| /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */ |
| |
| /* |
| * AES Cipher function: encrypt 'input' with Rijndael algorithm |
| * |
| * takes byte-array 'input' (16 bytes) |
| * 2D byte-array key schedule 'w' (Nr+1 x Nb bytes) |
| * |
| * applies Nr rounds (10/12/14) using key schedule w for 'add round key' stage |
| * |
| * returns byte-array encrypted value (16 bytes) |
| */ |
| function Cipher(input, w) { // main Cipher function [§5.1] |
| var Nb = 4; // block size (in words): no of columns in state (fixed at 4 for AES) |
| var Nr = w.length/Nb - 1; // no of rounds: 10/12/14 for 128/192/256-bit keys |
| |
| var state = [[],[],[],[]]; // initialise 4xNb byte-array 'state' with input [§3.4] |
| for (var i=0; i<4*Nb; i++) state[i%4][Math.floor(i/4)] = input[i]; |
| |
| state = AddRoundKey(state, w, 0, Nb); |
| |
| for (var round=1; round<Nr; round++) { |
| state = SubBytes(state, Nb); |
| state = ShiftRows(state, Nb); |
| state = MixColumns(state, Nb); |
| state = AddRoundKey(state, w, round, Nb); |
| } |
| |
| state = SubBytes(state, Nb); |
| state = ShiftRows(state, Nb); |
| state = AddRoundKey(state, w, Nr, Nb); |
| |
| var output = new Array(4*Nb); // convert state to 1-d array before returning [§3.4] |
| for (var i=0; i<4*Nb; i++) output[i] = state[i%4][Math.floor(i/4)]; |
| return output; |
| } |
| |
| |
| function SubBytes(s, Nb) { // apply SBox to state S [§5.1.1] |
| for (var r=0; r<4; r++) { |
| for (var c=0; c<Nb; c++) s[r][c] = Sbox[s[r][c]]; |
| } |
| return s; |
| } |
| |
| |
| function ShiftRows(s, Nb) { // shift row r of state S left by r bytes [§5.1.2] |
| var t = new Array(4); |
| for (var r=1; r<4; r++) { |
| for (var c=0; c<4; c++) t[c] = s[r][(c+r)%Nb]; // shift into temp copy |
| for (var c=0; c<4; c++) s[r][c] = t[c]; // and copy back |
| } // note that this will work for Nb=4,5,6, but not 7,8 (always 4 for AES): |
| return s; // see fp.gladman.plus.com/cryptography_technology/rijndael/aes.spec.311.pdf |
| } |
| |
| |
| function MixColumns(s, Nb) { // combine bytes of each col of state S [§5.1.3] |
| for (var c=0; c<4; c++) { |
| var a = new Array(4); // 'a' is a copy of the current column from 's' |
| var b = new Array(4); // 'b' is a•{02} in GF(2^8) |
| for (var i=0; i<4; i++) { |
| a[i] = s[i][c]; |
| b[i] = s[i][c]&0x80 ? s[i][c]<<1 ^ 0x011b : s[i][c]<<1; |
| } |
| // a[n] ^ b[n] is a•{03} in GF(2^8) |
| s[0][c] = b[0] ^ a[1] ^ b[1] ^ a[2] ^ a[3]; // 2*a0 + 3*a1 + a2 + a3 |
| s[1][c] = a[0] ^ b[1] ^ a[2] ^ b[2] ^ a[3]; // a0 * 2*a1 + 3*a2 + a3 |
| s[2][c] = a[0] ^ a[1] ^ b[2] ^ a[3] ^ b[3]; // a0 + a1 + 2*a2 + 3*a3 |
| s[3][c] = a[0] ^ b[0] ^ a[1] ^ a[2] ^ b[3]; // 3*a0 + a1 + a2 + 2*a3 |
| } |
| return s; |
| } |
| |
| |
| function AddRoundKey(state, w, rnd, Nb) { // xor Round Key into state S [§5.1.4] |
| for (var r=0; r<4; r++) { |
| for (var c=0; c<Nb; c++) state[r][c] ^= w[rnd*4+c][r]; |
| } |
| return state; |
| } |
| |
| |
| function KeyExpansion(key) { // generate Key Schedule (byte-array Nr+1 x Nb) from Key [§5.2] |
| var Nb = 4; // block size (in words): no of columns in state (fixed at 4 for AES) |
| var Nk = key.length/4 // key length (in words): 4/6/8 for 128/192/256-bit keys |
| var Nr = Nk + 6; // no of rounds: 10/12/14 for 128/192/256-bit keys |
| |
| var w = new Array(Nb*(Nr+1)); |
| var temp = new Array(4); |
| |
| for (var i=0; i<Nk; i++) { |
| var r = [key[4*i], key[4*i+1], key[4*i+2], key[4*i+3]]; |
| w[i] = r; |
| } |
| |
| for (var i=Nk; i<(Nb*(Nr+1)); i++) { |
| w[i] = new Array(4); |
| for (var t=0; t<4; t++) temp[t] = w[i-1][t]; |
| if (i % Nk == 0) { |
| temp = SubWord(RotWord(temp)); |
| for (var t=0; t<4; t++) temp[t] ^= Rcon[i/Nk][t]; |
| } else if (Nk > 6 && i%Nk == 4) { |
| temp = SubWord(temp); |
| } |
| for (var t=0; t<4; t++) w[i][t] = w[i-Nk][t] ^ temp[t]; |
| } |
| |
| return w; |
| } |
| |
| function SubWord(w) { // apply SBox to 4-byte word w |
| for (var i=0; i<4; i++) w[i] = Sbox[w[i]]; |
| return w; |
| } |
| |
| function RotWord(w) { // rotate 4-byte word w left by one byte |
| w[4] = w[0]; |
| for (var i=0; i<4; i++) w[i] = w[i+1]; |
| return w; |
| } |
| |
| |
| // Sbox is pre-computed multiplicative inverse in GF(2^8) used in SubBytes and KeyExpansion [§5.1.1] |
| var Sbox = [0x63,0x7c,0x77,0x7b,0xf2,0x6b,0x6f,0xc5,0x30,0x01,0x67,0x2b,0xfe,0xd7,0xab,0x76, |
| 0xca,0x82,0xc9,0x7d,0xfa,0x59,0x47,0xf0,0xad,0xd4,0xa2,0xaf,0x9c,0xa4,0x72,0xc0, |
| 0xb7,0xfd,0x93,0x26,0x36,0x3f,0xf7,0xcc,0x34,0xa5,0xe5,0xf1,0x71,0xd8,0x31,0x15, |
| 0x04,0xc7,0x23,0xc3,0x18,0x96,0x05,0x9a,0x07,0x12,0x80,0xe2,0xeb,0x27,0xb2,0x75, |
| 0x09,0x83,0x2c,0x1a,0x1b,0x6e,0x5a,0xa0,0x52,0x3b,0xd6,0xb3,0x29,0xe3,0x2f,0x84, |
| 0x53,0xd1,0x00,0xed,0x20,0xfc,0xb1,0x5b,0x6a,0xcb,0xbe,0x39,0x4a,0x4c,0x58,0xcf, |
| 0xd0,0xef,0xaa,0xfb,0x43,0x4d,0x33,0x85,0x45,0xf9,0x02,0x7f,0x50,0x3c,0x9f,0xa8, |
| 0x51,0xa3,0x40,0x8f,0x92,0x9d,0x38,0xf5,0xbc,0xb6,0xda,0x21,0x10,0xff,0xf3,0xd2, |
| 0xcd,0x0c,0x13,0xec,0x5f,0x97,0x44,0x17,0xc4,0xa7,0x7e,0x3d,0x64,0x5d,0x19,0x73, |
| 0x60,0x81,0x4f,0xdc,0x22,0x2a,0x90,0x88,0x46,0xee,0xb8,0x14,0xde,0x5e,0x0b,0xdb, |
| 0xe0,0x32,0x3a,0x0a,0x49,0x06,0x24,0x5c,0xc2,0xd3,0xac,0x62,0x91,0x95,0xe4,0x79, |
| 0xe7,0xc8,0x37,0x6d,0x8d,0xd5,0x4e,0xa9,0x6c,0x56,0xf4,0xea,0x65,0x7a,0xae,0x08, |
| 0xba,0x78,0x25,0x2e,0x1c,0xa6,0xb4,0xc6,0xe8,0xdd,0x74,0x1f,0x4b,0xbd,0x8b,0x8a, |
| 0x70,0x3e,0xb5,0x66,0x48,0x03,0xf6,0x0e,0x61,0x35,0x57,0xb9,0x86,0xc1,0x1d,0x9e, |
| 0xe1,0xf8,0x98,0x11,0x69,0xd9,0x8e,0x94,0x9b,0x1e,0x87,0xe9,0xce,0x55,0x28,0xdf, |
| 0x8c,0xa1,0x89,0x0d,0xbf,0xe6,0x42,0x68,0x41,0x99,0x2d,0x0f,0xb0,0x54,0xbb,0x16]; |
| |
| // Rcon is Round Constant used for the Key Expansion [1st col is 2^(r-1) in GF(2^8)] [§5.2] |
| var Rcon = [ [0x00, 0x00, 0x00, 0x00], |
| [0x01, 0x00, 0x00, 0x00], |
| [0x02, 0x00, 0x00, 0x00], |
| [0x04, 0x00, 0x00, 0x00], |
| [0x08, 0x00, 0x00, 0x00], |
| [0x10, 0x00, 0x00, 0x00], |
| [0x20, 0x00, 0x00, 0x00], |
| [0x40, 0x00, 0x00, 0x00], |
| [0x80, 0x00, 0x00, 0x00], |
| [0x1b, 0x00, 0x00, 0x00], |
| [0x36, 0x00, 0x00, 0x00] ]; |
| |
| |
| /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */ |
| |
| /* |
| * Use AES to encrypt 'plaintext' with 'password' using 'nBits' key, in 'Counter' mode of operation |
| * - see http://csrc.nist.gov/publications/nistpubs/800-38a/sp800-38a.pdf |
| * for each block |
| * - outputblock = cipher(counter, key) |
| * - cipherblock = plaintext xor outputblock |
| */ |
| function AESEncryptCtr(plaintext, password, nBits) { |
| if (!(nBits==128 || nBits==192 || nBits==256)) return ''; // standard allows 128/192/256 bit keys |
| |
| // for this example script, generate the key by applying Cipher to 1st 16/24/32 chars of password; |
| // for real-world applications, a more secure approach would be to hash the password e.g. with SHA-1 |
| var nBytes = nBits/8; // no bytes in key |
| var pwBytes = new Array(nBytes); |
| for (var i=0; i<nBytes; i++) pwBytes[i] = password.charCodeAt(i) & 0xff; |
| var key = Cipher(pwBytes, KeyExpansion(pwBytes)); |
| key = key.concat(key.slice(0, nBytes-16)); // key is now 16/24/32 bytes long |
| |
| // initialise counter block (NIST SP800-38A §B.2): millisecond time-stamp for nonce in 1st 8 bytes, |
| // block counter in 2nd 8 bytes |
| var blockSize = 16; // block size fixed at 16 bytes / 128 bits (Nb=4) for AES |
| var counterBlock = new Array(blockSize); // block size fixed at 16 bytes / 128 bits (Nb=4) for AES |
| var nonce = (new Date()).getTime(); // milliseconds since 1-Jan-1970 |
| |
| // encode nonce in two stages to cater for JavaScript 32-bit limit on bitwise ops |
| for (var i=0; i<4; i++) counterBlock[i] = (nonce >>> i*8) & 0xff; |
| for (var i=0; i<4; i++) counterBlock[i+4] = (nonce/0x100000000 >>> i*8) & 0xff; |
| |
| // generate key schedule - an expansion of the key into distinct Key Rounds for each round |
| var keySchedule = KeyExpansion(key); |
| |
| var blockCount = Math.ceil(plaintext.length/blockSize); |
| var ciphertext = new Array(blockCount); // ciphertext as array of strings |
| |
| for (var b=0; b<blockCount; b++) { |
| // set counter (block #) in last 8 bytes of counter block (leaving nonce in 1st 8 bytes) |
| // again done in two stages for 32-bit ops |
| for (var c=0; c<4; c++) counterBlock[15-c] = (b >>> c*8) & 0xff; |
| for (var c=0; c<4; c++) counterBlock[15-c-4] = (b/0x100000000 >>> c*8) |
| |
| var cipherCntr = Cipher(counterBlock, keySchedule); // -- encrypt counter block -- |
| |
| // calculate length of final block: |
| var blockLength = b<blockCount-1 ? blockSize : (plaintext.length-1)%blockSize+1; |
| |
| var ct = ''; |
| for (var i=0; i<blockLength; i++) { // -- xor plaintext with ciphered counter byte-by-byte -- |
| var plaintextByte = plaintext.charCodeAt(b*blockSize+i); |
| var cipherByte = plaintextByte ^ cipherCntr[i]; |
| ct += String.fromCharCode(cipherByte); |
| } |
| // ct is now ciphertext for this block |
| |
| ciphertext[b] = escCtrlChars(ct); // escape troublesome characters in ciphertext |
| } |
| |
| // convert the nonce to a string to go on the front of the ciphertext |
| var ctrTxt = ''; |
| for (var i=0; i<8; i++) ctrTxt += String.fromCharCode(counterBlock[i]); |
| ctrTxt = escCtrlChars(ctrTxt); |
| |
| // use '-' to separate blocks, use Array.join to concatenate arrays of strings for efficiency |
| return ctrTxt + '-' + ciphertext.join('-'); |
| } |
| |
| |
| /* |
| * Use AES to decrypt 'ciphertext' with 'password' using 'nBits' key, in Counter mode of operation |
| * |
| * for each block |
| * - outputblock = cipher(counter, key) |
| * - cipherblock = plaintext xor outputblock |
| */ |
| function AESDecryptCtr(ciphertext, password, nBits) { |
| if (!(nBits==128 || nBits==192 || nBits==256)) return ''; // standard allows 128/192/256 bit keys |
| |
| var nBytes = nBits/8; // no bytes in key |
| var pwBytes = new Array(nBytes); |
| for (var i=0; i<nBytes; i++) pwBytes[i] = password.charCodeAt(i) & 0xff; |
| var pwKeySchedule = KeyExpansion(pwBytes); |
| var key = Cipher(pwBytes, pwKeySchedule); |
| key = key.concat(key.slice(0, nBytes-16)); // key is now 16/24/32 bytes long |
| |
| var keySchedule = KeyExpansion(key); |
| |
| ciphertext = ciphertext.split('-'); // split ciphertext into array of block-length strings |
| |
| // recover nonce from 1st element of ciphertext |
| var blockSize = 16; // block size fixed at 16 bytes / 128 bits (Nb=4) for AES |
| var counterBlock = new Array(blockSize); |
| var ctrTxt = unescCtrlChars(ciphertext[0]); |
| for (var i=0; i<8; i++) counterBlock[i] = ctrTxt.charCodeAt(i); |
| |
| var plaintext = new Array(ciphertext.length-1); |
| |
| for (var b=1; b<ciphertext.length; b++) { |
| // set counter (block #) in last 8 bytes of counter block (leaving nonce in 1st 8 bytes) |
| for (var c=0; c<4; c++) counterBlock[15-c] = ((b-1) >>> c*8) & 0xff; |
| for (var c=0; c<4; c++) counterBlock[15-c-4] = ((b/0x100000000-1) >>> c*8) & 0xff; |
| |
| var cipherCntr = Cipher(counterBlock, keySchedule); // encrypt counter block |
| |
| ciphertext[b] = unescCtrlChars(ciphertext[b]); |
| |
| var pt = ''; |
| for (var i=0; i<ciphertext[b].length; i++) { |
| // -- xor plaintext with ciphered counter byte-by-byte -- |
| var ciphertextByte = ciphertext[b].charCodeAt(i); |
| var plaintextByte = ciphertextByte ^ cipherCntr[i]; |
| pt += String.fromCharCode(plaintextByte); |
| } |
| // pt is now plaintext for this block |
| |
| plaintext[b-1] = pt; // b-1 'cos no initial nonce block in plaintext |
| } |
| |
| return plaintext.join(''); |
| } |
| |
| /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */ |
| |
| function escCtrlChars(str) { // escape control chars which might cause problems handling ciphertext |
| return str.replace(/[\0\t\n\v\f\r\xa0'"!-]/g, function(c) { return '!' + c.charCodeAt(0) + '!'; }); |
| } // \xa0 to cater for bug in Firefox; include '-' to leave it free for use as a block marker |
| |
| function unescCtrlChars(str) { // unescape potentially problematic control characters |
| return str.replace(/!\d\d?\d?!/g, function(c) { return String.fromCharCode(c.slice(1,-1)); }); |
| } |
| /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */ |
| |
| /* |
| * if escCtrlChars()/unescCtrlChars() still gives problems, use encodeBase64()/decodeBase64() instead |
| */ |
| var b64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/="; |
| |
| function encodeBase64(str) { // http://tools.ietf.org/html/rfc4648 |
| var o1, o2, o3, h1, h2, h3, h4, bits, i=0, enc=''; |
| |
| str = encodeUTF8(str); // encode multi-byte chars into UTF-8 for byte-array |
| |
| do { // pack three octets into four hexets |
| o1 = str.charCodeAt(i++); |
| o2 = str.charCodeAt(i++); |
| o3 = str.charCodeAt(i++); |
| |
| bits = o1<<16 | o2<<8 | o3; |
| |
| h1 = bits>>18 & 0x3f; |
| h2 = bits>>12 & 0x3f; |
| h3 = bits>>6 & 0x3f; |
| h4 = bits & 0x3f; |
| |
| // end of string? index to '=' in b64 |
| if (isNaN(o3)) h4 = 64; |
| if (isNaN(o2)) h3 = 64; |
| |
| // use hexets to index into b64, and append result to encoded string |
| enc += b64.charAt(h1) + b64.charAt(h2) + b64.charAt(h3) + b64.charAt(h4); |
| } while (i < str.length); |
| |
| return enc; |
| } |
| |
| function decodeBase64(str) { |
| var o1, o2, o3, h1, h2, h3, h4, bits, i=0, enc=''; |
| |
| do { // unpack four hexets into three octets using index points in b64 |
| h1 = b64.indexOf(str.charAt(i++)); |
| h2 = b64.indexOf(str.charAt(i++)); |
| h3 = b64.indexOf(str.charAt(i++)); |
| h4 = b64.indexOf(str.charAt(i++)); |
| |
| bits = h1<<18 | h2<<12 | h3<<6 | h4; |
| |
| o1 = bits>>16 & 0xff; |
| o2 = bits>>8 & 0xff; |
| o3 = bits & 0xff; |
| |
| if (h3 == 64) enc += String.fromCharCode(o1); |
| else if (h4 == 64) enc += String.fromCharCode(o1, o2); |
| else enc += String.fromCharCode(o1, o2, o3); |
| } while (i < str.length); |
| |
| return decodeUTF8(enc); // decode UTF-8 byte-array back to Unicode |
| } |
| |
| function encodeUTF8(str) { // encode multi-byte string into utf-8 multiple single-byte characters |
| str = str.replace( |
| /[\u0080-\u07ff]/g, // U+0080 - U+07FF = 2-byte chars |
| function(c) { |
| var cc = c.charCodeAt(0); |
| return String.fromCharCode(0xc0 | cc>>6, 0x80 | cc&0x3f); } |
| ); |
| str = str.replace( |
| /[\u0800-\uffff]/g, // U+0800 - U+FFFF = 3-byte chars |
| function(c) { |
| var cc = c.charCodeAt(0); |
| return String.fromCharCode(0xe0 | cc>>12, 0x80 | cc>>6&0x3F, 0x80 | cc&0x3f); } |
| ); |
| return str; |
| } |
| |
| function decodeUTF8(str) { // decode utf-8 encoded string back into multi-byte characters |
| str = str.replace( |
| /[\u00c0-\u00df][\u0080-\u00bf]/g, // 2-byte chars |
| function(c) { |
| var cc = (c.charCodeAt(0)&0x1f)<<6 | c.charCodeAt(1)&0x3f; |
| return String.fromCharCode(cc); } |
| ); |
| str = str.replace( |
| /[\u00e0-\u00ef][\u0080-\u00bf][\u0080-\u00bf]/g, // 3-byte chars |
| function(c) { |
| var cc = (c.charCodeAt(0)&0x0f)<<12 | (c.charCodeAt(1)&0x3f<<6) | c.charCodeAt(2)&0x3f; |
| return String.fromCharCode(cc); } |
| ); |
| return str; |
| } |
| |
| |
| function byteArrayToHexStr(b) { // convert byte array to hex string for displaying test vectors |
| var s = ''; |
| for (var i=0; i<b.length; i++) s += b[i].toString(16) + ' '; |
| return s; |
| } |
| |
| /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */ |
| |
| |
| var plainText = "ROMEO: But, soft! what light through yonder window breaks?\n\ |
| It is the east, and Juliet is the sun.\n\ |
| Arise, fair sun, and kill the envious moon,\n\ |
| Who is already sick and pale with grief,\n\ |
| That thou her maid art far more fair than she:\n\ |
| Be not her maid, since she is envious;\n\ |
| Her vestal livery is but sick and green\n\ |
| And none but fools do wear it; cast it off.\n\ |
| It is my lady, O, it is my love!\n\ |
| O, that she knew she were!\n\ |
| She speaks yet she says nothing: what of that?\n\ |
| Her eye discourses; I will answer it.\n\ |
| I am too bold, 'tis not to me she speaks:\n\ |
| Two of the fairest stars in all the heaven,\n\ |
| Having some business, do entreat her eyes\n\ |
| To twinkle in their spheres till they return.\n\ |
| What if her eyes were there, they in her head?\n\ |
| The brightness of her cheek would shame those stars,\n\ |
| As daylight doth a lamp; her eyes in heaven\n\ |
| Would through the airy region stream so bright\n\ |
| That birds would sing and think it were not night.\n\ |
| See, how she leans her cheek upon her hand!\n\ |
| O, that I were a glove upon that hand,\n\ |
| That I might touch that cheek!\n\ |
| JULIET: Ay me!\n\ |
| ROMEO: She speaks:\n\ |
| O, speak again, bright angel! for thou art\n\ |
| As glorious to this night, being o'er my head\n\ |
| As is a winged messenger of heaven\n\ |
| Unto the white-upturned wondering eyes\n\ |
| Of mortals that fall back to gaze on him\n\ |
| When he bestrides the lazy-pacing clouds\n\ |
| And sails upon the bosom of the air."; |
| |
| var password = "O Romeo, Romeo! wherefore art thou Romeo?"; |
| |
| var cipherText = AESEncryptCtr(plainText, password, 256); |
| var decryptedText = AESDecryptCtr(cipherText, password, 256); |
| |
| if (decryptedText != plainText) |
| throw "ERROR: bad result: expected " + plainText + " but got " + decryptedText; |
| |