using System;

using System.IO;

using System.Linq;

using System.Security.Cryptography;

using System.Text;

public class Program

{

        //NO SE VAN A UTILIZAR LOS METODOS DE GENERACION DE LLAVES

​

        //private static readonly byte[] Salt = new byte[] { 13, 90, 30, 56, 50, 60, 76, 80 };

​

        //public static byte[] CreateKey(string password)

        //{

        //    return CreateKey(password, 32);

        //}

​

        //public static byte[] CreateKey(string password, int keyBytes)

        //{

        //    const int Iterations = 300;

        //    var keyGenerator = new Rfc2898DeriveBytes(password, Salt, Iterations);

​

        //    return keyGenerator.GetBytes(keyBytes);

        //}

​

​

        // SE CAMBIA EL MODO DE RETORNO A STRING YA QUE DEVUELVE UN BASE64

        public static string EncryptStringToBytes_Aes(string password, byte[] Key, byte[] IV)

        {

            // Check arguments.

            if (password == null || password.Length <= 0)

            {

                throw new ArgumentNullException("password");

            }

​

            if (Key == null || Key.Length <= 0)

            {

                throw new ArgumentNullException("Key");

            }

            if (IV == null || IV.Length <= 0)

            {

                throw new ArgumentNullException("IV");

            }

​

            string encrypted;

​

            // Create an AesCryptoServiceProvider object

            // with the specified key and IV.

            using (AesCryptoServiceProvider aesAlg = new AesCryptoServiceProvider())

            {

                aesAlg.Key = Key;

                aesAlg.IV = IV;

                aesAlg.Mode = CipherMode.CBC;        // SE ESPECIFICA EL MODO Y PADDING DE ENCRYPTAMIENTO

                aesAlg.Padding = PaddingMode.PKCS7;

​

                // Create a decrytor to perform the stream transform.

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

​

                // Create the streams used for encryption.

                using (MemoryStream msEncrypt = new MemoryStream())

                {

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

                    {

                        using (StreamWriter swEncrypt = new StreamWriter(csEncrypt))

                        {

                            //Write all data to the stream.

                            swEncrypt.Write(password);

                        }

                        encrypted = Convert.ToBase64String(msEncrypt.ToArray()); //SE ADICIONA LA CONVERSIÓN A BASE64

                    }

                }

            }

            // Return the encrypted bytes from the memory stream.

            return encrypted;

        }

​

        // SE CAMBIA EL TIPO DEL PARAMETRO cipherText PARA QUE RECIBA UN STRING Y NO UN ARRAY DE BYTES

        public static string DecryptStringFromBytes_Aes(string cipherText, byte[] Key, byte[] IV)

        {

            // Check arguments.

            if (cipherText == null || cipherText.Length <= 0)

            {

                throw new ArgumentNullException("cipherText");

            }

            if (Key == null || Key.Length <= 0)

            {

                throw new ArgumentNullException("Key");

            }

            if (IV == null || IV.Length <= 0)

            {

                throw new ArgumentNullException("IV");

            }

​

            // Declare the string used to hold

            // the decrypted text.

            string plaintext = null;

​

            // Create an AesCryptoServiceProvider object

            // with the specified key and IV.

            using (AesCryptoServiceProvider aesAlg = new AesCryptoServiceProvider())

            {

                aesAlg.Key = Key;

                aesAlg.IV = IV;

                aesAlg.Mode = CipherMode.CBC;        // SE ESPECIFICA EL MODO Y PADDING DE ENCRYPTAMIENTO

                aesAlg.Padding = PaddingMode.PKCS7;

​

                // 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(Convert.FromBase64String(cipherText)))

                {

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

                    {

                        using (StreamReader srDecrypt = new StreamReader(csDecrypt))

                        {

                            // Read the decrypted bytes from the decrypting stream

                            // and place them in a string.

                            plaintext = srDecrypt.ReadToEnd();

                        }

                    }

                }

            }

            return plaintext;

        }

​

        public static void Main()

        {

            //SE OBTIENE UN ARRAY DE 32 BYTES QUE ES EL MAXIMO QUE PERMITE LA LLAVE

            var key = Encoding.UTF8.GetBytes("2D51C61B629D914D9C6AB38E8C9863118664A3DD52D6FC81E57841A33080671F").Take(32).ToArray();

            var IV = Encoding.UTF8.GetBytes("!QAZ2WYX#EDC4RFV").Take(16).ToArray();

            string plaintext = "Test PS";

​

            //SE ENVIA LA LLAVE RECORTADA DESPUES DE OBTENER LOS BYTES

            var ciphertext = EncryptStringToBytes_Aes(plaintext, key, IV);

            Console.WriteLine(ciphertext);

            var de = DecryptStringFromBytes_Aes(ciphertext, key, IV);

            Console.WriteLine(de);

​

​

            //NO SE VA A UTILIZAR 

            //var iv = CreateKey("!QAZ2WYX#EDC4RFV", 16);

            //var key = CreateKey("2D51C61B629D914D9C6AB38E8C9863118664A3DD52D6FC81E57841A33080671F");

        }

}