using System;

using System.Collections.Generic;

using System.Linq;

using System.Text.RegularExpressions;

using System.Text;

using System.Security.Cryptography;

using System.IO;

​

namespace Rextester

{

    public class Program

    {

        public static void Main(string[] args)

        {

            byte[] data = Convert.FromBase64String("e6nP7hkzPE8Dl7SqZ0GanuBb9C5QWapeqSKH6OcUcIwuVoC+3xytm7bM9anZdeYw6y877Kncr6lKKfwkokcXnpEyxOjTSkr++gpJaHMse/Pgrp32GEHpj3GiR/kdgoZlHRE9gJ0e0m2V4J5AnkS25akZ1kMbkMJXSusfHCklfqVVk6wWRYIEj83vTL3OBagjw698bOnU1oDRelxL6ki98QvCOtMdhW83vrJ1lXy+DBJfJmq9QhytZUCER4nuJRj2vz4oc85fvoOgE7wdeArtZB4+7gc1QbWia3ltFS0Fn0sEglY7t7V5JsLuBoguHyBn38MTtPLpQXlnq+hBGS182C1gRGqA+v1LdXMs6lRx/VcFbXhvIo555dr1n4+vCQqRhQdjnNoegbbQGFvL0wQQLukHtaqsLAJFIGIALDIcD+y/ojtbi3l57yFmw9Xg/oXlTZyO4zSxsHvox5GtWLhAvQ==");

            byte[] iv = new byte[16];

            Buffer.BlockCopy(data,0,iv,0,16);

            byte[] key = StringToByteArray("8ead6a94d9916a646371fa6db82fab3d9945bcec43a132de50e0a9bb2f60b236");

            string decrypted = Unpad(Decrypt(key, iv, data));

            Console.WriteLine(decrypted);

            string test = "authtoken=2GEsAf8a9JoFnaRchLTaf&email=remybdr@orange.fr&microconnect=300590&os_type=android&os_version=22&app_version=4.4.6&device_id=4870020582858325&device_model=LGLG-M700N&token_id=APA91bE_cIN7SEi1tGmU8ZU_L4mzwSxiQqdUPOsWVmrKvjiFiuqq5Wte9kHe81891X4t-DYXTpw87KDYEJZhrA8WMlIjVK1a207yPHQ3oZOCWO_AoCWp0Iiy61b-IDeKiqT-ni5WCSIi";

            string encrypt = Encrypt(key, test);

            Console.WriteLine("zz");

            Console.WriteLine(encrypt);

            Console.WriteLine("rr");

            byte[] encryptedBytes = Convert.FromBase64String(encrypt);

            Buffer.BlockCopy(encryptedBytes,0,iv,0,16);

            decrypted = Unpad(Decrypt(key, iv, encryptedBytes));

            Console.WriteLine(decrypted);

        }

        public static byte[] StringToByteArray(string hex) {

    return Enumerable.Range(0, hex.Length)

                     .Where(x => x % 2 == 0)

                     .Select(x => Convert.ToByte(hex.Substring(x, 2), 16))

                     .ToArray();

}

        public static byte[] Decrypt(byte[] key, byte[] iv, byte[] data)

        {

         // Declare the string used to hold

            // the decrypted text.

            byte[] decrypted = null;

​

            // Create an AesCryptoServiceProvider object

            // with the specified key and IV.

            using (AesCryptoServiceProvider aesAlg = new AesCryptoServiceProvider())

            {

                aesAlg.Mode = CipherMode.CBC;

                aesAlg.Key = key;

                aesAlg.IV = iv;

                // Create a decrytor to perform the stream transform.

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

​

                // Create the streams used for decryption.

                using (MemoryStream msDecrypt = new MemoryStream(data))

                {

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

                    {

                            decrypted = new byte[1024*1024];

                            int read = csDecrypt.Read(decrypted, 0, decrypted.Length);

                        Array.Resize(ref decrypted, read);

                    }

                }

​

            }

​

            return decrypted;   

        }

        public static string Unpad(byte[] text)

        {

            int trim = 0;

            for(int i = text.Length -1; i >= 0; i--)

            {

                    if (text[i] == 0)

                    {

                     trim++;   

                    }

            }

            byte[] newArray =new byte[text.Length - trim];

            Buffer.BlockCopy(text, 0, newArray, 0, text.Length - trim);

            return Encoding.UTF8.GetString(newArray);

        }

        public static string Encrypt(byte[] key, string text)

        {

            Random random = new Random();

            byte[] iv = new byte[16];

            random.NextBytes(iv);

            byte[] data = Encoding.UTF8.GetBytes(Pad(text));

            byte[] encrypted = null;

            using (AesCryptoServiceProvider aesAlg = new AesCryptoServiceProvider())

            {

                aesAlg.Mode = CipherMode.CBC;

                aesAlg.Key = key;

                aesAlg.IV = iv;

                // Create a decrytor to perform the stream transform.

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

​

                // Create the streams used for decryption.

                using (MemoryStream msEncrypt = new MemoryStream(data))

                {

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

                    {

                            encrypted = new byte[1024*1024];

                            int read = csEncrypt.Read(encrypted, 0, encrypted.Length);

                        Array.Resize(ref encrypted, read);

                    }

                }

​

            }

            byte[] final = new byte[iv.Length + encrypted.Length];

            Buffer.BlockCopy(iv, 0, final, 0, iv.Length);

            Buffer.BlockCopy(encrypted, 0, final, iv.Length, encrypted.Length);

            return Convert.ToBase64String(final);

        }

        public static string Pad(string source)

        {

         int padLength = 16 - (source.Length % 16);

        for (int i = 0; i < padLength; i++) {

            source = source + '\u0000';

        }

           return source;

        }

    }

}