PHP - Class declarations may not be nested

17,479

Solution 1

Ok, this time I focused better and here's one possible problem/solution:

Can you post this file too: /var/www/html/myproject/cake/libs/log/file_log.php as it seems that error happens here and not in AES.php:

Fatal error: Class declarations may not be nested in /var/www/html/myproject/cake/libs/log/file_log.php on line 30

I think that Notice and Fatal Error are two different things that should not be mixed together. There is one notice about too big integer value (which is converted to float) and other fatal error about nesting classes inside each other.

How Aes and AesCtr should used:

Both Aes and AesCtr are fully static classes so ther's no point to instantiate them:

Change:

$aes = new AesCtr();
$decrypted = $aes->decrypt($encrypted, "mykey", 128); 

To:

$decrypted = AesCtr::decrypt($encrypted, "mykey", 128);

Yes you should drop $aes = new AesCtr(); as it is not needed when calling only static functions.

Here's about notice, AES.php line 230:

In AES.php at line 230 there is hex number 0x100000000 which is not valid signed 32-bit integer (in fact, it requires at least 33 bits even if unsigned), some PHP versions will throw an error or notice about it (older mostly). I am using PHP 5.3 and it will not notice anything even with error_reporting(E_ALL);

Signed integer maximum value is 2147483647 or in hex 0x7FFFFFFF and AES.php tries to use value of 4294967296 which is converted to floating point.

And, as language.types.integer.php says: There is no integer division operator in PHP. so that value should be converted to float anyway.

I think that problem is, as stated in error message Hex number is too big: 0x100000000, that php tries to use that hex value as integer but it is too big so it is converted to float first.

Some tests:

var_dump(0x100000000);
var_dump((int)0x100000000);

Output in 32bit system:

float(4294967296)
int(0)

And same with 64bit system:

int(4294967296)
int(4294967296)

How to fix it then?

Here's solution which may or may not work:

Simply replace 0x100000000 with 4294967296.0 so that line 230 will be like this:

for ($c=0; $c<4; $c++) $counterBlock[15-$c-4] = self::urs($b/4294967296.0, $c*8);

Maybe you should also check what urs() tries to do and how it try to do that. However it should already expecting floating point values as arguments, see integer division.

Update:

Checked that urs() seems to expect int as first arg, however it gets that from (x/y) operation which in PHP returns float if there is fractions and int otherwise.

To make it int again is simple type conversion using (int)(x/y), there is no drawbacks (or very little) compared to old way, this is only to convert it back.

Originally, before modifications, there was same possibility and propability of conversion to float as there is now (urs() doc says that first arg should be int).

for ($c=0; $c<4; $c++) $counterBlock[15-$c-4] = self::urs((int)($b/4294967296.0), $c*8);

Update: file_log.php

I think that there is nothing wrong with file_log.php, it declares class FileLog which is properly implemented and closed as far as i can see.

Other thing about file_log.php is that it seems that it is cakephp's internal library and loaded by cakephp framework. And I don't know anything about cakephp...

However, you really should test your code without AES.php or maybe try including AES.php some other way like this way to test if App::import() does not work correctly:

/* Remember to take into account that filenames are propably
 * case sensitive at server, but maybe case insensitive at
 * your workstation (if developing under windows). */

// If needed, change vendors/AES/AES.php to correct path:
require_once 'vendors/AES/AES.php';
$decrypted = AesCtr::decrypt($encrypted, "mykey", 128);

or maybe (from cakephp manual):

// Vendor not vendor and AES/AES not aes/AES or aes/aes just to be sure...
App::import('Vendor', 'AES/AES');
$decrypted = AesCtr::decrypt($encrypted, "mykey", 128);

or maybe drop it completely out:

$decrypted = 'dummytest';

or maybe include without using it at all:

App::import('vendor', 'aes', array('file' => 'AES/AES.php'));
$decrypted = 'dummytest';

instead of:

App::import('vendor', 'aes', array('file' => 'AES/AES.php'));
$decrypted = AesCtr::decrypt($encrypted, "mykey", 128);

This way problem is narrowed down, if same error still happens to pop up then problem is somewhere else but if error disappears after this test, then we know that error is either in App::import() or propably somewhere in cakephp framework.

Solution 2

I had once this kind of error because I added twice the name of a Model, e.g.

class MyModel extends AppModel
{
 var $name ='MyModel';
 ....
 var $name = 'Another Name';
}

In general, it is difficult to find the root cause of the problem: Sometimes the cause can be in places other than those you could suspect. For example, a mistake in Model can fire such kind of error.

Solution 3

I started having this error after a php update. Whenever i created a new php.ini, the error started to pop out. I tried to change error_reporting, display_errors and other settings, and the key to the error was the setting short_open_tag. (I still use old libraries without strict open tag, just "

So, the answer: set short_open_tag to "On" in php.ini, restarted apache and the error went away.

FYI: it happened to me after upgrading to OSX Maverick

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17,479
myrmix
Author by

myrmix

Updated on June 04, 2022

Comments

  • myrmix
    myrmix almost 2 years

    I have a project in cakephp, when I call a vendor for decrypting a string using AES, I get the error:

    Fatal error: Class declarations may not be nested in /var/www/html/myproject/cake/libs/log/file_log.php on line 30
    

    This is the code in my controller:

    App::import('vendor', 'aes', array('file' => 'AES/AES.php'));
    $aes = new AesCtr();
    $decrypted = $aes->decrypt($encrypted, "mykey", 128);
    

    And this is part of the vendor (one single file called AES.php):

    class Aes {
    //....Methods
    }
    
    class AesCtr extends Aes {
    
      public static function decrypt($ciphertext, $password, $nBits) {
      //....Method Logic
      }
    
      //....Other methods
    
    }
    

    I've read the explanation given here: PHP Nested classes work... sort of? but I have no much experience in PHP and wasn't able to solve this issue by the "hacky way" that they showed.

    Any help is appreciated. If more info is needed, please tell me.

    UPDATE Classes Aes and AesCtr (both are in file AES.php).

    <?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; $i<4*$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 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; $i<$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 = 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; $i<$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;
      }
    
      /* Decode Hexadecimal */
      public static function hexToStr($hex)
      {
        $string='';
        for ($i=0; $i < strlen($hex)-1; $i+=2)
        {
            $string .= chr(hexdec($hex[$i].$hex[$i+1]));
        }
        return $string;
      }
    
    
      /*
       * 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; 
      }
    
    }  
    /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -  */
    ?>
    

    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:

    Notice (8): Hex number is too big: 0x100000000 [CORE/vendors/AES/AES.php, line 230]

    Fatal error: Class declarations may not be nested in /var/www/html/myproject/cake/libs/log/file_log.php on line 30

    So I don't know if the error is in the code above or not.

    UPDATE 2: file_log.php, where the fatal error occurs (here is a description of the file)

    <?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' => LOGS);
            $this->_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 = $this->_path  . 'error.log';
            } elseif (in_array($type, $debugTypes)) {
                $filename = $this->_path . 'debug.log';
            } else {
                $filename = $this->_path . $type . '.log';
            }
            $output = date('Y-m-d H:i:s') . ' ' . ucfirst($type) . ': ' . $message . "\n";
            $log = new File($filename, true);
            if ($log->writable()) {
                return $log->append($output);
            }
        }
    }