PHP的AES加密类

PHP的AES加密类

aes.php

<?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) ); 

}
 
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -  */
?>

<?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)
   * @return          encrypted text
   */
  public static function encrypt($plaintext, $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
    // 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();
    $nonce = floor(microtime(true)*1000);   // timestamp: milliseconds since 1-Jan-1970
    $nonceMs = $nonce%1000;
    $nonceSec = floor($nonce/1000);
    $nonceRnd = floor(rand(0, 0xffff));
   
    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; $i<strlen($ciphertext[$b]); $i++) {
        // -- xor plaintext with ciphered counter byte-by-byte --
        $plaintxtByte[$i] = $cipherCntr[$i] ^ ord(substr($ciphertext[$b],$i,1));
        $plaintxtByte[$i] = chr($plaintxtByte[$i]);
     
      }
      $plaintxt[$b] = implode('', $plaintxtByte);
    }
 
    // join array of blocks into single plaintext string
    $plaintext = implode('',$plaintxt);
   
    return $plaintext;
  }
 
 
  /*
   * Unsigned right shift function, since PHP has neither >>> 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;
  }

}  
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -  */
?>

[PHP]代码

The following Test Harness illustrates server-side encryption and decryption using the PHP AES script.
It provides fields to enter the password and plaintext message, and then invokes itself to encrypt the plaintext and/or decrypt the ciphertext.

<?php
  require 'aes.class.php';     // AES PHP implementation
  require 'aesctr.class.php';  // AES Counter Mode implementation
 
  $timer = microtime(true);
 
  // initialise password & plaintesxt if not set in post array (shouldn't need stripslashes if magic_quotes is off)
  $pw = isset($_POST['pw']) ? stripslashes($_POST['pw']) : 'L0ck it up saf3';
  $pt = isset($_POST['pt']) ? stripslashes($_POST['pt']) : 'pssst ... đon’t tell anyøne!';
  $cipher = isset($_POST['cipher']) ? $_POST['cipher']: '';
  $plain = isset($_POST['plain']) ? stripslashes($_POST['plain']): '';
  $encr = isset($_POST['encr']) ? AesCtr::encrypt($pt, $pw, 256) : $cipher;
  $decr = isset($_POST['decr']) ? AesCtr::decrypt($_POST['cipher'], $pw, 256) : $plain;
?>  
<!DOCTYPE html>
<html lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>AES in PHP test harness</title>
</head>
<body>
<form name="frm" id="frm" method="post" action=""> <!-- same-document reference -->
  <table>  
    <tr>
      <td>Password:</td>
      <td><input type="text" name="pw" size="16" value="<?= $pw ?>"></td>
    </tr>
    <tr>
      <td>Plaintext:</td>
      <td><input type="text" name="pt" size="40" value="<?= htmlspecialchars($pt) ?>"></td>
    </tr>
    <tr>
      <td><input type="submit" name="encr" value="Encrypt it:"></td>
      <td><input type="text" name="cipher" size="80" value="<?= $encr ?>"></td>
    </tr>
    <tr>
      <td><input type="submit" name="decr" value="Decrypt it:"></td>
      <td><input type="text" name="plain" size="40" value="<?= htmlspecialchars($decr) ?>"></td>
    </tr>
  </table>
</form>
<p><?= intval((microtime(true) - $timer)*1000) ?>ms</p>
</body>
</html>

The following Test Harness illustrates a possible way of integrating JavaScript encoding with PHP decoding.
The HTML file presents fields to enter the plaintext message. It uses the JavaScript version to encrypt the message client-side, and invokes the PHP file passing the ciphertext in the POST array. The PHP script then uses the PHP version to decrypt the ciphertext passed in the POST array and display it.
Of course, any real application would use a more sophisticated approach to password management!

aes-js-php.html:
<!DOCTYPE html>
<html lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>AES JavaScript+PHP test harness (client-side encrypt)</title>
<script type="text/javascript" src="aes.js">/* AES JavaScript implementation */</script>
<script type="text/javascript" src="aes-ctr.js">/* AES Counter Mode implementation */</script>
<script type="text/javascript" src="base64.js">/* Base64 encoding */</script>
<script type="text/javascript" src="utf8.js">/* UTF-8 encoding */</script>
</head>
<body>
<!-- encrypt the message before submitting the form -->
<form name="frm" id="frm" method="post" action="aes-js-php.php"
      onsubmit="frm.message.value = Aes.Ctr.encrypt(frm.message.value, 'L0ck it up saf3', 256);">
  <p>Message: <input type="text" name="message" id="message" size="40" value=""></p>
  <p><input type="submit" value="Encrypt it:"></p>
</form>
</body>
</html>

aes-js-php.php:
<?php
  require 'aes.class.php';     // AES PHP implementation
  require 'aesctr.class.php';  // AES Counter Mode implementation
?>
<!DOCTYPE html>
<html lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>AES JavaScript+PHP test harness (server-side decrypt)</title>
</head>
<body>
<!-- output the post array received and dectypt the message -->
<pre>$_POST: <?= print_r($_POST, true) ?></pre>
<pre>Plaintext: <?= AesCtr::decrypt($_POST['message'], 'L0ck it up saf3', 256) ?></pre>
</body>
</html>