Encriptar en AES128 en un sitio y desencriptar en otro

[negrocebollin]

Hola gente,

Tengo un código PHP en un server con un enlace que manda un parámetro codificado en AES128 de este tipo:

<a href="otroserver.php?param=estocodificadoenAES128" />Click</a>

En otroserver.php tengo el código en teoría para descifrarlo, pero por más que lo intento no lo logro. La idea es coger ese parámetro y descodificarlo.

En codificar.php tengo el siguiente código

Código:

<?php
// This PHP code snippet provides a basic understanding of 
	// PHP's AES encryption.

	// The first thing to understand is the meaning of these constants:
	// MCRYPT_RIJNDAEL_128
	// MCRYPT_RIJNDAEL_192
	// MCRYPT_RIJNDAEL_256
	// You would think that MCRYPT_RIJNDAEL_256 specifies 256-bit encryption,
	// but that is wrong.  The three choices specify the block-size to be used
	// with Rijndael encryption.  They say nothing about the key size (i.e. strength)
	// of the encryption.  (Read further to understand how the strength of the
	// AES encryption is set.)
	//
	// The Rijndael encyrption algorithm is a block cipher.  It operates on discrete 
	// blocks of data.  Padding MUST be added such that
    // the data to be encrypted has a length that is a multiple of the block size.
	// (PHP pads with NULL bytes)
	// Thus, if you specify MCRYPT_RIJNDAEL_256, your encrypted output will always
	// be a multiple of 32 bytes (i.e. 256 bits).  If you specify MCRYPT_RIJNDAEL_128,
	// your encrypted output will always be a multiple of 16 bytes.
	//
	// Note: Strictly speaking, AES is not precisely Rijndael (although in practice 
	// they are used interchangeably) as Rijndael supports a larger range of block 
	// and key sizes; AES has a fixed block size of 128 bits and a key size of 
	// 128, 192, or 256 bits, whereas Rijndael can be specified with key and block 
	// sizes in any multiple of 32 bits, with a minimum of 128 bits and a maximum of 
	// 256 bits.
	// In summary: If you want to be AES compliant, always choose MCRYPT_RIJNDAEL_128.
	//
	// So the first step is to create the cipher object:
	$cipher = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', MCRYPT_MODE_CBC, '');
	
	// We're using CBC mode (cipher-block chaining).  Block cipher modes are detailed
	// here: http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation
		
	// CBC mode requires an initialization vector.  The size of the IV (initialization
	// vector) is always equal to the block-size.  (It is NOT equal to the key size.)
	// Given that our block size is 128-bits, the IV is also 128-bits (i.e. 16 bytes).
	// Thus, for AES encryption, the IV is always 16 bytes regardless of the 
	// strength of encryption.
	// 
	// Here's some PHP code to verify our IV size:
	$iv_size = mcrypt_enc_get_iv_size($cipher);
	printf("iv_size = %d\n",$iv_size);
	
	// How do you do 256-bit AES encryption in PHP vs. 128-bit AES encryption???
	// The answer is:  Give it a key that's 32 bytes long as opposed to 16 bytes long.
	// For example:
	$key128 = '1234567890123456';
	
	// Here's our 128-bit IV which is used for both 256-bit and 128-bit keys.
	$iv =  '1234567890123456';
	
	/*printf("iv: %s\n",bin2hex($iv));
	printf("key256: %s\n",bin2hex($key256));
	printf("key128: %s\n",bin2hex($key128));*/
	
	// This is the plain-text to be encrypted:
	$cleartext = 'The quick brown fox jumped over the lazy dog';
	printf("plainText: %s\n\n",$cleartext);
		
	
	// Now let's do 128-bit encryption:
	if (mcrypt_generic_init($cipher, $key128, $iv) != -1)
	{
		// PHP pads with NULL bytes if $cleartext is not a multiple of the block size..
		$cipherText = mcrypt_generic($cipher,$cleartext );
		mcrypt_generic_deinit($cipher);
		
		// Display the result in hex.
		//printf("128-bit encrypted result:\n%s\n\n",bin2hex($cipherText));
		printf("128-bit encrypted result:\n%s\n\n",$cipherText);
	}
	
	//echo ('<p><a href=test4b.php?param='.bin2hex($cipherText).'>Clickme</a></p>');
	echo ('<p><a href=test4b.php?param='.$cipherText.'>Clickme</a></p>');
?>

Y en test4b lo siguiente:

Código:

<?php	
	$cipher = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', MCRYPT_MODE_CBC, '');
	$encryptedData = $_GET['param'];
	// How do you do 256-bit AES encryption in PHP vs. 128-bit AES encryption???
	// The answer is:  Give it a key that's 32 bytes long as opposed to 16 bytes long.
	// For example:
	$key128 = '1234567890123456';
	
	// Here's our 128-bit IV which is used for both 256-bit and 128-bit keys.
	$iv =  '1234567890123456';
	
	/*printf("iv: %s\n",bin2hex($iv));
	printf("key128: %s\n",bin2hex($key128));*/
	
	/* Reinitialize buffers for decryption */
    mcrypt_generic_init($cipher, $key128, $iv);
    $p_t = mdecrypt_generic($cipher, $encryptedData);

    /* Clean up */
    mcrypt_generic_deinit($cipher);
    mcrypt_module_close($cipher);
	
	//print_r("DEC: ".bin2hex($p_t));
	print_r("DEC: ".$p_t);
	
?>

Alguna idea??