using System;

using System.Collections.Generic;

using System.IO;

using System.Linq;

using System.Security.Cryptography;

using System.Text;

using System.Threading.Tasks;

public class Program

{

    public static void Main()

        {

            string key = "71384";

            string text = "data";

​

            string Encrypt = NewMethod(key, text);

            string Decrypt = NewMethod(key, Encrypt);

​

            Console.WriteLine(text);

            Console.WriteLine(Encrypt);

            Console.WriteLine(Decrypt);

        }

​

        private static string NewMethod(string key, string text)

        {

            RijndaelManaged AesEncryption = new RijndaelManaged();

            AesEncryption.KeySize = 256;

            AesEncryption.BlockSize = 128;

            AesEncryption.Mode = CipherMode.CBC;

            AesEncryption.Padding = PaddingMode.PKCS7;

            AesEncryption.Key = GetByteKey(key);

            ICryptoTransform crypto = AesEncryption.CreateEncryptor();

​

            var plainText = ASCIIEncoding.UTF8.GetBytes(text);

            var encrypted = crypto.TransformFinalBlock(plainText, 0, plainText.Length);

            string dataStr = Convert.ToBase64String(encrypted);

            return dataStr;

        }

        private static string NewMethod2(string key, string dataStr)

        {

            RijndaelManaged AesEncryption = new RijndaelManaged();

            AesEncryption.KeySize = 256;

            AesEncryption.BlockSize = 128;

            AesEncryption.Mode = CipherMode.CBC;

            AesEncryption.Padding = PaddingMode.PKCS7;

            AesEncryption.Key = GetByteKey(key);

​

            //Decrypt

            string encryptedData = dataStr;

            ICryptoTransform decryptor = AesEncryption.CreateDecryptor();

            var encrypted = Convert.FromBase64String(encryptedData);

            string text = ASCIIEncoding.UTF8.GetString(decryptor.TransformFinalBlock(encrypted, 0, encrypted.Length));

            return text;

        }

        public static byte[] GetByteKey(string input)

        {

            using (MD5 md5Hash = MD5.Create())

            {

                // Convert the input string to a byte array and compute the hash.

                byte[] data = md5Hash.ComputeHash(Encoding.UTF8.GetBytes(input));

​

                // Create a new Stringbuilder to collect the bytes

                // and create a string.

                StringBuilder sBuilder = new StringBuilder();

​

                // Loop through each byte of the hashed data 

                // and format each one as a hexadecimal string.

                for (int i = 0; i < data.Length; i++)

                {

                    sBuilder.Append(data[i].ToString("x2"));

                }

​

                byte[] bytes = Encoding.ASCII.GetBytes(sBuilder.ToString());

                // Return the hexadecimal string.

                return bytes.Take(16).ToArray();

            }

        }

}