php rsa类的一个写法

class des{
    function encrypt($encrypt,$key) {
        $encrypt =Des::pkcs5_pad($encrypt);
        $iv = mcrypt_create_iv(mcrypt_get_iv_size(MCRYPT_DES, MCRYPT_MODE_ECB), MCRYPT_RAND);
        $passcrypt = mcrypt_encrypt(MCRYPT_DES, $key, $encrypt, MCRYPT_MODE_ECB, $iv);
        return strtoupper(bin2hex($passcrypt));
    }

    function decrypt($decrypt,$key) {
        $decoded = @pack("H*", $decrypt);
        $iv = mcrypt_create_iv(mcrypt_get_iv_size(MCRYPT_DES, MCRYPT_MODE_ECB), MCRYPT_RAND);
        $decrypted = mcrypt_decrypt(MCRYPT_DES,  $key, $decoded, MCRYPT_MODE_ECB, $iv);
        return Des::pkcs5_unpad($decrypted);
    }

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

    function pkcs5_pad($text){
        $len = strlen($text);
        $mod = $len % 8;
        $pad = 8 - $mod;
        return $text.str_repeat(chr($pad),$pad);
    }
}

还需要深入研究下，生成证书啥的