using System.Security.Cryptography;

using System.IO;

using System.Text;

using System;

​

public class Program

{

     private const int keysize = 256;

        //  private const string initVector = "52661318";

            private const string password="32461312";

            private const string text= "<root><user NTID='3344-000001' Timestamp='2019 Aug 08 13:42:53' /></root>";

    public static void Main()

    {

         SHA256 mySHA256 = SHA256Managed.Create();

         byte[] key = mySHA256.ComputeHash(Encoding.ASCII.GetBytes(password));

         byte[] iv = new byte[16] { 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0 };

​

         string encrypted = EncryptString(text, key, iv);

         string decrypted = DecryptString(encrypted, key, iv);

         Console.WriteLine(encrypted);

         Console.WriteLine(decrypted);

    }

public static  string EncryptString(string plainText, byte[] key, byte[] iv)

{

    // Instantiate a new Aes object to perform string symmetric encryption

    Aes encryptor = Aes.Create();

​

    encryptor.Mode = CipherMode.CBC;

​

    // Set key and IV

    byte[] aesKey = new byte[32];

    Array.Copy(key, 0, aesKey, 0, 32);

    encryptor.Key = aesKey;

    encryptor.IV = iv;

​

    // Instantiate a new MemoryStream object to contain the encrypted bytes

    MemoryStream memoryStream = new MemoryStream();

​

    // Instantiate a new encryptor from our Aes object

    ICryptoTransform aesEncryptor = encryptor.CreateEncryptor();

​

    // Instantiate a new CryptoStream object to process the data and write it to the 

    // memory stream

    CryptoStream cryptoStream = new CryptoStream(memoryStream, aesEncryptor, CryptoStreamMode.Write);

​

    // Convert the plainText string into a byte array

    byte[] plainBytes = Encoding.ASCII.GetBytes(plainText);

​

    // Encrypt the input plaintext string

    cryptoStream.Write(plainBytes, 0, plainBytes.Length);

​

    // Complete the encryption process

    cryptoStream.FlushFinalBlock();

​

    // Convert the encrypted data from a MemoryStream to a byte array

    byte[] cipherBytes = memoryStream.ToArray();

​

    // Close both the MemoryStream and the CryptoStream

    memoryStream.Close();

    cryptoStream.Close();

​

    // Convert the encrypted byte array to a base64 encoded string

    string cipherText = Convert.ToBase64String(cipherBytes, 0, cipherBytes.Length);

​

    // Return the encrypted data as a string

    return cipherText;

}

     public static string DecryptString(string cipherText, byte[] key, byte[] iv)

{

    // Instantiate a new Aes object to perform string symmetric encryption

    Aes encryptor = Aes.Create();

​

    encryptor.Mode = CipherMode.CBC;

​

    // Set key and IV

    byte[] aesKey = new byte[32];

    Array.Copy(key, 0, aesKey, 0, 32);

    encryptor.Key = aesKey;

    encryptor.IV = iv;

​

    // Instantiate a new MemoryStream object to contain the encrypted bytes

    MemoryStream memoryStream = new MemoryStream();

​

    // Instantiate a new encryptor from our Aes object

    ICryptoTransform aesDecryptor = encryptor.CreateDecryptor();

​

    // Instantiate a new CryptoStream object to process the data and write it to the 

    // memory stream

    CryptoStream cryptoStream = new CryptoStream(memoryStream, aesDecryptor, CryptoStreamMode.Write);

​

    // Will contain decrypted plaintext

    string plainText = String.Empty;

​

    try {

        // Convert the ciphertext string into a byte array

        byte[] cipherBytes = Convert.FromBase64String(cipherText);

​

        // Decrypt the input ciphertext string

        cryptoStream.Write(cipherBytes, 0, cipherBytes . Length);

​

        // Complete the decryption process

        cryptoStream.FlushFinalBlock();

​

        // Convert the decrypted data from a MemoryStream to a byte array

        byte[] plainBytes = memoryStream.ToArray();

​

        // Convert the decrypted byte array to string

        plainText = Encoding.ASCII.GetString(plainBytes, 0, plainBytes.Length);

    } finally {

        // Close both the MemoryStream and the CryptoStream

        memoryStream.Close();

        cryptoStream.Close();

    }

​

    // Return the decrypted data as a string

    return plainText;

}

}