using System.Security.Cryptography;

using System;

using System.Text;

using System.Linq;

​

public class Decryption

    {

        public static void Main()

        {

            string finalOutput = DecryptAES();

            Console.WriteLine(finalOutput);

        }

        public static string DecryptAES()

        {

            string passphrase = "this-is-a-test-passphrase";

            string inputData = "94b681ef29d9a6d7-e6fa36c4c00977de1745fc63-a1ad0481bdbeeaa02c013a2dce82520ddd762355e18f1e2f20c0ea9d001ece24e9b8216ed4b9c6a06e1ef34c953f80";

​

            string[] arr = inputData.Split('-');

            byte[] salt = Convert.FromHexString(arr[0]);

            byte[] iv = Convert.FromHexString(arr[1]);

            byte[] data = Convert.FromHexString(arr[2]);

            byte[] key = GetPbkdf2Bytes(passphrase, salt, 1000, 32);

​

            return AESDecryption(data, key, iv);

        }

​

        public static string AESDecryption(byte[] data, byte[] key, byte[] iv)

        {

            AesCryptoServiceProvider AEScryptoProvider = new AesCryptoServiceProvider();

            AEScryptoProvider.BlockSize = 128;

            AEScryptoProvider.KeySize = 256;

            AEScryptoProvider.Key = key;

            AEScryptoProvider.IV = iv;

            AEScryptoProvider.Mode = CipherMode.CBC;

            AEScryptoProvider.Padding = PaddingMode.PKCS7;

​

            byte[] txtByteData = data;

            ICryptoTransform trnsfrm = AEScryptoProvider.CreateDecryptor();

​

            byte[] result = trnsfrm.TransformFinalBlock(txtByteData, 0, txtByteData.Length);

            return ASCIIEncoding.ASCII.GetString(result);

        }

​

        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();

        }

​

        private static byte[] GetPbkdf2Bytes(string password, byte[] salt, int iterations, int outputBytes)

        {

            var pbkdf2 = new Rfc2898DeriveBytes(password, salt);

            pbkdf2.IterationCount = iterations;

            return pbkdf2.GetBytes(outputBytes);

        }

    }