using System.IO;

using System.Security.Cryptography;

using System.Text;

using System;

public class Program

{

    public static void Main()

    {

         byte[] ct = Encrypt(123456, "The quick brown fox jumps over the lazy dog45678", 7890);

         string dt = Decrypt(123456, ct, 7890);

         Console.WriteLine(dt);

    }

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

     {

         byte[] encryptedText;

         Aes aesAlg = Aes.Create();

         string keyString = key.ToString();

         Rfc2898DeriveBytes sourceDeriveBytes = new(keyString, Encoding.UTF8.GetBytes(keyString));

         byte[] keyBytes = sourceDeriveBytes.GetBytes(16);

         aesAlg.Key = keyBytes;

​

         string ivString = iv.ToString();

         Rfc2898DeriveBytes zendeskDeriveBytes = new(ivString, Encoding.UTF8.GetBytes(ivString));

         byte[] ivBytes = zendeskDeriveBytes.GetBytes(16);

         aesAlg.IV = ivBytes;

​

         aesAlg.Padding = PaddingMode.None;

​

         ICryptoTransform encryptor = aesAlg.CreateEncryptor(aesAlg.Key, aesAlg.IV);

         using (MemoryStream msEncrypt = new MemoryStream())

         {

             using (CryptoStream csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))

             {

                 using (StreamWriter swEncrypt = new StreamWriter(csEncrypt))

                 {

                     swEncrypt.Write(plainText);

                 }

             }

             encryptedText = msEncrypt.ToArray();

​

         }

​

         return encryptedText;

     }

​

     public static string Decrypt(int key, byte[] encryptedText, int iv)

     {

         string plainText;

         Aes aesAlg = Aes.Create();

         string keyString = key.ToString();

         Rfc2898DeriveBytes pbkdf = new(keyString, Encoding.UTF8.GetBytes(keyString));

         byte[] keyBytes = pbkdf.GetBytes(16);

         aesAlg.Key = keyBytes;

​

         string ivString = iv.ToString();

         Rfc2898DeriveBytes zendeskDeriveBytes = new(ivString, Encoding.UTF8.GetBytes(ivString));

         byte[] ivBytes = zendeskDeriveBytes.GetBytes(16);

         aesAlg.IV = ivBytes;

​

         aesAlg.Padding = PaddingMode.None;

​

         ICryptoTransform decryptor = aesAlg.CreateDecryptor(aesAlg.Key, aesAlg.IV);

​

         using (MemoryStream msDecrypt = new MemoryStream(encryptedText))

         {

             using (CryptoStream csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))

             {

                 using (StreamReader srDecrypt = new StreamReader(csDecrypt))

                 {

                     plainText = srDecrypt.ReadToEnd();

                 }

             }

         }

​

         return plainText;

     }

}