Шифрование симметричным ключом RSA c#(CryptoAPI)

using System;
using System.Security.Cryptography;
using System.Text;

namespace Lab04_cryptoAPI_
{
    class RSACSPSample
    {

        static void Main()
        {
            Console.WriteLine("Введите строку для шифрования:");
            var original = Console.ReadLine();
            var dataToEncrypt = Encoding.Unicode.GetBytes(original);

            try
            {
                using (RSACryptoServiceProvider RSA = new RSACryptoServiceProvider())
                {

                    //Pass the data to ENCRYPT, the public key information
                    //(using RSACryptoServiceProvider.ExportParameters(false),
                    //and a boolean flag specifying no OAEP padding.
                    var encryptedData = RSAEncrypt(dataToEncrypt, RSA.ExportParameters(false), false);

                    Console.WriteLine($"Зашифрованное сообщение: {Encoding.Unicode.GetString(encryptedData)}");

                    //Pass the data to DECRYPT, the private key information
                    //(using RSACryptoServiceProvider.ExportParameters(true),
                    //and a boolean flag specifying no OAEP padding.
                    var decryptedData = RSADecrypt(encryptedData, RSA.ExportParameters(true), false);

                    //Display the decrypted plaintext to the console.
                    Console.WriteLine($"Рвсшифрованное сообщение: {Encoding.Unicode.GetString(decryptedData)}");
                }
            }
            catch (ArgumentNullException)
            {
                //Catch this exception in case the encryption did
                //not succeed.
                Console.WriteLine("Encryption failed.");

            }
        }

        static public byte[] RSAEncrypt(byte[] DataToEncrypt, RSAParameters RSAKeyInfo, bool DoOAEPPadding)
        {
            try
            {
                byte[] encryptedData;
                //Create a new instance of RSACryptoServiceProvider.
                using (RSACryptoServiceProvider RSA = new RSACryptoServiceProvider())
                {

                    //Import the RSA Key information. This only needs
                    //toinclude the public key information.
                    RSA.ImportParameters(RSAKeyInfo);

                    //Encrypt the passed byte array and specify OAEP padding.
                    //OAEP padding is only available on Microsoft Windows XP or
                    //later.
                    encryptedData = RSA.Encrypt(DataToEncrypt, DoOAEPPadding);
                }
                return encryptedData;
            }
            //Catch and display a CryptographicException
            //to the console.
            catch (CryptographicException e)
            {
                Console.WriteLine(e.Message);

                return null;
            }

        }

        static public byte[] RSADecrypt(byte[] DataToDecrypt, RSAParameters RSAKeyInfo, bool DoOAEPPadding)
        {
            try
            {
                byte[] decryptedData;
                //Create a new instance of RSACryptoServiceProvider.
                using (RSACryptoServiceProvider RSA = new RSACryptoServiceProvider())
                {
                    //Import the RSA Key information. This needs
                    //to include the private key information.
                    RSA.ImportParameters(RSAKeyInfo);

                    //Decrypt the passed byte array and specify OAEP padding.
                    //OAEP padding is only available on Microsoft Windows XP or
                    //later.
                    decryptedData = RSA.Decrypt(DataToDecrypt, DoOAEPPadding);
                }
                return decryptedData;
            }
            //Catch and display a CryptographicException
            //to the console.
            catch (CryptographicException e)
            {
                Console.WriteLine(e.ToString());

                return null;
            }

        }
    }

}