PHP加密解密

//加密
function string2secret($str) 
{ 
 $key = "123"; 
 $td = mcrypt_module_open(MCRYPT_DES,'','ecb',''); 
 $iv = mcrypt_create_iv(mcrypt_enc_get_iv_size($td), MCRYPT_RAND); 
 $ks = mcrypt_enc_get_key_size($td); 
 
 $key = substr(md5($key), 0, $ks); 
 mcrypt_generic_init($td, $key, $iv); 
 $secret = mcrypt_generic($td, $str); 
 mcrypt_generic_deinit($td); 
 mcrypt_module_close($td); 
 return $secret; 
} 
 
//解密 
function secret2string($sec) 
{ 
 $key = "123"; 
 $td = mcrypt_module_open(MCRYPT_DES,'','ecb',''); 
 $iv = mcrypt_create_iv(mcrypt_enc_get_iv_size($td), MCRYPT_RAND); 
 $ks = mcrypt_enc_get_key_size($td); 
 
 $key = substr(md5($key), 0, $ks); 
 mcrypt_generic_init($td, $key, $iv); 
 $string = mdecrypt_generic($td, $sec); 
 mcrypt_generic_deinit($td); 
 mcrypt_module_close($td); 
 return trim($string); 
} 
 
echo secret2string(string2secret("11111111111111111"));   //顯示結果是11111111111111111 

echo '<br>'.string2secret("11111111111111111");    //顯示亂碼 
echo '<br>';

//$string:要加密的字串  $isEncrypt=true:加密 $isEncrypt=false:解密 
function dencrypt($string, $isEncrypt = true, $key = "KEY_SPACE") { 
    if (!isset($string{0}) || !isset($key{0})) { 
        return false; 
    } 
     
    $dynKey = $isEncrypt ? hash('sha1', microtime(true)) : substr($string, 0, 40); 

    $fixedKey = hash('sha1', $key); 
     
    $dynKeyPart1 = substr($dynKey, 0, 20); 
    $dynKeyPart2 = substr($dynKey, 20); 
    $fixedKeyPart1 = substr($fixedKey, 0, 20); 
    $fixedKeyPart2 = substr($fixedKey, 20); 
    $key = hash('sha1', $dynKeyPart1 . $fixedKeyPart1 . $dynKeyPart2 . $fixedKeyPart2); 

     
    $string = $isEncrypt ? $fixedKeyPart1 . $string . $dynKeyPart2 : (isset($string{339}) ? gzuncompress(base64_decode(substr($string, 40))) : base64_decode(substr($string, 40))); 

     
    $n = 0; 
    $result = ''; 
    $len = strlen($string); 
     
    for ($n = 0; $n < $len; $n++) { 
        $result .= chr(ord($string{$n}) ^ ord($key{$n % 40})); 
    } 
    return $isEncrypt ? $dynKey . str_replace('=', '', base64_encode($n > 299 ? gzcompress($result) : $result)) : substr($result, 20, -20); 

} 
echo strlen(dencrypt("12345678912345"));