using System;

using System.IO;

using System.Security.Cryptography;

using System.Text;

namespace Common.Utils

{

    public class Program

    {

        public static void Main()

        {

            string textToEncrypt = "text to encrypt";

            string keyToEncrypt = "Aesdns06";

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

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

            Console.WriteLine("Input     : '{0}'", getString(data));

            Console.WriteLine("Key       : '{0}'", getString(key));

            Console.WriteLine("Key bytes : [{0}]", String.Join(", ", key));

            Console.WriteLine("KeySize   : {0}", 256);

            var encryptedKeyObj = Encrypt(getString(data), getString(key));

            Console.WriteLine("Encrypted : {0}", encryptedKeyObj);

            // comment the line that not used

            string encryptedKey = encryptedKeyObj.iv + '.' + encryptedKeyObj.encrypted;

            //string encryptedKey = "hPH9TUHAOXbdoCa0WbL94A==.9FQ476CKAfBuyif8czmFyQ==";

            //string encryptedKey = "qO3LRz5kJqC7P0rsCrqwWQ==.f0OE99hgHOrM3Y11ZemQ5A==";

            string[] encryptedParts = encryptedKey.Split('.');

            Console.WriteLine("Decrypt from Base64 with IV : '{0}'", Program.Decrypt(encryptedParts[1], keyToEncrypt, encryptedParts[0]));

        }

​

        private static string getString(byte[] b)

        {

            return Encoding.UTF8.GetString(b);

        }

​

        public static Aes GetAES(string secretKey)

        {

            int keysize = 256;

            var keyBytes = new byte[keysize / 8];

            var secretKeyBytes = Encoding.UTF8.GetBytes(secretKey);

            Array.Copy(secretKeyBytes, keyBytes, Math.Min(keyBytes.Length, secretKeyBytes.Length));

            var aes = Aes.Create();

            aes.Mode = CipherMode.CBC;

            aes.Padding = PaddingMode.PKCS7;

            aes.KeySize = keysize;

            aes.BlockSize = 128;//AES es siempre 128 el blocksize

            aes.Key = keyBytes;

            aes.GenerateIV();

            return aes;

        }

        private static byte[] Encrypt(byte[] plainBytes, Aes aes)

        {

            byte[] result;

            using (var encryptor = aes.CreateEncryptor())

            using (var resultStream = new MemoryStream())

            {

                using (var aesStream = new CryptoStream(resultStream, encryptor, CryptoStreamMode.Write))

                using (var plainStream = new MemoryStream(plainBytes))

                {

                    plainStream.CopyTo(aesStream);

                }

                return result = resultStream.ToArray();

            }

        }

        private static byte[] Decrypt(byte[] encryptedData, Aes aes)

        {

            return aes.CreateDecryptor()

                .TransformFinalBlock(encryptedData, 0, encryptedData.Length);

        }

        // Encrypts plaintext using AES 128bit key and a Chain Block Cipher and returns a base64 encoded string

        public static dynamic Encrypt(string plainText, string key)

        {

            var aes = GetAES(key);

            var plainBytes = Encoding.UTF8.GetBytes(plainText);

            var ret = new

            {

                encrypted = Convert.ToBase64String(Encrypt(plainBytes, aes)),

                iv = Convert.ToBase64String(aes.IV)

            };

            return ret;

        }

        public static string Decrypt(string encryptedText, string key, string iv)

        {

            var encryptedBytes = Convert.FromBase64String(encryptedText);

            var aes = GetAES(key);

            aes.IV = Convert.FromBase64String(iv);

            return Encoding.UTF8.GetString(Decrypt(encryptedBytes, aes));

        }

    }

}

​