using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Security.Cryptography;
using System.Text;
using System.Threading.Tasks;

namespace BSK04042019
{
    class Program
    {
        static void Main(string[] args)
        {
            string original = "";
            int caseSwitch = 0;
            int a = 9;
            do
            {
                Console.WriteLine("Szyfrowanie z pliku wybierz 1\nSzyfrowanie wpisanego tekstu wybierz 2\n");
                int.TryParse(Console.ReadLine(), out caseSwitch);
                switch (caseSwitch)
                {
                    case 1:
                        {
                            original = File.ReadAllText(@"E:\Fabian\Test.txt");
                            Console.WriteLine("Contents of Test.txt = {0}", original);

                            // Create a new instance of the Aes
                            // class.  This generates a new key and initialization 
                            // vector (IV).
                            using (Aes myAes = Aes.Create())
                            {

                                // Encrypt the string to an array of bytes.
                                byte[] encrypted = EncryptStringToBytes_Aes(original, myAes.Key, myAes.IV);

                                // Decrypt the bytes to a string.
                                string roundtrip = DecryptStringFromBytes_Aes(encrypted, myAes.Key, myAes.IV);
                                var str = Encoding.Default.GetString(encrypted);
                                //Display the original data and the decrypted data.
                                Console.WriteLine("Original:   {0}", original);
                                Console.WriteLine("Encrypted:   {0}", str);
                                Console.WriteLine("Round Trip: {0}", roundtrip);
                            }
                            break;
                        }
                    case 2:
                        {
                            Console.WriteLine("Podaj text do zaszyfrowania: ");
                            original = Console.ReadLine();
                            using (Aes myAes = Aes.Create())
                            {

                                byte[] encrypted = EncryptStringToBytes_Aes(original, myAes.Key, myAes.IV);
                                string roundtrip = DecryptStringFromBytes_Aes(encrypted, myAes.Key, myAes.IV);

                                var str = Encoding.Default.GetString(encrypted);
                                Console.WriteLine("Original:   {0}", original);
                                Console.WriteLine("Encrypted:   {0}", str);
                                Console.WriteLine("Round Trip: {0}", roundtrip);
                            }
                            break;
                        }
                    default:
                        {
                            break;
                        }

                }

                Console.WriteLine("Aby kontynuować wybierz '9'");
                a = Convert.ToInt32(Console.ReadLine());
            } while (a == 9);

            Console.ReadKey();
        }
        static byte[] EncryptStringToBytes_Aes(string plainText, byte[] Key, byte[] IV)
        {
            // Check arguments.
            if (plainText == null || plainText.Length <= 0)
                throw new ArgumentNullException("plainText");
            if (Key == null || Key.Length <= 0)
                throw new ArgumentNullException("Key");
            if (IV == null || IV.Length <= 0)
                throw new ArgumentNullException("IV");
            byte[] encrypted;

            // Create an Aes object
            // with the specified key and IV.
            using (Aes aesAlg = Aes.Create())
            {
                aesAlg.Key = Key;
                aesAlg.IV = IV;

                // Create an encryptor 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(plainText);
                        }
                        encrypted = msEncrypt.ToArray();
                    }
                }
            }

            // Return the encrypted bytes from the memory stream.
            return encrypted;
        }

        static string DecryptStringFromBytes_Aes(byte[] 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 Aes object
            // with the specified key and IV.
            using (Aes aesAlg = Aes.Create())
            {
                aesAlg.Key = Key;
                aesAlg.IV = IV;

                // Create a decryptor to perform the stream transform.
                ICryptoTransform decryptor = aesAlg.CreateDecryptor(aesAlg.Key, aesAlg.IV);

                // Create the streams used for decryption.
                using (MemoryStream msDecrypt = new MemoryStream(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;

        }

    }
}