将PHP中的Aes加密转换为c＃

Question

I am trying to convert a php aes encryption logic to c# but not able to make it work as per the server endpoint.

Can any one help in conversion on below php code to c#?

I have tried php to.net migration assistant but it failed near the encryption function.

PHP code:

    class Security
{
    public static function encrypt($input, $key)
    {
        $size = mcrypt_get_block_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_ECB);
        $input = Security::pkcs5_pad($input, $size);
        $td = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', MCRYPT_MODE_ECB, '');
        $iv = mcrypt_create_iv (mcrypt_enc_get_iv_size($td), MCRYPT_RAND);
        mcrypt_generic_init($td, $key, $iv);
        $data = mcrypt_generic($td, $input);
        mcrypt_generic_deinit($td);
        mcrypt_module_close($td);
        // $data = utf8_encode(base64_encode($data));

        $data = base64_encode($data);
        return $data;
    }


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

    public static function decrypt($sStr, $sKey)
    {
        $decrypted= mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $sKey, base64_decode(str_replace(" ","+",$sStr)), MCRYPT_MODE_ECB);
        $dec_s = strlen($decrypted);
        $padding = ord($decrypted[$dec_s-1]);
        $decrypted = substr($decrypted, 0, -$padding);
        return $decrypted;
    }
}

c# code

public static String EncryptJava(String plainText, String key)
        {
            UTF8Encoding UTF8 = new UTF8Encoding();
            AesManaged tdes = new AesManaged();
            tdes.Key = UTF8.GetBytes(key);
            tdes.Mode = CipherMode.ECB;
            tdes.Padding = PaddingMode.PKCS7;
            ICryptoTransform crypt = tdes.CreateEncryptor();
            byte[] plain = Encoding.UTF8.GetBytes(plainText);
            byte[] cipher = crypt.TransformFinalBlock(plain, 0, plain.Length);
            return Convert.ToBase64String(cipher);
        }

Answer 1

The code you want should be:

public static string Encrypt(string plainText, string key)
{
    using (var enc = new RijndaelManaged())
    {
        byte[] key2 = Encoding.UTF8.GetBytes(key);
        // Rijndael supports keys of 16, 24, 32 byte long
        Array.Resize(ref key2, key2.Length <= 16 ? 16 : key2.Length <= 24 ? 24 : 32);
        enc.Key = key2; 
        enc.Mode = CipherMode.ECB;
        enc.Padding = PaddingMode.PKCS7;

        using (ICryptoTransform crypt = enc.CreateEncryptor())
        {
            byte[] plain = Encoding.UTF8.GetBytes(plainText);
            byte[] cipher = crypt.TransformFinalBlock(plain, 0, plain.Length);
            return Convert.ToBase64String(cipher);
        }
    }
}

Note that PHP will select the exact type of Rijnadael (128, 192, 256) based on the key size, padding with \0 the key to length 16, 24, 32.

To decrypt:

public static string Decrypt(string cipherText, string key)
{
    using (var enc = new RijndaelManaged())
    {
        byte[] key2 = Encoding.UTF8.GetBytes(key);
        // Rijndael supports keys of 16, 24, 32 byte long
        Array.Resize(ref key2, key2.Length <= 16 ? 16 : key2.Length <= 24 ? 24 : 32);
        enc.Key = key2;
        enc.Mode = CipherMode.ECB;
        enc.Padding = PaddingMode.PKCS7;

        using (ICryptoTransform crypt = enc.CreateDecryptor())
        {
            byte[] cipher = Convert.FromBase64String(cipherText);
            byte[] plain = crypt.TransformFinalBlock(cipher, 0, cipher.Length);
            return Encoding.UTF8.GetString(plain);
        }
    }
}