Как использовать ключ RSA в AES шифрование?

Никак не могу сообразить как мне правильно сделать реализацию чтобы впихнуть ключ RSA 2048 в шифрование AES.

У меня есть этот метод AES шифрования:

public static void AES_Encrypt(string inputFile, string password)
{
            try
            {
                byte[] passBytes = Encoding.UTF8.GetBytes(password);
                byte[] saltBytes = new byte[12];
                using (MemoryStream tempStream = new MemoryStream())
                {
                    using (var inputFileStream = new FileStream(inputFile, FileMode.Open))
                        inputFileStream.CopyTo(tempStream);
                    tempStream.Position = 0;
                    using (var outFileStream = new FileStream(inputFile, FileMode.Create))
                    using (var rijndaelManaged = new RijndaelManaged())
                    {
                        rijndaelManaged.KeySize = 256;
                        rijndaelManaged.BlockSize = 128;
                        using (var rfc2898DeriveBytes = new Rfc2898DeriveBytes(passBytes, saltBytes, 1000))
                        {
                            rijndaelManaged.Key = rfc2898DeriveBytes.GetBytes(rijndaelManaged.KeySize / 8);
                            rijndaelManaged.IV = rfc2898DeriveBytes.GetBytes(rijndaelManaged.BlockSize / 8);
                        }
                        rijndaelManaged.Mode = CipherMode.CBC;
                        using (var cryptoStream = new CryptoStream(outFileStream, rijndaelManaged.CreateEncryptor(), CryptoStreamMode.Write))
                        {
                            tempStream.CopyTo(cryptoStream);
                        }
                    }
                }
            }
            catch (CryptographicException ex) { File.AppendAllText("AES_Enc.txt", ex.Message + "\r\n" + ex.ToString()); }
            catch (IOException ex) { File.AppendAllText("AES_Enc_IO.txt", ex.Message + "\r\n" + ex.ToString()); }
            catch (UnauthorizedAccessException) { }
}
public static void AES_Decrypt(string inputFile, string password)
{
            try
            {
                byte[] passBytes = Encoding.UTF8.GetBytes(password);
                byte[] saltBytes = new byte[12];
                using (MemoryStream tempStream = new MemoryStream())
                {
                    using (var inputFileStream = new FileStream(inputFile, FileMode.Open))
                        inputFileStream.CopyTo(tempStream);
                    tempStream.Position = 0;
                    using (var outFileStream = new FileStream(inputFile, FileMode.Create))
                    using (var rijndaelManaged = new RijndaelManaged())
                    {
                        rijndaelManaged.KeySize = 256;
                        rijndaelManaged.BlockSize = 128;
                        using (var rfc2898DeriveBytes = new Rfc2898DeriveBytes(passBytes, saltBytes, 1000))
                        {
                            rijndaelManaged.Key = rfc2898DeriveBytes.GetBytes(rijndaelManaged.KeySize / 8);
                            rijndaelManaged.IV = rfc2898DeriveBytes.GetBytes(rijndaelManaged.BlockSize / 8);
                        }
                        rijndaelManaged.Mode = CipherMode.CBC;
                        using (var cryptoStream = new CryptoStream(tempStream, rijndaelManaged.CreateDecryptor(), CryptoStreamMode.Read))
                        {
                            cryptoStream.CopyTo(outFileStream);
                        }
                    }
                }
            }
            catch (CryptographicException ex) { File.AppendAllText("AES_Enc.txt", ex.Message + "\r\n" + ex.ToString()); }
            catch (IOException ex) { File.AppendAllText("AES_Enc_IO.txt", ex.Message + "\r\n" + ex.ToString()); }
            catch (UnauthorizedAccessException) { }
}

У меня так же имеется публичный и приватный ключ который я получаю :

public string GetKey(bool choice)
{
    string key = null;
    try
    {
         using (RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(2048))
         {
                    if (choice) 
                    { 
                       key = rsa.ToXmlString(false);
                    }
                    else 
                    { 
                       key = rsa.ToXmlString(true); 
                    }
                }
            }
            catch (CryptographicException) { }
            return key;
 }

Как мне применить полученный ключ RSA-2048 к AES ( для шифрования aes ключа ) ?