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define(["../base64", "./_base"], |
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function(base64, crypto){ |
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// Sbox is pre-computed multiplicative inverse in GF(2^8) used in SubBytes and KeyExpansion [5.1.1] |
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var Sbox = [0x63,0x7c,0x77,0x7b,0xf2,0x6b,0x6f,0xc5,0x30,0x01,0x67,0x2b,0xfe,0xd7,0xab,0x76, |
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0xca,0x82,0xc9,0x7d,0xfa,0x59,0x47,0xf0,0xad,0xd4,0xa2,0xaf,0x9c,0xa4,0x72,0xc0, |
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0xb7,0xfd,0x93,0x26,0x36,0x3f,0xf7,0xcc,0x34,0xa5,0xe5,0xf1,0x71,0xd8,0x31,0x15, |
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0x04,0xc7,0x23,0xc3,0x18,0x96,0x05,0x9a,0x07,0x12,0x80,0xe2,0xeb,0x27,0xb2,0x75, |
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0x09,0x83,0x2c,0x1a,0x1b,0x6e,0x5a,0xa0,0x52,0x3b,0xd6,0xb3,0x29,0xe3,0x2f,0x84, |
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0x53,0xd1,0x00,0xed,0x20,0xfc,0xb1,0x5b,0x6a,0xcb,0xbe,0x39,0x4a,0x4c,0x58,0xcf, |
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0xd0,0xef,0xaa,0xfb,0x43,0x4d,0x33,0x85,0x45,0xf9,0x02,0x7f,0x50,0x3c,0x9f,0xa8, |
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0x51,0xa3,0x40,0x8f,0x92,0x9d,0x38,0xf5,0xbc,0xb6,0xda,0x21,0x10,0xff,0xf3,0xd2, |
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0xcd,0x0c,0x13,0xec,0x5f,0x97,0x44,0x17,0xc4,0xa7,0x7e,0x3d,0x64,0x5d,0x19,0x73, |
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0x60,0x81,0x4f,0xdc,0x22,0x2a,0x90,0x88,0x46,0xee,0xb8,0x14,0xde,0x5e,0x0b,0xdb, |
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0xe0,0x32,0x3a,0x0a,0x49,0x06,0x24,0x5c,0xc2,0xd3,0xac,0x62,0x91,0x95,0xe4,0x79, |
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0xe7,0xc8,0x37,0x6d,0x8d,0xd5,0x4e,0xa9,0x6c,0x56,0xf4,0xea,0x65,0x7a,0xae,0x08, |
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0xba,0x78,0x25,0x2e,0x1c,0xa6,0xb4,0xc6,0xe8,0xdd,0x74,0x1f,0x4b,0xbd,0x8b,0x8a, |
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0x70,0x3e,0xb5,0x66,0x48,0x03,0xf6,0x0e,0x61,0x35,0x57,0xb9,0x86,0xc1,0x1d,0x9e, |
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0xe1,0xf8,0x98,0x11,0x69,0xd9,0x8e,0x94,0x9b,0x1e,0x87,0xe9,0xce,0x55,0x28,0xdf, |
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0x8c,0xa1,0x89,0x0d,0xbf,0xe6,0x42,0x68,0x41,0x99,0x2d,0x0f,0xb0,0x54,0xbb,0x16]; |
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// Rcon is Round Constant used for the Key Expansion [1st col is 2^(r-1) in GF(2^8)] [5.2] |
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var Rcon = [ [0x00, 0x00, 0x00, 0x00], |
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[0x01, 0x00, 0x00, 0x00], |
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[0x02, 0x00, 0x00, 0x00], |
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[0x04, 0x00, 0x00, 0x00], |
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[0x08, 0x00, 0x00, 0x00], |
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[0x10, 0x00, 0x00, 0x00], |
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[0x20, 0x00, 0x00, 0x00], |
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[0x40, 0x00, 0x00, 0x00], |
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[0x80, 0x00, 0x00, 0x00], |
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[0x1b, 0x00, 0x00, 0x00], |
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[0x36, 0x00, 0x00, 0x00] ]; |
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/* |
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* AES Cipher function: encrypt 'input' with Rijndael algorithm |
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* |
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* takes byte-array 'input' (16 bytes) |
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* 2D byte-array key schedule 'w' (Nr+1 x Nb bytes) |
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* |
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* applies Nr rounds (10/12/14) using key schedule w for 'add round key' stage |
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* |
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* returns byte-array encrypted value (16 bytes) |
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*/ |
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function Cipher(input, w) { // main Cipher function [<EFBFBD><EFBFBD>5.1] |
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var Nb = 4; // block size (in words): no of columns in state (fixed at 4 for AES) |
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var Nr = w.length/Nb - 1; // no of rounds: 10/12/14 for 128/192/256-bit keys |
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var state = [[],[],[],[]]; // initialise 4xNb byte-array 'state' with input [3.4] |
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for (var i=0; i<4*Nb; i++) state[i%4][Math.floor(i/4)] = input[i]; |
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state = AddRoundKey(state, w, 0, Nb); |
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for (var round=1; round<Nr; round++) { |
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state = SubBytes(state, Nb); |
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state = ShiftRows(state, Nb); |
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state = MixColumns(state, Nb); |
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state = AddRoundKey(state, w, round, Nb); |
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} |
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state = SubBytes(state, Nb); |
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state = ShiftRows(state, Nb); |
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state = AddRoundKey(state, w, Nr, Nb); |
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var output = new Array(4*Nb); // convert state to 1-d array before returning [3.4] |
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for (var i=0; i<4*Nb; i++) output[i] = state[i%4][Math.floor(i/4)]; |
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return output; |
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} |
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function SubBytes(s, Nb) { // apply SBox to state S [5.1.1] |
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for (var r=0; r<4; r++) { |
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for (var c=0; c<Nb; c++) s[r][c] = Sbox[s[r][c]]; |
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} |
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return s; |
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} |
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function ShiftRows(s, Nb) { // shift row r of state S left by r bytes [5.1.2] |
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var t = new Array(4); |
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for (var r=1; r<4; r++) { |
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for (var c=0; c<4; c++) t[c] = s[r][(c+r)%Nb]; // shift into temp copy |
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for (var c=0; c<4; c++) s[r][c] = t[c]; // and copy back |
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} // note that this will work for Nb=4,5,6, but not 7,8 (always 4 for AES): |
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return s; // see fp.gladman.plus.com/cryptography_technology/rijndael/aes.spec.311.pdf |
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} |
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function MixColumns(s, Nb) { // combine bytes of each col of state S [5.1.3] |
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for (var c=0; c<4; c++) { |
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var a = new Array(4); // 'a' is a copy of the current column from 's' |
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var b = new Array(4); // 'b' is a<EFBFBD>ށ{02} in GF(2^8) |
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for (var i=0; i<4; i++) { |
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a[i] = s[i][c]; |
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b[i] = s[i][c]&0x80 ? s[i][c]<<1 ^ 0x011b : s[i][c]<<1; |
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} |
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// a[n] ^ b[n] is a<EFBFBD>ށ{03} in GF(2^8) |
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s[0][c] = b[0] ^ a[1] ^ b[1] ^ a[2] ^ a[3]; // 2*a0 + 3*a1 + a2 + a3 |
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s[1][c] = a[0] ^ b[1] ^ a[2] ^ b[2] ^ a[3]; // a0 * 2*a1 + 3*a2 + a3 |
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s[2][c] = a[0] ^ a[1] ^ b[2] ^ a[3] ^ b[3]; // a0 + a1 + 2*a2 + 3*a3 |
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s[3][c] = a[0] ^ b[0] ^ a[1] ^ a[2] ^ b[3]; // 3*a0 + a1 + a2 + 2*a3 |
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} |
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return s; |
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} |
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function AddRoundKey(state, w, rnd, Nb) { // xor Round Key into state S [5.1.4] |
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for (var r=0; r<4; r++) { |
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for (var c=0; c<Nb; c++) state[r][c] ^= w[rnd*4+c][r]; |
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} |
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return state; |
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} |
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function KeyExpansion(key) { // generate Key Schedule (byte-array Nr+1 x Nb) from Key [5.2] |
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var Nb = 4; // block size (in words): no of columns in state (fixed at 4 for AES) |
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var Nk = key.length/4 // key length (in words): 4/6/8 for 128/192/256-bit keys |
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var Nr = Nk + 6; // no of rounds: 10/12/14 for 128/192/256-bit keys |
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var w = new Array(Nb*(Nr+1)); |
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var temp = new Array(4); |
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for (var i=0; i<Nk; i++) { |
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var r = [key[4*i], key[4*i+1], key[4*i+2], key[4*i+3]]; |
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w[i] = r; |
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} |
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for (var i=Nk; i<(Nb*(Nr+1)); i++) { |
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w[i] = new Array(4); |
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for (var t=0; t<4; t++) temp[t] = w[i-1][t]; |
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if (i % Nk == 0) { |
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temp = SubWord(RotWord(temp)); |
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for (var t=0; t<4; t++) temp[t] ^= Rcon[i/Nk][t]; |
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} else if (Nk > 6 && i%Nk == 4) { |
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temp = SubWord(temp); |
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} |
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for (var t=0; t<4; t++) w[i][t] = w[i-Nk][t] ^ temp[t]; |
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} |
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return w; |
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} |
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function SubWord(w) { // apply SBox to 4-byte word w |
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for (var i=0; i<4; i++) w[i] = Sbox[w[i]]; |
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return w; |
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} |
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function RotWord(w) { // rotate 4-byte word w left by one byte |
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w[4] = w[0]; |
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for (var i=0; i<4; i++) w[i] = w[i+1]; |
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return w; |
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} |
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/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */ |
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/* |
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* Use AES to encrypt 'plaintext' with 'password' using 'nBits' key, in 'Counter' mode of operation |
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* - see http://csrc.nist.gov/publications/nistpubs/800-38a/sp800-38a.pdf |
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* for each block |
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* - outputblock = cipher(counter, key) |
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* - cipherblock = plaintext xor outputblock |
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*/ |
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function AESEncryptCtr(plaintext, password, nBits) { |
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if (!(nBits==128 || nBits==192 || nBits==256)) return ''; // standard allows 128/192/256 bit keys |
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// for this example script, generate the key by applying Cipher to 1st 16/24/32 chars of password; |
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// for real-world applications, a more secure approach would be to hash the password e.g. with SHA-1 |
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var nBytes = nBits/8; // no bytes in key |
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var pwBytes = new Array(nBytes); |
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for (var i=0; i<nBytes; i++) pwBytes[i] = password.charCodeAt(i) & 0xff; |
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var key = Cipher(pwBytes, KeyExpansion(pwBytes)); |
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key = key.concat(key.slice(0, nBytes-16)); // key is now 16/24/32 bytes long |
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// initialise counter block (NIST SP800-38A B.2): millisecond time-stamp for nonce in 1st 8 bytes, |
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// block counter in 2nd 8 bytes |
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var blockSize = 16; // block size fixed at 16 bytes / 128 bits (Nb=4) for AES |
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var counterBlock = new Array(blockSize); // block size fixed at 16 bytes / 128 bits (Nb=4) for AES |
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var nonce = (new Date()).getTime(); // milliseconds since 1-Jan-1970 |
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// encode nonce in two stages to cater for JavaScript 32-bit limit on bitwise ops |
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for (var i=0; i<4; i++) counterBlock[i] = (nonce >>> i*8) & 0xff; |
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for (var i=0; i<4; i++) counterBlock[i+4] = (nonce/0x100000000 >>> i*8) & 0xff; |
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// generate key schedule - an expansion of the key into distinct Key Rounds for each round |
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var keySchedule = KeyExpansion(key); |
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var blockCount = Math.ceil(plaintext.length/blockSize); |
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var ciphertext = new Array(blockCount); // ciphertext as array of strings |
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for (var b=0; b<blockCount; b++) { |
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// set counter (block #) in last 8 bytes of counter block (leaving nonce in 1st 8 bytes) |
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// again done in two stages for 32-bit ops |
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for (var c=0; c<4; c++) counterBlock[15-c] = (b >>> c*8) & 0xff; |
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for (var c=0; c<4; c++) counterBlock[15-c-4] = (b/0x100000000 >>> c*8) |
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var cipherCntr = Cipher(counterBlock, keySchedule); // -- encrypt counter block -- |
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// calculate length of final block: |
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var blockLength = b<blockCount-1 ? blockSize : (plaintext.length-1)%blockSize+1; |
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var ct = ''; |
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for (var i=0; i<blockLength; i++) { // -- xor plaintext with ciphered counter byte-by-byte -- |
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var plaintextByte = plaintext.charCodeAt(b*blockSize+i); |
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var cipherByte = plaintextByte ^ cipherCntr[i]; |
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//ct += String.fromCharCode(cipherByte); |
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ct += ((cipherByte < 16) ? "0" : "") + cipherByte.toString(16); |
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} |
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// ct is now ciphertext for this block |
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ciphertext[b] = ct; // escCtrlChars(ct); // escape troublesome characters in ciphertext |
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} |
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// convert the nonce to a string to go on the front of the ciphertext |
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var ctrTxt = ''; |
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for (var i=0; i<8; i++) ctrTxt += ((counterBlock[i] < 16) ? "0" : "") + counterBlock[i].toString(16); //String.fromCharCode(counterBlock[i]); |
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//ctrTxt = escCtrlChars(ctrTxt); |
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// use '-' to separate blocks, use Array.join to concatenate arrays of strings for efficiency |
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return ctrTxt + ' ' + ciphertext.join(' '); |
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} |
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function stringToHex(s){ |
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var ret = []; |
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s.replace(/(..)/g, function(str){ |
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ret.push(parseInt(str, 16)); |
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}); |
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return ret; |
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} |
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/* |
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* Use AES to decrypt 'ciphertext' with 'password' using 'nBits' key, in Counter mode of operation |
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* |
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* for each block |
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* - outputblock = cipher(counter, key) |
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* - cipherblock = plaintext xor outputblock |
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*/ |
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function AESDecryptCtr(ciphertext, password, nBits) { |
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if (!(nBits==128 || nBits==192 || nBits==256)) return ''; // standard allows 128/192/256 bit keys |
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var nBytes = nBits/8; // no bytes in key |
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var pwBytes = new Array(nBytes); |
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for (var i=0; i<nBytes; i++) pwBytes[i] = password.charCodeAt(i) & 0xff; |
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var pwKeySchedule = KeyExpansion(pwBytes); |
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var key = Cipher(pwBytes, pwKeySchedule); |
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key = key.concat(key.slice(0, nBytes-16)); // key is now 16/24/32 bytes long |
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var keySchedule = KeyExpansion(key); |
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ciphertext = ciphertext.split(' '); // split ciphertext into array of block-length strings |
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// recover nonce from 1st element of ciphertext |
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var blockSize = 16; // block size fixed at 16 bytes / 128 bits (Nb=4) for AES |
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var counterBlock = new Array(blockSize); |
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var ctrTxt = ciphertext[0]; //unescCtrlChars(ciphertext[0]); |
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counterBlock = stringToHex(ctrTxt); |
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var plaintext = new Array(ciphertext.length-1); |
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for (var b=1; b<ciphertext.length; b++) { |
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// set counter (block #) in last 8 bytes of counter block (leaving nonce in 1st 8 bytes) |
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for (var c=0; c<4; c++) counterBlock[15-c] = ((b-1) >>> c*8) & 0xff; |
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for (var c=0; c<4; c++) counterBlock[15-c-4] = ((b/0x100000000-1) >>> c*8) & 0xff; |
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var cipherCntr = Cipher(counterBlock, keySchedule); // encrypt counter block |
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//ciphertext[b] = ciphertext[b]; //unescCtrlChars(ciphertext[b]); |
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var pt = ''; |
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var tmp = stringToHex(ciphertext[b]); |
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for (var i=0; i<tmp.length; i++) { |
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// -- xor plaintext with ciphered counter byte-by-byte -- |
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var ciphertextByte = ciphertext[b].charCodeAt(i); |
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var plaintextByte = tmp[i] ^ cipherCntr[i]; |
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pt += String.fromCharCode(plaintextByte); |
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} |
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// pt is now plaintext for this block |
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plaintext[b-1] = pt; // b-1 'cos no initial nonce block in plaintext |
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} |
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return plaintext.join(''); |
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} |
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/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */ |
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function escCtrlChars(str) { // escape control chars which might cause problems handling ciphertext |
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return str.replace(/[\0\t\n\v\f\r\xa0!-]/g, function(c) { return '!' + c.charCodeAt(0) + '!'; }); |
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} // \xa0 to cater for bug in Firefox; include '-' to leave it free for use as a block marker |
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function unescCtrlChars(str) { // unescape potentially problematic control characters |
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return str.replace(/!\d\d?\d?!/g, function(c) { return String.fromCharCode(c.slice(1,-1)); }); |
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} |
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/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */ |
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crypto.SimpleAES = new (function(){ |
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// summary: |
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// SimpleAES, ported from dojox.sql, and done without the need for |
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// a Google Gears worker pool. |
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// description: |
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// Taken from http://www.movable-type.co.uk/scripts/aes.html by |
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// Chris Veness (CLA signed); adapted for Dojo by Brad Neuberg |
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// (bkn3 AT columbia.edu) and moved to DojoX crypto by Tom Trenka |
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// (ttrenka AT gmail.com). |
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// |
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// A few notes: |
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// 1) This algorithm uses a customized version of CBC mode by creating |
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// a nonce, using it as an initialization vector, and storing the |
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// IV as the first portion of the encrypted text. Because of this, it |
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// is HIGHLY PROBABLE that it will NOT be usable by other AES implementations. |
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// 2) All encoding is done in hex format; other encoding formats (such |
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// as base 64) are not supported. |
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// 3) The bit depth of the key is hardcoded at 256, despite the ability |
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// of the code to handle all three recommended bit depths. |
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// 4) The passed key will be padded (as opposed to enforcing a strict |
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// length) with null bytes. |
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this.encrypt = function(/* String */plaintext, /* String */key){ |
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// summary: |
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// Encrypt the passed plaintext using the key, with a |
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// hardcoded bit depth of 256. |
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return AESEncryptCtr(plaintext, key, 256); // String |
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}; |
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this.decrypt = function(/* String */ciphertext, /* String */key){ |
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// summary: |
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// Decrypt the passed ciphertext using the key at a fixed |
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// bit depth of 256. |
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return AESDecryptCtr(ciphertext, key, 256); // String |
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}; |
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})(); |
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return crypto.SimpleAES; |
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});
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