using System;

using System.Security.Cryptography;

using System.Text;

​

public class Program

{

    public static void Main()

    {

        var encrypt = EncryptString("Server=localhost\\SQLEXPRESS;Database=DynamicCommandExecutor;User Id=sa;Password=xxxx;TrustServerCertificate=True;","connectionstring");

        Console.WriteLine(encrypt);

        Console.WriteLine(DecryptString(encrypt,"connectionstring"));

    }

      public static string EncryptString(string plainText, string key)

      {

​

          using (Aes aes = Aes.Create())

          {

              aes.Key = CreateKey(key);

              aes.Mode = CipherMode.ECB;

              aes.Padding = PaddingMode.PKCS7;

​

              ICryptoTransform encryptor = aes.CreateEncryptor();

              byte[] inputBytes = Encoding.UTF8.GetBytes(plainText);

              byte[] encryptedBytes = encryptor.TransformFinalBlock(inputBytes, 0, inputBytes.Length);

​

              return Convert.ToBase64String(encryptedBytes).Replace('+','-').Replace('/','_');

          }

      }

​

      public static string DecryptString( string cipherText, string key)

      {

          using (Aes aes = Aes.Create())

          {

              aes.Key = CreateKey(key);

              aes.Mode = CipherMode.ECB;

              aes.Padding = PaddingMode.PKCS7;

​

              ICryptoTransform decryptor = aes.CreateDecryptor();

              byte[] cipherBytes = Convert.FromBase64String(cipherText.Replace('-', '+').Replace('_', '/'));

              byte[] decryptedBytes = decryptor.TransformFinalBlock(cipherBytes, 0, cipherBytes.Length);

​

              return Encoding.UTF8.GetString(decryptedBytes);

          }

      }

​

      static byte[] CreateKey(string key)

      {

          using (SHA256 sha256 = SHA256.Create())

          {

              return sha256.ComputeHash(Encoding.UTF8.GetBytes(key));

          }

      }

}