using System;

using System.IO;

using System.Security.Cryptography;

using System.Text;

​

public class Program

{

    public static void Main()

    {

        string message = "My secret message 1234";

        string password = "3d756227f8be6f85";

        string ivstr = "ba7e0bb79b61f82d";  

        Program p=new Program();

​

        string encrypted = p.EncryptString(message, password, ivstr);

        string decrypted = p.DecryptString(encrypted, password, ivstr);

​

        Console.WriteLine(encrypted);

        Console.WriteLine(decrypted);

    }

    public  string EncryptString(string plainText, string password,string ivstr)

    {

         byte[] key = Encoding.UTF8.GetBytes(password);

         byte[] iv = Encoding.UTF8.GetBytes(ivstr);

        // 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[16];

        Array.Copy(key, 0, aesKey, 0, 16);

        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  string DecryptString(string cipherText,  string password,string ivstr)

    {

         byte[] key = Encoding.UTF8.GetBytes(password);

         byte[] iv = Encoding.UTF8.GetBytes(ivstr);

        // 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[16];

        Array.Copy(key, 0, aesKey, 0, 16);

        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;

    }

}