A problem with an encryption algorithm program written in C#

Question

I wrote a program in .NET 7 that encrypts a string and returns another string that contains the encrypted form of the first string. The problem is the program does not return anything, only a null string

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

internal class Program
{
    private static void Main(string[] args)
    {
        string unencrypted = Console.ReadLine();
        byte[] transformed = Encoding.UTF8.GetBytes(necriptat);
        byte[] encrypted;
        string cipher;

        Aes aes = Aes.Create();
        MemoryStream memoryStream = new MemoryStream();
        ICryptoTransform cryptoTransform = aes.CreateEncryptor(aes.Key, aes.IV);

        CryptoStream cstream = new CryptoStream(memoryStream, cryptoTransform, CryptoStreamMode.Write);
        StreamWriter streamW = new StreamWriter(cstream);
        streamW.Write(transformed);

        encrypted = memoryStream.ToArray();
        cipher = Encoding.UTF8.GetString(encrypted);
        Console.WriteLine(cipher);
    }
}

I want from this program to return a string containing the encrypted form of the first string. I would be thankful if you can help me to fix my problem

Answer 1

You missed synchronizing the buffer:

streamW.Write(transformed);
cstream.FlushFinalBlock(); <-- Here
encrypted = memoryStream.ToArray();