目前我正在使用

$key="pass";
$val="secret";
$encp=mcrypt_encrypt(MCRYPT_DES, $key, $val, MCRYPT_MODE_ECB);

但是当我打电话给printf($encp)
没有显示值,使用PHP版本5.2.17

有没有更好的方法.请帮忙.

编辑：

<?PHP

    define('SECURE_KEY','Somekey');

    function encrypt($value){
        $iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB);
        $iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
        return mcrypt_encrypt(MCRYPT_RIJNDAEL_256, SECURE_KEY, $value, MCRYPT_MODE_ECB, $iv);
    }

    function decrypt($value){
        $iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB);
        $iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
        return trim(mcrypt_decrypt(MCRYPT_RIJNDAEL_256, SECURE_KEY, $value, MCRYPT_MODE_ECB, $iv));
    }
    $temp=encrypt("teststring");
    printf($temp);
    ?>

解决方法:

更新(17/09/17)：

从PHP 7.1.0开始不推荐使用mcrypt_encrypt.香港专业教育学院增加了一个简单的加密/解密使用openssl.

function encrypt($string, $key = 'PrivateKey', $secret = 'SecretKey', $method = 'AES-256-CBC') {
    // hash
    $key = hash('sha256', $key);
    // create iv - encrypt method AES-256-CBC expects 16 bytes
    $iv = substr(hash('sha256', $secret), 0, 16);
    // encrypt
    $output = openssl_encrypt($string, $method, $key, 0, $iv);
    // encode
    return base64_encode($output);
}

function decrypt($string, $key = 'PrivateKey', $secret = 'SecretKey', $method = 'AES-256-CBC') {
    // hash
    $key = hash('sha256', $key);
    // create iv - encrypt method AES-256-CBC expects 16 bytes
    $iv = substr(hash('sha256', $secret), 0, 16);
    // decode
    $string = base64_decode($string);
    // decrypt
    return openssl_decrypt($string, $method, $key, 0, $iv);
}

$str = 'Encrypt this text';
echo "Plain: " .$str. "\n";

// encrypt
$encrypted_str = encrypt($str);
echo "Encrypted: " .$encrypted_str. "\n";

// decrypt
$decrypted_str = decrypt($encrypted_str);
echo "Decrypted: " .$decrypted_str. "\n";

尝试以下操作：(PHP< 7.1.0)如果您使用> PHP 7.1.0参见上文.

define('SECURE_KEY','Somekey');//Assigned within a config, pref outside of root dir

function encrypt($value){
    $iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB);
    $iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
    return mcrypt_encrypt(MCRYPT_RIJNDAEL_256, SECURE_KEY, $value, MCRYPT_MODE_ECB, $iv);
}

function decrypt($value){
    $iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB);
    $iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
    return trim(mcrypt_decrypt(MCRYPT_RIJNDAEL_256, SECURE_KEY, $value, MCRYPT_MODE_ECB, $iv));
}
//Simple usage
$encryptedString = encrypt('This String Will Be encrypted');
echo decrypt($encryptedString);

从源代码编辑-http://php.net/manual/en/function.mcrypt-encrypt.php