nxs_Aes

The NextScripts: Social Networks Auto-Poster nxs Aes class.

Defined (1)

The class is defined in the following location(s).

/inc-cl/st.api.php  
  1. if (!class_exists('nxs_Aes')) { class nxs_Aes { 
  2. public static function cipher($input, $w) { // main cipher function [5.1] 
  3. $Nb = 4; // block size (in words): no of columns in state (fixed at 4 for AES) 
  4. $Nr = count($w)/$Nb - 1; // no of rounds: 10/12/14 for 128/192/256-bit keys 
  5.  
  6. $state = array(); // initialise 4xNb byte-array 'state' with input [3.4] 
  7. for ($i=0; $i<4*$Nb; $i++) $state[$i%4][floor($i/4)] = $input[$i]; 
  8.  
  9. $state = self::addRoundKey($state, $w, 0, $Nb); 
  10.  
  11. for ($round=1; $round<$Nr; $round++) { // apply Nr rounds 
  12. $state = self::subBytes($state, $Nb); 
  13. $state = self::shiftRows($state, $Nb); 
  14. $state = self::mixColumns($state, $Nb); 
  15. $state = self::addRoundKey($state, $w, $round, $Nb); 
  16.  
  17. $state = self::subBytes($state, $Nb); 
  18. $state = self::shiftRows($state, $Nb); 
  19. $state = self::addRoundKey($state, $w, $Nr, $Nb); 
  20.  
  21. $output = array(4*$Nb); // convert state to 1-d array before returning [3.4] 
  22. for ($i=0; $i<4*$Nb; $i++) $output[$i] = $state[$i%4][floor($i/4)]; 
  23. return $output; 
  24. private static function addRoundKey($state, $w, $rnd, $Nb) { // xor Round Key into state S [5.1.4] 
  25. for ($r=0; $r<4; $r++) { 
  26. for ($c=0; $c<$Nb; $c++) $state[$r][$c] ^= $w[$rnd*4+$c][$r]; 
  27. return $state; 
  28. private static function subBytes($s, $Nb) { // apply SBox to state S [5.1.1] 
  29. for ($r=0; $r<4; $r++) { 
  30. for ($c=0; $c<$Nb; $c++) $s[$r][$c] = self::$sBox[$s[$r][$c]]; 
  31. return $s; 
  32. private static function shiftRows($s, $Nb) { // shift row r of state S left by r bytes [5.1.2] 
  33. $t = array(4); 
  34. for ($r=1; $r<4; $r++) { 
  35. for ($c=0; $c<4; $c++) $t[$c] = $s[$r][($c+$r)%$Nb]; // shift into temp copy 
  36. for ($c=0; $c<4; $c++) $s[$r][$c] = $t[$c]; // and copy back 
  37. } // note that this will work for Nb=4, 5, 6, but not 7, 8 (always 4 for AES): 
  38. return $s; // see fp.gladman.plus.com/cryptography_technology/rijndael/aes.spec.311.pdf  
  39. private static function mixColumns($s, $Nb) { // combine bytes of each col of state S [5.1.3] 
  40. for ($c=0; $c<4; $c++) { 
  41. $a = array(4); // 'a' is a copy of the current column from 's' 
  42. $b = array(4); // 'b' is a{02} in GF(2^8) 
  43. for ($i=0; $i<4; $i++) { 
  44. $a[$i] = $s[$i][$c]; 
  45. $b[$i] = $s[$i][$c]&0x80 ? $s[$i][$c]<<1 ^ 0x011b : $s[$i][$c]<<1; 
  46. // a[n] ^ b[n] is a{03} in GF(2^8) 
  47. $s[0][$c] = $b[0] ^ $a[1] ^ $b[1] ^ $a[2] ^ $a[3]; // 2*a0 + 3*a1 + a2 + a3 
  48. $s[1][$c] = $a[0] ^ $b[1] ^ $a[2] ^ $b[2] ^ $a[3]; // a0 * 2*a1 + 3*a2 + a3 
  49. $s[2][$c] = $a[0] ^ $a[1] ^ $b[2] ^ $a[3] ^ $b[3]; // a0 + a1 + 2*a2 + 3*a3 
  50. $s[3][$c] = $a[0] ^ $b[0] ^ $a[1] ^ $a[2] ^ $b[3]; // 3*a0 + a1 + a2 + 2*a3 
  51. return $s; 
  52. public static function keyExpansion($key) { // generate Key Schedule from Cipher Key [5.2] 
  53. $Nb = 4; // block size (in words): no of columns in state (fixed at 4 for AES) 
  54. $Nk = count($key)/4; // key length (in words): 4/6/8 for 128/192/256-bit keys 
  55. $Nr = $Nk + 6; // no of rounds: 10/12/14 for 128/192/256-bit keys 
  56.  
  57. $w = array(); 
  58. $temp = array(); 
  59.  
  60. for ($i=0; $i<$Nk; $i++) { 
  61. $r = array($key[4*$i], $key[4*$i+1], $key[4*$i+2], $key[4*$i+3]); 
  62. $w[$i] = $r; 
  63.  
  64. for ($i=$Nk; $i<($Nb*($Nr+1)); $i++) { 
  65. $w[$i] = array(); 
  66. for ($t=0; $t<4; $t++) $temp[$t] = $w[$i-1][$t]; 
  67. if ($i % $Nk == 0) { 
  68. $temp = self::subWord(self::rotWord($temp)); 
  69. for ($t=0; $t<4; $t++) $temp[$t] ^= self::$rCon[$i/$Nk][$t]; 
  70. } else if ($Nk > 6 && $i%$Nk == 4) { 
  71. $temp = self::subWord($temp); 
  72. for ($t=0; $t<4; $t++) $w[$i][$t] = $w[$i-$Nk][$t] ^ $temp[$t]; 
  73. return $w; 
  74. private static function subWord($w) { // apply SBox to 4-byte word w 
  75. for ($i=0; $i<4; $i++) $w[$i] = self::$sBox[$w[$i]]; 
  76. return $w; 
  77. private static function rotWord($w) { // rotate 4-byte word w left by one byte 
  78. $tmp = $w[0]; 
  79. for ($i=0; $i<3; $i++) $w[$i] = $w[$i+1]; 
  80. $w[3] = $tmp; 
  81. return $w; 
  82. private static $sBox = array( 
  83. 0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76,  
  84. 0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0,  
  85. 0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15,  
  86. 0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75,  
  87. 0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84,  
  88. 0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf,  
  89. 0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8,  
  90. 0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2,  
  91. 0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73,  
  92. 0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb,  
  93. 0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79,  
  94. 0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08,  
  95. 0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a,  
  96. 0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e,  
  97. 0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf,  
  98. 0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16); 
  99. private static $rCon = array(  
  100. array(0x00, 0x00, 0x00, 0x00),  
  101. array(0x01, 0x00, 0x00, 0x00),  
  102. array(0x02, 0x00, 0x00, 0x00),  
  103. array(0x04, 0x00, 0x00, 0x00),  
  104. array(0x08, 0x00, 0x00, 0x00),  
  105. array(0x10, 0x00, 0x00, 0x00),  
  106. array(0x20, 0x00, 0x00, 0x00),  
  107. array(0x40, 0x00, 0x00, 0x00),  
  108. array(0x80, 0x00, 0x00, 0x00),  
  109. array(0x1b, 0x00, 0x00, 0x00),  
  110. array(0x36, 0x00, 0x00, 0x00) );  
  111. } }