using System;

using System.IO;

using System.Security.Cryptography;

using System.Text;

​

namespace Test

{

    public class EncriptionHelper

    {   

            public static void Main()

            {

                var cleanTxt = "8212093345";

                var encTxt = "EAAAADE2ODA2NjQya2JNN2M1ISShgi+Oi5tbsPgOz5KsCHj0";

                var secret = "KJH#$@kds32@!kjhdkftt";

                var xtxt =  EncryptStringAES(cleanTxt, secret);             

                var txt =   DecryptStringAES(encTxt, secret);

                Console.WriteLine(txt);

                Console.WriteLine(xtxt);

            }

        private static byte[] vector = Encoding.ASCII.GetBytes("16806642kbM7c5!$");

        private static byte[] salt = new byte[] { 34, 134, 145, 12, 7, 6, 243, 63, 43, 54, 75, 65, 53, 2, 34, 54, 45, 67, 64, 64, 32, 213 };

        /// <summary>

        /// Encrypt the given string using AES.  The string can be decrypted using 

        /// DecryptStringAES().  The sharedSecret parameters must match.

        public static string EncryptStringAES(string text, string sharedSecret)

        {

            if (string.IsNullOrEmpty(text))

            {

                throw new ArgumentNullException("Text is null or empty");

            }

​

            if (string.IsNullOrEmpty(sharedSecret))

            {

                throw new ArgumentNullException("Secret is null or empty");

            }

​

            if (salt == null || salt.Length == 0)

            {

                throw new ArgumentNullException("Salt is null or empty");

            }

​

            string outStr = null;

            RijndaelManaged aesAlg = null;

            try

            {

                Rfc2898DeriveBytes key = new Rfc2898DeriveBytes(sharedSecret, salt);

​

                aesAlg = new RijndaelManaged();

                aesAlg.Key = key.GetBytes(aesAlg.KeySize / 8);

                aesAlg.IV = vector;

​

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

                using (MemoryStream msEncrypt = new MemoryStream())

                {

                    msEncrypt.Write(BitConverter.GetBytes(aesAlg.IV.Length), 0, sizeof(int));

                    msEncrypt.Write(aesAlg.IV, 0, aesAlg.IV.Length);

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

                    {

                        using (StreamWriter swEncrypt = new StreamWriter(csEncrypt))

                        {

                            swEncrypt.Write(text);

                        }

                    }

                    outStr = Convert.ToBase64String(msEncrypt.ToArray());

                }

            }

            finally

            {

                // Clear the RijndaelManaged object.

                if (aesAlg != null)

                    aesAlg.Clear();

            }

​

            // Return the encrypted bytes from the memory stream.

            return outStr;

        }

​

        /// <summary>

        /// Decrypt the given string.  Assumes the string was encrypted using 

        /// EncryptStringAES(), using an identical sharedSecret.

        /// </summary>

        public static string DecryptStringAES(string cipherText, string sharedSecret)

        {

            if (string.IsNullOrEmpty(cipherText))

            {

                throw new ArgumentNullException("Text is null or empty");

            }

​

            if (string.IsNullOrEmpty(sharedSecret))

            {

                throw new ArgumentNullException("Secret is null or empty");

            }

​

            if (salt == null || salt.Length == 0)

            {

                throw new ArgumentNullException("Salt is null or empty");

            }

​

            RijndaelManaged aesAlg = null;

            string result = null;

​

            try

            {

                Rfc2898DeriveBytes key = new Rfc2898DeriveBytes(sharedSecret, salt);

                byte[] bytes = Convert.FromBase64String(cipherText);

                using (MemoryStream msDecrypt = new MemoryStream(bytes))

                {

                    aesAlg = new RijndaelManaged();

                    aesAlg.Key = key.GetBytes(aesAlg.KeySize / 8);

                    aesAlg.IV = ReadByteArray(msDecrypt);

                    Console.WriteLine("KEY: "+ Convert.ToBase64String(aesAlg.Key));

                    Console.WriteLine("IV: "+ Convert.ToBase64String(aesAlg.IV));

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

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

                    {

                        using (StreamReader srDecrypt = new StreamReader(csDecrypt))

                        {

                            result = srDecrypt.ReadToEnd();

                        }

                    }

                }

            }

            finally

            {

                // Clear the RijndaelManaged object.

                if (aesAlg != null)

                    aesAlg.Clear();

            }

​

            return result;

        }

​

        private static byte[] ReadByteArray(Stream s)

        {

            byte[] rawLength = new byte[sizeof(int)];

            if (s.Read(rawLength, 0, rawLength.Length) != rawLength.Length)

            {

                throw new SystemException("Stream did not contain properly formatted byte array");

            }

​

            byte[] buffer = new byte[BitConverter.ToInt32(rawLength, 0)];

            if (s.Read(buffer, 0, buffer.Length) != buffer.Length)

            {

                throw new SystemException("Did not read byte array properly");

            }

​

            return buffer;

        }

​

    }

}