muhaisen

using Newtonsoft.Json;
using System;
using System.IO;
using System.IO.Compression;
using System.Security.Cryptography;
using System.Text;

namespace ManagedAES
{
    /// <summary>

muhaisen

        public static void Decrypt()
        {
            using (AesManaged myAes = new AesManaged())
            {
                var protected_string = "W+YnphJ2T8pH4X+FNTwZvFPab+R4wRbZg/6HuyZ8Ese15LYp1UJLs7HvmIco4w6A";
                byte[] protected_bytes = RetrieveCipher(protected_string);
                // Encryption key
                var encrption_key = Convert.FromBase64String(Constants.s_encrption_key);
                // IV
                var byte_IV = RetrieveIv(protected_string);

muhaisen

        /// <summary>
        /// Decrypts the cipher text.
        /// </summary>
        /// <param name="cipherText"></param>
        /// <param name="Key"></param>
        /// <param name="IV"></param>
        /// <returns></returns>
        static string DecryptStringFromBytes_Aes(byte[] cipherText, byte[] Key, byte[] IV)
        {
            // Check arguments.

muhaisen

        /// <summary>
        /// Retivers the cipher text without the IV
        /// </summary>
        /// <param name="base64_cipher_text"></param>
        /// <returns></returns>
        public static byte[] RetrieveCipher(string base64_cipher_text)
        {

            byte[] cipher_binary = Convert.FromBase64String(base64_cipher_text);
            var length = cipher_binary.Length - 16;

muhaisen

        /// <summary>
        /// Returns the IV needed for decryption. 16 Bytes
        /// </summary>
        /// <param name="base64_cipher_text"></param>
        /// <returns></returns>
        public static byte[] RetrieveIv(string base64_cipher_text)
        {
            // Just 16 the first bytes
            // 16 not divisable by 3 (4 characters per 3 bytes)
            // 4 -> 3