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

class ManagedAesSample
{
    public static void Main()
    {
        Console.WriteLine("Enter text that needs to be encrypted..");
        string data = Console.ReadLine();
        EncryptAesManaged(data);
        Console.ReadLine();
    }
    static void EncryptAesManaged(string raw)
    {
        try
        {
            // Create Aes that generates a new key and initialization vector (IV).
            // Same key must be used in encryption and decryption
            byte[] IV;
            byte[] key = Encoding.UTF8.GetBytes("123");
            MD5 md5 = new MD5CryptoServiceProvider();
            IV = md5.ComputeHash(key);
            byte[] Key;
            SHA256 shaM = new SHA256Managed();
            Key = shaM.ComputeHash(key);

            using (AesManaged aes = new AesManaged())
            {
                // Encrypt string
                byte[] encrypted = Encrypt(raw, Key, IV);
                // Print encrypted string
                Console.WriteLine($"Encrypted data: {System.Text.Encoding.UTF8.GetString(encrypted)}");
                // Decrypt the bytes to a string.
                string decrypted = Decrypt(encrypted, Key, IV);
                // Print decrypted string. It should be same as raw data
                Console.WriteLine($"Decrypted data: {decrypted}");
            }
        }
        catch (Exception exp)
        {
            Console.WriteLine(exp.Message);
        }
        Console.ReadKey();
    }
    static byte[] Encrypt(string plainText, byte[] Key, byte[] IV)
    {
        byte[] encrypted;
        // Create a new AesManaged.
        using (AesManaged aes = new AesManaged())
        {
            // Create encryptor
            ICryptoTransform encryptor = aes.CreateEncryptor(Key, IV);
            // Create MemoryStream
            using (MemoryStream ms = new MemoryStream())
            {
                // Create crypto stream using the CryptoStream class. This class is the key to encryption
                // and encrypts and decrypts data from any given stream. In this case, we will pass a memory stream
                // to encrypt
                using (CryptoStream cs = new CryptoStream(ms, encryptor, CryptoStreamMode.Write))
                {
                    // Create StreamWriter and write data to a stream
                    using (StreamWriter sw = new StreamWriter(cs))
                        sw.Write(plainText);
                    encrypted = ms.ToArray();
                }
            }
        }
        // Return encrypted data
        return encrypted;
    }
    static string Decrypt(byte[] cipherText, byte[] Key, byte[] IV)
    {
        string plaintext = null;
        // Create AesManaged
        using (AesManaged aes = new AesManaged())
        {
            // Create a decryptor
            ICryptoTransform decryptor = aes.CreateDecryptor(Key, IV);
            // Create the streams used for decryption.
            using (MemoryStream ms = new MemoryStream(cipherText))
            {
                // Create crypto stream
                using (CryptoStream cs = new CryptoStream(ms, decryptor, CryptoStreamMode.Read))
                {
                    // Read crypto stream
                    using (StreamReader reader = new StreamReader(cs))
                        plaintext = reader.ReadToEnd();
                }
            }
        }
        return plaintext;
    }
}