AES.js 12 KB

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  1. (function () {
  2. var C = typeof window === 'undefined' ? require('./Crypto').Crypto : window.Crypto;
  3. // Shortcuts
  4. var util = C.util;
  5. var charenc = C.charenc;
  6. var UTF8 = charenc.UTF8; // Precomputed SBOX
  7. var SBOX = [
  8. 99, 124, 119, 123, 242, 107, 111, 197, 48, 1, 103, 43, 254, 215, 171, 118, 202, 130, 201, 125, 250, 89, 71, 240, 173, 212, 162, 175, 156, 164, 114, 192, 183, 253, 147, 38,
  9. 54, 63, 247, 204, 52, 165, 229, 241, 113, 216, 49, 21, 4, 199, 35, 195, 24, 150, 5, 154, 7, 18, 128, 226, 235, 39, 178, 117, 9, 131, 44, 26, 27, 110, 90, 160, 82, 59, 214,
  10. 179, 41, 227, 47, 132, 83, 209, 0, 237, 32, 252, 177, 91, 106, 203, 190, 57, 74, 76, 88, 207, 208, 239, 170, 251, 67, 77, 51, 133, 69, 249, 2, 127, 80, 60, 159, 168, 81,
  11. 163, 64, 143, 146, 157, 56, 245, 188, 182, 218, 33, 16, 255, 243, 210, 205, 12, 19, 236, 95, 151, 68, 23, 196, 167, 126, 61, 100, 93, 25, 115, 96, 129, 79, 220, 34, 42,
  12. 144, 136, 70, 238, 184, 20, 222, 94, 11, 219, 224, 50, 58, 10, 73, 6, 36, 92, 194, 211, 172, 98, 145, 149, 228, 121, 231, 200, 55, 109, 141, 213, 78, 169, 108, 86, 244,
  13. 234, 101, 122, 174, 8, 186, 120, 37, 46, 28, 166, 180, 198, 232, 221, 116, 31, 75, 189, 139, 138, 112, 62, 181, 102, 72, 3, 246, 14, 97, 53, 87, 185, 134, 193, 29, 158,
  14. 225, 248, 152, 17, 105, 217, 142, 148, 155, 30, 135, 233, 206, 85, 40, 223, 140, 161, 137, 13, 191, 230, 66, 104, 65, 153, 45, 15, 176, 84, 187, 22
  15. ];
  16. // Compute inverse SBOX lookup table
  17. for (var INVSBOX = [], i = 0; i < 256; i++) {
  18. INVSBOX[SBOX[i]] = i;
  19. }
  20. // Compute mulitplication in GF(2^8) lookup tables
  21. var MULT2 = [];
  22. var MULT3 = [];
  23. var MULT9 = [];
  24. var MULTB = [];
  25. var MULTD = [];
  26. var MULTE = [];
  27. function xtime(a, b) {
  28. for (var result = 0, i = 0; i < 8; i++) {
  29. if (b & 1) {
  30. result ^= a;
  31. }
  32. var hiBitSet = a & 128;
  33. a = (a << 1) & 255;
  34. if (hiBitSet) {
  35. a ^= 27;
  36. }
  37. b >>>= 1;
  38. }
  39. return result;
  40. }
  41. for (var i = 0; i < 256; i++) {
  42. MULT2[i] = xtime(i, 2);
  43. MULT3[i] = xtime(i, 3);
  44. MULT9[i] = xtime(i, 9);
  45. MULTB[i] = xtime(i, 11);
  46. MULTD[i] = xtime(i, 13);
  47. MULTE[i] = xtime(i, 14);
  48. }
  49. // Precomputed RCon lookup
  50. var RCON = [0, 1, 2, 4, 8, 16, 32, 64, 128, 27, 54];
  51. // Inner state
  52. var state = [[], [], [], []];
  53. var keylength;
  54. var nrounds;
  55. var keyschedule;
  56. var AES = (C.AES = {
  57. /**
  58. * Public API
  59. */
  60. encrypt: function (message, password, options) {
  61. options = options || {};
  62. // Determine mode
  63. var mode = options.mode || new C.mode.OFB();
  64. // Allow mode to override options
  65. if (mode.fixOptions) {
  66. mode.fixOptions(options);
  67. }
  68. var // Convert to bytes if message is a string
  69. m = message.constructor == String ? UTF8.stringToBytes(message) : message;
  70. var // Generate random IV
  71. iv = options.iv || util.randomBytes(AES._blocksize * 4);
  72. var // Generate key
  73. k =
  74. password.constructor == String
  75. ? // Derive key from passphrase
  76. C.PBKDF2(password, iv, 32, {
  77. asBytes: true
  78. })
  79. : // else, assume byte array representing cryptographic key
  80. password; // Encrypt
  81. AES._init(k);
  82. mode.encrypt(AES, m, iv);
  83. // Return ciphertext
  84. m = options.iv ? m : iv.concat(m);
  85. return options && options.asBytes ? m : util.bytesToBase64(m);
  86. },
  87. decrypt: function (ciphertext, password, options) {
  88. options = options || {};
  89. // Determine mode
  90. var mode = options.mode || new C.mode.OFB();
  91. // Allow mode to override options
  92. if (mode.fixOptions) {
  93. mode.fixOptions(options);
  94. }
  95. var // Convert to bytes if ciphertext is a string
  96. c = ciphertext.constructor == String ? util.base64ToBytes(ciphertext) : ciphertext;
  97. var // Separate IV and message
  98. iv = options.iv || c.splice(0, AES._blocksize * 4);
  99. var // Generate key
  100. k =
  101. password.constructor == String
  102. ? // Derive key from passphrase
  103. C.PBKDF2(password, iv, 32, {
  104. asBytes: true
  105. })
  106. : // else, assume byte array representing cryptographic key
  107. password; // Decrypt
  108. AES._init(k);
  109. mode.decrypt(AES, c, iv);
  110. // Return plaintext
  111. return options && options.asBytes ? c : UTF8.bytesToString(c);
  112. },
  113. /**
  114. * Package private methods and properties
  115. */
  116. _blocksize: 4,
  117. _encryptblock: function (m, offset) {
  118. // Set input
  119. for (var row = 0; row < AES._blocksize; row++) {
  120. for (var col = 0; col < 4; col++) {
  121. state[row][col] = m[offset + col * 4 + row];
  122. }
  123. }
  124. // Add round key
  125. for (var row = 0; row < 4; row++) {
  126. for (var col = 0; col < 4; col++) {
  127. state[row][col] ^= keyschedule[col][row];
  128. }
  129. }
  130. for (var round = 1; round < nrounds; round++) {
  131. // Sub bytes
  132. for (var row = 0; row < 4; row++) {
  133. for (var col = 0; col < 4; col++) {
  134. state[row][col] = SBOX[state[row][col]];
  135. }
  136. }
  137. // Shift rows
  138. state[1].push(state[1].shift());
  139. state[2].push(state[2].shift());
  140. state[2].push(state[2].shift());
  141. state[3].unshift(state[3].pop());
  142. // Mix columns
  143. for (var col = 0; col < 4; col++) {
  144. var s0 = state[0][col];
  145. var s1 = state[1][col];
  146. var s2 = state[2][col];
  147. var s3 = state[3][col];
  148. state[0][col] = MULT2[s0] ^ MULT3[s1] ^ s2 ^ s3;
  149. state[1][col] = s0 ^ MULT2[s1] ^ MULT3[s2] ^ s3;
  150. state[2][col] = s0 ^ s1 ^ MULT2[s2] ^ MULT3[s3];
  151. state[3][col] = MULT3[s0] ^ s1 ^ s2 ^ MULT2[s3];
  152. }
  153. // Add round key
  154. for (var row = 0; row < 4; row++) {
  155. for (var col = 0; col < 4; col++) {
  156. state[row][col] ^= keyschedule[round * 4 + col][row];
  157. }
  158. }
  159. }
  160. // Sub bytes
  161. for (var row = 0; row < 4; row++) {
  162. for (var col = 0; col < 4; col++) {
  163. state[row][col] = SBOX[state[row][col]];
  164. }
  165. }
  166. // Shift rows
  167. state[1].push(state[1].shift());
  168. state[2].push(state[2].shift());
  169. state[2].push(state[2].shift());
  170. state[3].unshift(state[3].pop());
  171. // Add round key
  172. for (var row = 0; row < 4; row++) {
  173. for (var col = 0; col < 4; col++) {
  174. state[row][col] ^= keyschedule[nrounds * 4 + col][row];
  175. }
  176. }
  177. // Set output
  178. for (var row = 0; row < AES._blocksize; row++) {
  179. for (var col = 0; col < 4; col++) {
  180. m[offset + col * 4 + row] = state[row][col];
  181. }
  182. }
  183. },
  184. _decryptblock: function (c, offset) {
  185. // Set input
  186. for (var row = 0; row < AES._blocksize; row++) {
  187. for (var col = 0; col < 4; col++) {
  188. state[row][col] = c[offset + col * 4 + row];
  189. }
  190. }
  191. // Add round key
  192. for (var row = 0; row < 4; row++) {
  193. for (var col = 0; col < 4; col++) {
  194. state[row][col] ^= keyschedule[nrounds * 4 + col][row];
  195. }
  196. }
  197. for (var round = 1; round < nrounds; round++) {
  198. // Inv shift rows
  199. state[1].unshift(state[1].pop());
  200. state[2].push(state[2].shift());
  201. state[2].push(state[2].shift());
  202. state[3].push(state[3].shift());
  203. // Inv sub bytes
  204. for (var row = 0; row < 4; row++) {
  205. for (var col = 0; col < 4; col++) {
  206. state[row][col] = INVSBOX[state[row][col]];
  207. }
  208. }
  209. // Add round key
  210. for (var row = 0; row < 4; row++) {
  211. for (var col = 0; col < 4; col++) {
  212. state[row][col] ^= keyschedule[(nrounds - round) * 4 + col][row];
  213. }
  214. }
  215. // Inv mix columns
  216. for (var col = 0; col < 4; col++) {
  217. var s0 = state[0][col];
  218. var s1 = state[1][col];
  219. var s2 = state[2][col];
  220. var s3 = state[3][col];
  221. state[0][col] = MULTE[s0] ^ MULTB[s1] ^ MULTD[s2] ^ MULT9[s3];
  222. state[1][col] = MULT9[s0] ^ MULTE[s1] ^ MULTB[s2] ^ MULTD[s3];
  223. state[2][col] = MULTD[s0] ^ MULT9[s1] ^ MULTE[s2] ^ MULTB[s3];
  224. state[3][col] = MULTB[s0] ^ MULTD[s1] ^ MULT9[s2] ^ MULTE[s3];
  225. }
  226. }
  227. // Inv shift rows
  228. state[1].unshift(state[1].pop());
  229. state[2].push(state[2].shift());
  230. state[2].push(state[2].shift());
  231. state[3].push(state[3].shift());
  232. // Inv sub bytes
  233. for (var row = 0; row < 4; row++) {
  234. for (var col = 0; col < 4; col++) {
  235. state[row][col] = INVSBOX[state[row][col]];
  236. }
  237. }
  238. // Add round key
  239. for (var row = 0; row < 4; row++) {
  240. for (var col = 0; col < 4; col++) {
  241. state[row][col] ^= keyschedule[col][row];
  242. }
  243. }
  244. // Set output
  245. for (var row = 0; row < AES._blocksize; row++) {
  246. for (var col = 0; col < 4; col++) {
  247. c[offset + col * 4 + row] = state[row][col];
  248. }
  249. }
  250. },
  251. /**
  252. * Private methods
  253. */
  254. _init: function (k) {
  255. keylength = k.length / 4;
  256. nrounds = keylength + 6;
  257. AES._keyexpansion(k);
  258. },
  259. // Generate a key schedule
  260. _keyexpansion: function (k) {
  261. keyschedule = [];
  262. for (var row = 0; row < keylength; row++) {
  263. keyschedule[row] = [k[row * 4], k[row * 4 + 1], k[row * 4 + 2], k[row * 4 + 3]];
  264. }
  265. for (var row = keylength; row < AES._blocksize * (nrounds + 1); row++) {
  266. var temp = [keyschedule[row - 1][0], keyschedule[row - 1][1], keyschedule[row - 1][2], keyschedule[row - 1][3]];
  267. if (row % keylength == 0) {
  268. // Rot word
  269. temp.push(temp.shift());
  270. // Sub word
  271. temp[0] = SBOX[temp[0]];
  272. temp[1] = SBOX[temp[1]];
  273. temp[2] = SBOX[temp[2]];
  274. temp[3] = SBOX[temp[3]];
  275. temp[0] ^= RCON[row / keylength];
  276. } else if (keylength > 6 && row % keylength == 4) {
  277. // Sub word
  278. temp[0] = SBOX[temp[0]];
  279. temp[1] = SBOX[temp[1]];
  280. temp[2] = SBOX[temp[2]];
  281. temp[3] = SBOX[temp[3]];
  282. }
  283. keyschedule[row] = [
  284. keyschedule[row - keylength][0] ^ temp[0],
  285. keyschedule[row - keylength][1] ^ temp[1],
  286. keyschedule[row - keylength][2] ^ temp[2],
  287. keyschedule[row - keylength][3] ^ temp[3]
  288. ];
  289. }
  290. }
  291. });
  292. })();