title: PHP - Class declarations may not be nested
body: <p>I have a project in cakephp, when I call a vendor for decrypting a string using AES, I get the error: </p>
  
  <pre><code>Fatal error: Class declarations may not be nested in /var/www/html/myproject/cake/libs/log/file_log.php on line 30
  </code></pre>
  
  <p>This is the code in my controller:</p>
  
  <pre><code>App::import('vendor', 'aes', array('file' =&gt; 'AES/AES.php'));
  $aes = new AesCtr();
  $decrypted = $aes-&gt;decrypt($encrypted, "mykey", 128);
  </code></pre>
  
  <p>And this is part of the vendor (one single file called AES.php):</p>
  
  <pre><code>class Aes {
  //....Methods
  }
  
  class AesCtr extends Aes {
  
    public static function decrypt($ciphertext, $password, $nBits) {
    //....Method Logic
    }
  
    //....Other methods
  
  }
  </code></pre>
  
  <p>I've read the explanation given here: <a href="https://stackoverflow.com/questions/2608432/php-nested-classes-work-sort-of">PHP Nested classes work... sort of?</a>
  but I have no much experience in PHP and wasn't able to solve this issue by the "hacky way" that they showed.</p>
  
  <p>Any help is appreciated. If more info is needed, please tell me.</p>
  
  <p>UPDATE
  Classes Aes and AesCtr (both are in file AES.php).</p>
  
  <pre><code>&lt;?php
  /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -  */
  /*  AES implementation in PHP                                                                     */
  /*    (c) Chris Veness 2005-2011 www.movable-type.co.uk/scripts                                   */
  /*    Right of free use is granted for all commercial or non-commercial use providing this        */
  /*    copyright notice is retainded. 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; $i&lt;4*$Nb; $i++) $state[$i%4][floor($i/4)] = $input[$i];
  
      $state = self::addRoundKey($state, $w, 0, $Nb);
  
      for ($round=1; $round&lt;$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; $i&lt;4*$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&lt;4; $r++) {
        for ($c=0; $c&lt;$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&lt;4; $r++) {
        for ($c=0; $c&lt;$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&lt;4; $r++) {
        for ($c=0; $c&lt;4; $c++) $t[$c] = $s[$r][($c+$r)%$Nb];  // shift into temp copy
        for ($c=0; $c&lt;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&lt;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&lt;4; $i++) {
          $a[$i] = $s[$i][$c];
          $b[$i] = $s[$i][$c]&amp;0x80 ? $s[$i][$c]&lt;&lt;1 ^ 0x011b : $s[$i][$c]&lt;&lt;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; $i&lt;$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; $i&lt;($Nb*($Nr+1)); $i++) {
        $w[$i] = array();
        for ($t=0; $t&lt;4; $t++) $temp[$t] = $w[$i-1][$t];
        if ($i % $Nk == 0) {
          $temp = self::subWord(self::rotWord($temp));
          for ($t=0; $t&lt;4; $t++) $temp[$t] ^= self::$rCon[$i/$Nk][$t];
        } else if ($Nk &gt; 6 &amp;&amp; $i%$Nk == 4) {
          $temp = self::subWord($temp);
        }
        for ($t=0; $t&lt;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&lt;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&lt;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) ); 
  
  } 
  
  /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -  */
  ?&gt;
  
  &lt;?php
  /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -  */
  /*  AES counter (CTR) mode implementation in PHP                                                  */
  /*    (c) Chris Veness 2005-2011 www.movable-type.co.uk/scripts                                   */
  /*    Right of free use is granted for all commercial or non-commercial use providing this        */
  /*    copyright notice is retainded. 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; $i&lt;$nBytes; $i++) $pwBytes[$i] = ord(substr($password,$i,1)) &amp; 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&lt;2; $i++) $counterBlock[$i]   = self::urs($nonceMs,  $i*8) &amp; 0xff;
      for ($i=0; $i&lt;2; $i++) $counterBlock[$i+2] = self::urs($nonceRnd, $i*8) &amp; 0xff;
      for ($i=0; $i&lt;4; $i++) $counterBlock[$i+4] = self::urs($nonceSec, $i*8) &amp; 0xff;
  
      // and convert it to a string to go on the front of the ciphertext
      $ctrTxt = '';
      for ($i=0; $i&lt;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; $b&lt;$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&lt;4; $c++) $counterBlock[15-$c] = self::urs($b, $c*8) &amp; 0xff;
        for ($c=0; $c&lt;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 = $b&lt;$blockCount-1 ? $blockSize : (strlen($plaintext)-1)%$blockSize+1;
        $cipherByte = array();
  
        for ($i=0; $i&lt;$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 = AesCtr::hexToStr($ciphertext);
      $ciphertext = base64_decode($ciphertext);
  
  
      // use AES to encrypt password (mirroring encrypt routine)
      $nBytes = $nBits/8;  // no bytes in key
      $pwBytes = array();
      for ($i=0; $i&lt;$nBytes; $i++) $pwBytes[$i] = ord(substr($password,$i,1)) &amp; 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&lt;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; $b&lt;$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; $b&lt;$nBlocks; $b++) {
        // set counter (block #) in last 8 bytes of counter block (leaving nonce in 1st 8 bytes)
        for ($c=0; $c&lt;4; $c++) $counterBlock[15-$c] = self::urs($b, $c*8) &amp; 0xff;
        for ($c=0; $c&lt;4; $c++) $counterBlock[15-$c-4] = self::urs(($b+1)/0x100000000-1, $c*8) &amp; 0xff;
  
        $cipherCntr = Aes::cipher($counterBlock, $keySchedule);  // encrypt counter block
  
        $plaintxtByte = array();
        for ($i=0; $i&lt;strlen($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;
    }
  
    /* Decode Hexadecimal */
    public static function hexToStr($hex)
    {
      $string='';
      for ($i=0; $i &lt; strlen($hex)-1; $i+=2)
      {
          $string .= chr(hexdec($hex[$i].$hex[$i+1]));
      }
      return $string;
    }
  
  
    /*
     * Unsigned right shift function, since PHP has neither &gt;&gt;&gt; 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 &amp;= 0xffffffff; $b &amp;= 0x1f;  // (bounds check)
      if ($a&amp;0x80000000 &amp;&amp; $b&gt;0) {   // if left-most bit set
        $a = ($a&gt;&gt;1) &amp; 0x7fffffff;   //   right-shift one bit &amp; clear left-most bit
        $a = $a &gt;&gt; ($b-1);           //   remaining right-shifts
      } else {                       // otherwise
        $a = ($a&gt;&gt;$b);               //   use normal right-shift
      } 
      return $a; 
    }
  
  }  
  /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -  */
  ?&gt;
  </code></pre>
  
  <p>Sorry I should have mentioned this, this code works well on my computer, I get that error when I upload the project to a server, and the complete message is:</p>
  
  <blockquote>
    <p>Notice (8): Hex number is too big: 0x100000000
    [CORE/vendors/AES/AES.php, line 230]</p>
    
    <p>Fatal error: Class declarations may not be nested in
    /var/www/html/myproject/cake/libs/log/file_log.php on line 30</p>
  </blockquote>
  
  <p>So I don't know if the error is in the code above or not.</p>
  
  <p>UPDATE 2: file_log.php, where the fatal error occurs (here is a <a href="http://api13.cakephp.org/file/cake/libs/log/file_log.php" rel="nofollow noreferrer">description of the file</a>)</p>
  
  <pre><code>&lt;?php
  /**
   * File Storage stream for Logging
   *
   * PHP versions 4 and 5
   *
   * CakePHP(tm) :  Rapid Development Framework (http://cakephp.org)
   * Copyright 2005-2010, Cake Software Foundation, Inc. (http://cakefoundation.org)
   *
   * Licensed under The MIT License
   * Redistributions of files must retain the above copyright notice.
   *
   * @copyright     Copyright 2005-2010, Cake Software Foundation, Inc. (http://cakefoundation.org)
   * @link          http://www.cakefoundation.org/projects/info/cakephp CakePHP(tm) Project
   * @package       cake
   * @subpackage    cake.cake.libs.log
   * @since         CakePHP(tm) v 1.3
   * @license       MIT License (http://www.opensource.org/licenses/mit-license.php)
   */
  if (!class_exists('File')) {
      require LIBS . 'file.php';
  }
  /**
   * File Storage stream for Logging.  Writes logs to different files
   * based on the type of log it is.
   *
   * @package cake
   * @subpackage cake.cake.libs.log
   */
  class FileLog {
  
  /**
   * Path to save log files on.
   *
   * @var string
   */
      var $_path = null;
  
  /**
   * Constructs a new File Logger.
   * 
   * Options
   *
   * - `path` the path to save logs on.
   *
   * @param array $options Options for the FileLog, see above.
   * @return void
   */
      function FileLog($options = array()) {
          $options += array('path' =&gt; LOGS);
          $this-&gt;_path = $options['path'];
      }
  
  /**
   * Implements writing to log files.
   *
   * @param string $type The type of log you are making.
   * @param string $message The message you want to log.
   * @return boolean success of write.
   */
      function write($type, $message) {
          $debugTypes = array('notice', 'info', 'debug');
  
          if ($type == 'error' || $type == 'warning') {
              $filename = $this-&gt;_path  . 'error.log';
          } elseif (in_array($type, $debugTypes)) {
              $filename = $this-&gt;_path . 'debug.log';
          } else {
              $filename = $this-&gt;_path . $type . '.log';
          }
          $output = date('Y-m-d H:i:s') . ' ' . ucfirst($type) . ': ' . $message . "\n";
          $log = new File($filename, true);
          if ($log-&gt;writable()) {
              return $log-&gt;append($output);
          }
      }
  }
  </code></pre>