xFF; |
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padded[i++] = (length >> 13) & 0xFF; |
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padded[i++] = (length >> 21) & 0xFF; |
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padded[i++] = (length >>> 29) & 0xFF; |
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padded[i++] = 0; |
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padded[i++] = 0; |
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padded[i++] = 0; |
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// chunking
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// TODO ArrayBuffer ?
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var w = new Int32Array(16); |
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for (i = 0; i < paddedLength;) { |
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for (j = 0; j < 16; ++j, i += 4) |
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w[j] = padded[i] | (padded[i + 1] << 8) | (padded[i + 2] << 16) | (padded[i + 3] << 24); |
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var a = h0, b = h1, c = h2, d = h3, f, g; |
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for (j = 0; j < 64; ++j) { |
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if (j < 16) { |
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f = (b & c) | ((~b) & d); |
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g = j; |
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} else if (j < 32) { |
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f = (d & b) | ((~d) & c); |
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g = (5 * j + 1) & 15; |
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} else if (j < 48) { |
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f = b ^ c ^ d; |
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g = (3 * j + 5) & 15; |
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} else { |
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f = c ^ (b | (~d)); |
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g = (7 * j) & 15; |
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} |
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var tmp = d, rotateArg = (a + f + k[j] + w[g]) | 0, rotate = r[j]; |
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d = c; |
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c = b; |
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b = (b + ((rotateArg << rotate) | (rotateArg >>> (32 - rotate)))) | 0; |
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a = tmp; |
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} |
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h0 = (h0 + a) | 0; |
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h1 = (h1 + b) | 0; |
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h2 = (h2 + c) | 0; |
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h3 = (h3 + d) | 0; |
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} |
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return new Uint8Array([ |
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h0 & 0xFF, (h0 >> 8) & 0xFF, (h0 >> 16) & 0xFF, (h0 >>> 24) & 0xFF, |
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h1 & 0xFF, (h1 >> 8) & 0xFF, (h1 >> 16) & 0xFF, (h1 >>> 24) & 0xFF, |
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h2 & 0xFF, (h2 >> 8) & 0xFF, (h2 >> 16) & 0xFF, (h2 >>> 24) & 0xFF, |
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h3 & 0xFF, (h3 >> 8) & 0xFF, (h3 >> 16) & 0xFF, (h3 >>> 24) & 0xFF |
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]); |
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} |
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return hash; |
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})(); |
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var CipherTransform = (function() { |
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function constructor(stringCipherConstructor, streamCipherConstructor) { |
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this.stringCipherConstructor = stringCipherConstructor; |
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this.streamCipherConstructor = streamCipherConstructor; |
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} |
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constructor.prototype = { |
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createStream: function (stream) { |
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var cipher = new streamCipherConstructor(); |
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return new DecryptStream(stream, function(data) { |
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return cipher.encryptBlock(data); |
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}); |
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}, |
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decryptString: function(s) { |
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var cipher = new stringCipherConstructor(); |
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var data = string2bytes(s); |
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data = cipher.encryptBlock(data); |
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return bytes2string(data); |
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} |
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}; |
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return constructor; |
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})(); |
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var CipherTransformFactory = (function() { |
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function prepareKeyData(fileId, password, ownerPassword, userPassword, flags, revision, keyLength) { |
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const defaultPasswordBytes = new Uint8Array([ |
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0x28, 0xBF, 0x4E, 0x5E, 0x4E, 0x75, 0x8A, 0x41, 0x64, 0x00, 0x4E, 0x56, 0xFF, 0xFA, 0x01, 0x08, |
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0x2E, 0x2E, 0x00, 0xB6, 0xD0, 0x68, 0x3E, 0x80, 0x2F, 0x0C, 0xA9, 0xFE, 0x64, 0x53, 0x69, 0x7A]); |
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var hashData = new Uint8Array(88), i = 0, j, n; |
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if (password) { |
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n = Math.min(32, password.length); |
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for (; i < n; ++i) |
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hashData[i] = password[i]; |
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} |
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j = 0; |
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while (i < 32) { |
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hashData[i++] = defaultPasswordBytes[j++]; |
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} |
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// as now the padded password in the hashData[0..i]
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for (j = 0, n = ownerPassword.length; j < n; ++j) |
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hashData[i++] = ownerPassword[j]; |
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hashData[i++] = flags & 0xFF; |
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hashData[i++] = (flags >> 8) & 0xFF; |
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hashData[i++] = (flags >> 16) & 0xFF; |
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hashData[i++] = (flags >>> 24) & 0xFF; |
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for (j = 0, n = fileId.length; j < n; ++j) |
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hashData[i++] = fileId[j]; |
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// TODO rev 4, if metadata is not encrypted pass 0xFFFFFF also
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var hash = md5(hashData, 0, i); |
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var keyLengthInBytes = keyLength >> 3; |
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if (revision >= 3) { |
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for (j = 0; j < 50; ++j) { |
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hash = md5(hash, 0, keyLengthInBytes); |
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} |
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} |
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var encryptionKey = hash.subarray(0, keyLengthInBytes); |
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var cipher, checkData; |
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if (revision >= 3) { |
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// padded password in hashData, we can use this array for user password check
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i = 32; |
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for(j = 0, n = fileId.length; j < n; ++j) |
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hashData[i++] = fileId[j]; |
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cipher = new ARCFourCipher(encryptionKey); |
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var checkData = cipher.encryptBlock(md5(hashData, 0, i)); |
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n = encryptionKey.length; |
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var derrivedKey = new Uint8Array(n), k; |
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for (j = 1; j <= 19; ++j) { |
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for (k = 0; k < n; ++k) |
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derrivedKey[k] = encryptionKey[k] ^ j; |
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cipher = new ARCFourCipher(derrivedKey); |
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checkData = cipher.encryptBlock(checkData); |
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} |
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} else { |
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cipher = new ARCFourCipher(encryptionKey); |
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checkData = cipher.encryptBlock(hashData.subarray(0, 32)); |
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} |
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for (j = 0, n = checkData.length; j < n; ++j) { |
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if (userPassword[j] != checkData[j]) |
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error("incorrect password"); |
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} |
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return encryptionKey; |
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} |
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function constructor(dict, fileId, password) { |
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var filter = dict.get("Filter"); |
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if (!IsName(filter) || filter.name != "Standard") |
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error("unknown encryption method"); |
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this.dict = dict; |
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var algorithm = dict.get("V"); |
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if (!IsInt(algorithm) || |
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(algorithm != 1 && algorithm != 2)) |
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error("unsupported encryption algorithm"); |
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// TODO support algorithm 4
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var keyLength = dict.get("Length") || 40; |
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if (!IsInt(keyLength) || |
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keyLength < 40 || (keyLength % 8) != 0) |
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error("invalid key length"); |
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// prepare keys
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var ownerPassword = stringToBytes(dict.get("O")); |
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var userPassword = stringToBytes(dict.get("U")); |
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var flags = dict.get("P"); |
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var revision = dict.get("R"); |
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var fileIdBytes = stringToBytes(fileId); |
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var passwordBytes; |
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if (password) |
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passwordBytes = stringToBytes(password); |
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this.encryptionKey = prepareKeyData(fileIdBytes, passwordBytes, |
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ownerPassword, userPassword, flags, revision, keyLength); |
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} |
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constructor.prototype = { |
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createCipherTransform: function(num, gen) { |
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var encryptionKey = this.encryptionKey; |
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var key = new Uint8Array(encryptionKey.length + 5), i, j, n; |
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for (j = 0, n = encryptionKey.length; j < n; ++j) |
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key[j] = encryptionKey[j]; |
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key[i++] = num & 0xFF; |
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key[i++] = (num >> 8) & 0xFF; |
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key[i++] = (num >> 16) & 0xFF; |
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key[i++] = gen & 0xFF; |
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key[i++] = (gen >> 8) & 0xFF; |
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var hash = md5(key, 0, i); |
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key = hash.subarray(0, Math.min(key.length, 16)); |
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var cipherConstructor = function() { |
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return new ARCFourCipher(key); |
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}; |
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return new CipherTransform(cipherConstructor, cipherConstructor); |
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} |
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}; |
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return constructor; |
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})(); |
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