Example of AES256 encryption algorithm implemented by PHP

This article mainly introduces PHP's AES256 encryption algorithm, including the corresponding class files and demo instances, with another PHPmcrypt encryption instance for your reference, for more information about how to implement the AES256 encryption algorithm in PHP, see the following example. Share it with you for your reference. The details are as follows:

The aes. class. php file is as follows:

<?php /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */ /* AES implementation in PHP (c) Chris Veness 2005-2011. Right of free use is granted for all  */ /*  commercial or non-commercial use under CC-BY licence. No warranty of any form is offered.  */ /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */   class Aes {    /**   * AES Cipher function: encrypt 'input' with Rijndael algorithm   *   * @param input message as byte-array (16 bytes)   * @param w   key schedule as 2D byte-array (Nr+1 x Nb bytes) -   *       generated from the cipher key by keyExpansion()   * @return   ciphertext as byte-array (16 bytes)   */  public static function cipher($input, $w) {  // main cipher function [§5.1]   $Nb = 4;         // block size (in words): no of columns in state (fixed at 4 for AES)   $Nr = count($w)/$Nb - 1; // no of rounds: 10/12/14 for 128/192/256-bit keys     $state = array(); // initialise 4xNb byte-array 'state' with input [§3.4]   for ($i=0; $i<4*$Nb; $i++) $state[$i%4][floor($i/4)] = $input[$i];     $state = self::addRoundKey($state, $w, 0, $Nb);     for ($round=1; $round<$Nr; $round++) { // apply Nr rounds    $state = self::subBytes($state, $Nb);    $state = self::shiftRows($state, $Nb);    $state = self::mixColumns($state, $Nb);    $state = self::addRoundKey($state, $w, $round, $Nb);   }     $state = self::subBytes($state, $Nb);   $state = self::shiftRows($state, $Nb);   $state = self::addRoundKey($state, $w, $Nr, $Nb);     $output = array(4*$Nb); // convert state to 1-d array before returning [§3.4]   for ($i=0; $i<4*$Nb; $i++) $output[$i] = $state[$i%4][floor($i/4)];   return $output;  }      private static function addRoundKey($state, $w, $rnd, $Nb) { // xor Round Key into state S [§5.1.4]   for ($r=0; $r<4; $r++) {    for ($c=0; $c<$Nb; $c++) $state[$r][$c] ^= $w[$rnd*4+$c][$r];   }   return $state;  }    private static function subBytes($s, $Nb) {  // apply SBox to state S [§5.1.1]   for ($r=0; $r<4; $r++) {    for ($c=0; $c<$Nb; $c++) $s[$r][$c] = self::$sBox[$s[$r][$c]];   }   return $s;  }    private static function shiftRows($s, $Nb) {  // shift row r of state S left by r bytes [§5.1.2]   $t = array(4);   for ($r=1; $r<4; $r++) {    for ($c=0; $c<4; $c++) $t[$c] = $s[$r][($c+$r)%$Nb]; // shift into temp copy    for ($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 $s; // see fp.gladman.plus.com/cryptography_technology/rijndael/aes.spec.311.pdf   }    private static function mixColumns($s, $Nb) {  // combine bytes of each col of state S [§5.1.3]   for ($c=0; $c<4; $c++) {    $a = array(4); // 'a' is a copy of the current column from 's'    $b = array(4); // 'b' is a•{02} in GF(2^8)    for ($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 $s;  }    /**   * Key expansion for Rijndael cipher(): performs key expansion on cipher key   * to generate a key schedule   *   * @param key cipher key byte-array (16 bytes)   * @return  key schedule as 2D byte-array (Nr+1 x Nb bytes)   */  public static function keyExpansion($key) { // generate Key Schedule from Cipher Key [§5.2]   $Nb = 4;       // block size (in words): no of columns in state (fixed at 4 for AES)   $Nk = count($key)/4; // key length (in words): 4/6/8 for 128/192/256-bit keys   $Nr = $Nk + 6;    // no of rounds: 10/12/14 for 128/192/256-bit keys     $w = array();   $temp = array();     for ($i=0; $i<$Nk; $i++) {    $r = array($key[4*$i], $key[4*$i+1], $key[4*$i+2], $key[4*$i+3]);    $w[$i] = $r;   }     for ($i=$Nk; $i<($Nb*($Nr+1)); $i++) {    $w[$i] = array();    for ($t=0; $t<4; $t++) $temp[$t] = $w[$i-1][$t];    if ($i % $Nk == 0) {     $temp = self::subWord(self::rotWord($temp));     for ($t=0; $t<4; $t++) $temp[$t] ^= self::$rCon[$i/$Nk][$t];    } else if ($Nk > 6 && $i%$Nk == 4) {     $temp = self::subWord($temp);    }    for ($t=0; $t<4; $t++) $w[$i][$t] = $w[$i-$Nk][$t] ^ $temp[$t];   }   return $w;  }    private static function subWord($w) {  // apply SBox to 4-byte word w   for ($i=0; $i<4; $i++) $w[$i] = self::$sBox[$w[$i]];   return $w;  }    private static function rotWord($w) {  // rotate 4-byte word w left by one byte   $tmp = $w[0];   for ($i=0; $i<3; $i++) $w[$i] = $w[$i+1];   $w[3] = $tmp;   return $w;  }    // sBox is pre-computed multiplicative inverse in GF(2^8) used in subBytes and keyExpansion [§5.1.1]  private static $sBox = array(   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]  private static $rCon = array(    array(0x00, 0x00, 0x00, 0x00),   array(0x01, 0x00, 0x00, 0x00),   array(0x02, 0x00, 0x00, 0x00),   array(0x04, 0x00, 0x00, 0x00),   array(0x08, 0x00, 0x00, 0x00),   array(0x10, 0x00, 0x00, 0x00),   array(0x20, 0x00, 0x00, 0x00),   array(0x40, 0x00, 0x00, 0x00),   array(0x80, 0x00, 0x00, 0x00),   array(0x1b, 0x00, 0x00, 0x00),   array(0x36, 0x00, 0x00, 0x00) );  }  ?>

The file aesctr. class. php is as follows:

<?php /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */ /* AES counter (CTR) mode implementation in PHP (c) Chris Veness 2005-2011. Right of free use is */ /*  granted for all commercial or non-commercial use under CC-BY licence. No warranty of any  */ /*  form is offered.                                      */ /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */   class AesCtr extends Aes {    /**   * Encrypt a text using AES encryption in Counter mode of operation   * - see http://csrc.nist.gov/publications/nistpubs/800-38a/sp800-38a.pdf   *   * Unicode multi-byte character safe   *   * @param plaintext source text to be encrypted   * @param password the password to use to generate a key   * @param nBits   number of bits to be used in the key (128, 192, or 256)   * @param keep   keep 1:each not change 0:each change(default)   * @return     encrypted text   */  public static function encrypt($plaintext, $password, $nBits, $keep=0) {   $blockSize = 16; // block size fixed at 16 bytes / 128 bits (Nb=4) for AES   if (!($nBits==128 || $nBits==192 || $nBits==256)) return ''; // standard allows 128/192/256 bit keys   // note PHP (5) gives us plaintext and password in UTF8 encoding!      // use AES itself to encrypt password to get cipher key (using plain password as source for    // key expansion) - gives us well encrypted key   $nBytes = $nBits/8; // no bytes in key   $pwBytes = array();   for ($i=0; $i<$nBytes; $i++) $pwBytes[$i] = ord(substr($password,$i,1)) & 0xff;   $key = Aes::cipher($pwBytes, Aes::keyExpansion($pwBytes));   $key = array_merge($key, array_slice($key, 0, $nBytes-16)); // expand key to 16/24/32 bytes long      // initialise 1st 8 bytes of counter block with nonce (NIST SP800-38A §B.2): [0-1] = millisec,    // [2-3] = random, [4-7] = seconds, giving guaranteed sub-ms uniqueness up to Feb 2106   $counterBlock = array();    if($keep==0){     $nonce = floor(microtime(true)*1000);  // timestamp: milliseconds since 1-Jan-1970     $nonceMs = $nonce%1000;     $nonceSec = floor($nonce/1000);     $nonceRnd = floor(rand(0, 0xffff));   }else{     $nonce = 10000;     $nonceMs = $nonce%1000;     $nonceSec = floor($nonce/1000);     $nonceRnd = 10000;   }      for ($i=0; $i<2; $i++) $counterBlock[$i]  = self::urs($nonceMs, $i*8) & 0xff;   for ($i=0; $i<2; $i++) $counterBlock[$i+2] = self::urs($nonceRnd, $i*8) & 0xff;   for ($i=0; $i<4; $i++) $counterBlock[$i+4] = self::urs($nonceSec, $i*8) & 0xff;      // and convert it to a string to go on the front of the ciphertext   $ctrTxt = '';   for ($i=0; $i<8; $i++) $ctrTxt .= chr($counterBlock[$i]);     // generate key schedule - an expansion of the key into distinct Key Rounds for each round   $keySchedule = Aes::keyExpansion($key);   //print_r($keySchedule);      $blockCount = ceil(strlen($plaintext)/$blockSize);   $ciphertxt = array(); // ciphertext as array of strings      for ($b=0; $b<$blockCount; $b++) {    // set counter (block #) in last 8 bytes of counter block (leaving nonce in 1st 8 bytes)    // done in two stages for 32-bit ops: using two words allows us to go past 2^32 blocks (68GB)    for ($c=0; $c<4; $c++) $counterBlock[15-$c] = self::urs($b, $c*8) & 0xff;    for ($c=0; $c<4; $c++) $counterBlock[15-$c-4] = self::urs($b/0x100000000, $c*8);      $cipherCntr = Aes::cipher($counterBlock, $keySchedule); // -- encrypt counter block --      // block size is reduced on final block    $blockLength = $b<$blockCount-1 ? $blockSize : (strlen($plaintext)-1)%$blockSize+1;    $cipherByte = array();        for ($i=0; $i<$blockLength; $i++) { // -- xor plaintext with ciphered counter byte-by-byte --     $cipherByte[$i] = $cipherCntr[$i] ^ ord(substr($plaintext, $b*$blockSize+$i, 1));     $cipherByte[$i] = chr($cipherByte[$i]);    }    $ciphertxt[$b] = implode('', $cipherByte); // escape troublesome characters in ciphertext   }     // implode is more efficient than repeated string concatenation   $ciphertext = $ctrTxt . implode('', $ciphertxt);   $ciphertext = base64_encode($ciphertext);   return $ciphertext;  }    /**   * Decrypt a text encrypted by AES in counter mode of operation   *   * @param ciphertext source text to be decrypted   * @param password  the password to use to generate a key   * @param nBits   number of bits to be used in the key (128, 192, or 256)   * @return      decrypted text   */  public static function decrypt($ciphertext, $password, $nBits) {   $blockSize = 16; // block size fixed at 16 bytes / 128 bits (Nb=4) for AES   if (!($nBits==128 || $nBits==192 || $nBits==256)) return ''; // standard allows 128/192/256 bit keys   $ciphertext = base64_decode($ciphertext);     // use AES to encrypt password (mirroring encrypt routine)   $nBytes = $nBits/8; // no bytes in key   $pwBytes = array();   for ($i=0; $i<$nBytes; $i++) $pwBytes[$i] = ord(substr($password,$i,1)) & 0xff;   $key = Aes::cipher($pwBytes, Aes::keyExpansion($pwBytes));   $key = array_merge($key, array_slice($key, 0, $nBytes-16)); // expand key to 16/24/32 bytes long      // recover nonce from 1st element of ciphertext   $counterBlock = array();   $ctrTxt = substr($ciphertext, 0, 8);   for ($i=0; $i<8; $i++) $counterBlock[$i] = ord(substr($ctrTxt,$i,1));      // generate key schedule   $keySchedule = Aes::keyExpansion($key);     // separate ciphertext into blocks (skipping past initial 8 bytes)   $nBlocks = ceil((strlen($ciphertext)-8) / $blockSize);   $ct = array();   for ($b=0; $b<$nBlocks; $b++) $ct[$b] = substr($ciphertext, 8+$b*$blockSize, 16);   $ciphertext = $ct; // ciphertext is now array of block-length strings     // plaintext will get generated block-by-block into array of block-length strings   $plaintxt = array();      for ($b=0; $b<$nBlocks; $b++) {    // set counter (block #) in last 8 bytes of counter block (leaving nonce in 1st 8 bytes)    for ($c=0; $c<4; $c++) $counterBlock[15-$c] = self::urs($b, $c*8) & 0xff;    for ($c=0; $c<4; $c++) $counterBlock[15-$c-4] = self::urs(($b+1)/0x100000000-1, $c*8) & 0xff;      $cipherCntr = Aes::cipher($counterBlock, $keySchedule); // encrypt counter block      $plaintxtByte = array();    for ($i=0; $i
 
  >> operator nor unsigned ints   *   * @param a number to be shifted (32-bit integer)   * @param b number of bits to shift a to the right (0..31)   * @return  a right-shifted and zero-filled by b bits   */  private static function urs($a, $b) {   $a &= 0xffffffff; $b &= 0x1f; // (bounds check)   if ($a&0x80000000 && $b>0) {  // if left-most bit set    $a = ($a>>1) & 0x7fffffff;  //  right-shift one bit & clear left-most bit    $a = $a >> ($b-1);      //  remaining right-shifts   } else {            // otherwise    $a = ($a>>$b);        //  use normal right-shift   }    return $a;   } }  ?>
 

The Demo instance program is as follows:

<?php  require 'aes.class.php';   // AES PHP implementation require 'aesctr.class.php'; // AES Counter Mode implementation   echo 'each change
';  $mstr = AesCtr::encrypt('Hello World', 'key', 256); echo "Encrypt String : $mstr
";  $dstr = AesCtr::decrypt($mstr, 'key', 256); echo "Decrypt String : $dstr
";  echo 'each not change
';  $mstr = AesCtr::encrypt('Hello World', 'key', 256, 1); // keep=1 echo "Encrypt String : $mstr
";  $dstr = AesCtr::decrypt($mstr, 'key', 256); echo "Decrypt String : $dstr
"; ?> 

Here we will introduce another method for encryption and decryption using PHP mcrypt:

/* aes 256 encrypt * @param String $ostr * @param String $securekey * @param String $type encrypt, decrypt */ function aes($ostr, $securekey, $type='encrypt'){   if($ostr==''){     return '';   }      $key = $securekey;   $iv = strrev($securekey);   $td = mcrypt_module_open('rijndael-256', '', 'ofb', '');   mcrypt_generic_init($td, $key, $iv);    $str = '';    switch($type){     case 'encrypt':       $str = base64_encode(mcrypt_generic($td, $ostr));       break;      case 'decrypt':       $str = mdecrypt_generic($td, base64_decode($ostr));       break;   }    mcrypt_generic_deinit($td);    return $str; }  // Demo $key = "fdipzone201314showmethemoney!@#$"; $str = "show me the money";  $ostr = aes($str, $key); echo "String 1: $ostr
";  $dstr = aes($ostr, $key, 'decrypt'); echo "String 2: $dstr
";

I hope this article will help you learn php programming.