MARKUS

using System;

using System.Collections.Generic;

using System.Linq;

using System.Security.Cryptography;

using System.Text;

using System.Threading.Tasks;

namespace ConnectionStrEncrypt

{

    class Program

    {

        static void Main(string[] args)

        {

            Restart:

            string connection;

            string value;

            string key = "Doftech1073#";

            Console.WriteLine("ex) data source=address;database=database;user id=userid;password=password");

            Console.Write("input Connection String : ");

            connection = Console.ReadLine();

            SelectEncrypt:

            Console.WriteLine("1.Encrypt 2.Decrypt");

            Console.Write("Input 1 or 2 :");

            value = Console.ReadLine().Trim();

            if(value != "1" && value != "2")

            {

                Console.WriteLine("Try again");

                goto SelectEncrypt;

            }

            else if(value == "1")

            {

                Console.WriteLine("Encrypt Connection String -");

                Console.WriteLine(Encrypt(connection, key));

            }

            else

            {

                Console.WriteLine("Decrypt Connection String -");

                Console.WriteLine(Decrypt(connection, key));

            }

            goto Restart;

        }

        public static string Decrypt(string textToDecrypt, string key)

        {

            RijndaelManaged rijndaelCipher = new RijndaelManaged();

            rijndaelCipher.Mode = CipherMode.CBC;

            rijndaelCipher.Padding = PaddingMode.PKCS7;

            rijndaelCipher.KeySize = 128;

            rijndaelCipher.BlockSize = 128;

            byte[] encryptedData = Convert.FromBase64String(textToDecrypt);

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

            byte[] keyBytes = new byte[16];

            int len = pwdBytes.Length;

            if (len > keyBytes.Length)

            {

                len = keyBytes.Length;

            }

            Array.Copy(pwdBytes, keyBytes, len);

            rijndaelCipher.Key = keyBytes;

            rijndaelCipher.IV = keyBytes;

            byte[] plainText = rijndaelCipher.CreateDecryptor().TransformFinalBlock(encryptedData, 0, encryptedData.Length);

            return Encoding.UTF8.GetString(plainText);

        }

        public static string Encrypt(string textToEncrypt, string key)

        {

            RijndaelManaged rijndaelCipher = new RijndaelManaged();

            rijndaelCipher.Mode = CipherMode.CBC;

            rijndaelCipher.Padding = PaddingMode.PKCS7;

            rijndaelCipher.KeySize = 128;

            rijndaelCipher.BlockSize = 128;

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

            byte[] keyBytes = new byte[16];

            int len = pwdBytes.Length;

            if (len > keyBytes.Length)

            {

                len = keyBytes.Length;

            }

            Array.Copy(pwdBytes, keyBytes, len);

            rijndaelCipher.Key = keyBytes;

            rijndaelCipher.IV = keyBytes;

            ICryptoTransform transform = rijndaelCipher.CreateEncryptor();

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

            return Convert.ToBase64String(transform.TransformFinalBlock(plainText, 0, plainText.Length));

        }

    }

}