Добавление метода в статический класс Program - C#

public string Decrypt(string cipherText, string password, string salt = "Kosher", string hashAlgorithm = "SHA1", int passwordIterations = 2, string initialVector = "OFRna73m*aze01xY", int keySize = 256)
        {
            if (string.IsNullOrEmpty(cipherText))
                return "";
 
            byte[] initialVectorBytes = Encoding.ASCII.GetBytes(initialVector);
            byte[] saltValueBytes = Encoding.ASCII.GetBytes(salt);
            byte[] cipherTextBytes = Convert.FromBase64String(cipherText);
 
            PasswordDeriveBytes derivedPassword = new PasswordDeriveBytes(password, saltValueBytes, hashAlgorithm, passwordIterations);
            byte[] keyBytes = derivedPassword.GetBytes(keySize / 8);
 
            RijndaelManaged symmetricKey = new RijndaelManaged();
            symmetricKey.Mode = CipherMode.CBC;
 
            byte[] plainTextBytes = new byte[cipherTextBytes.Length];
            int byteCount = 0;
 
            using (ICryptoTransform decryptor = symmetricKey.CreateDecryptor(keyBytes, initialVectorBytes))
            {
                using (MemoryStream memStream = new MemoryStream(cipherTextBytes))
                {
                    using (CryptoStream cryptoStream = new CryptoStream(memStream, decryptor, CryptoStreamMode.Read))
                    {
                        byteCount = cryptoStream.Read(plainTextBytes, 0, plainTextBytes.Length);
                        memStream.Close();
                        cryptoStream.Close();
                    }
                }
            }
 
            symmetricKey.Clear();
            return Encoding.UTF8.GetString(plainTextBytes, 0, byteCount);
        }

Decrypt(password, "Passpord11", "Password22", "SHA1", 2, "16CHARSLONG12345", 256)