/**
 * 
 * 加密函数
 * 算法：des
 * 加密模式：ecb
 * 补齐方法：PKCS5
 * 
 * @param unknown_type $input
 */
function encryptDesEcbPKCS5($input, $key) 
{ 
    $size = mcrypt_get_block_size('des', 'ecb'); 
    $input = pkcs5_pad($input, $size); 
    
    $td = mcrypt_module_open('des', '', 'ecb', ''); 
    //$iv = mcrypt_create_iv (mcrypt_enc_get_iv_size($td), MCRYPT_RAND); 
    $iv = 0;
    mcrypt_generic_init($td, $key, $iv); 
    $data = mdecrypt_generic ($td, $input); 
    mcrypt_generic_deinit($td); 
    mcrypt_module_close($td); 
    //$data = base64_encode($data); 
    return $data; 
} 

/**
 * 解密函数
 * 算法：des
 * 加密模式：ecb
 * 补齐方法：PKCS5
 * @param unknown_type $input
 */
function decryptDesEcbPKCS5($input, $key) 
{ 
    $size = mcrypt_get_block_size('des', 'ecb'); 
   
    $td = mcrypt_module_open('des', '', 'ecb', ''); 
    $iv = 0;
    mcrypt_generic_init($td, $key, $iv); 
    $data = mcrypt_generic($td, $input); 
    mcrypt_generic_deinit($td); 
    mcrypt_module_close($td); 
    $data = pkcs5_unpad($data, $size); 
    //$data = base64_encode($data); 
    return $data; 
} 

function pkcs5_pad ($text, $blocksize) 
{ 
    $pad = $blocksize - (strlen($text) % $blocksize); 
    return $text . str_repeat(chr($pad), $pad); 
} 

function pkcs5_unpad($text) 
{ 
    $pad = ord($text{strlen($text) - 1}); 
    if ($pad > strlen($text)) 
    	return false; 
    if (strspn($text, chr($pad), strlen($text) - $pad) != $pad) 
    	return false; 
    return substr($text, 0, -1 * $pad); 
} 

$str = 'test crypt';
$key = 'jack11';
$res = encryptDesEcbPKCS5($str, $key);
echo "$res\n";


$deRes = decryptDesEcbPKCS5($res, $key);

echo "\n$deRes\n";

?

PHP的ＤＥＳ加密的补齐比较特殊，而且不能指定

http://www.herongyang.com/Cryptography/DES-PHP-Block-Padding-in-mcrypt.html