AES256 for strings (English explanations)

using System;
using System.IO;
using System.Security.Cryptography;     //To use the cryptography functions
using System.Text;

namespace AES256
{
    class Program
    {
        /*      This is an implementation of the encryption algorithm AES256
         *          for strings, very usefull to encrypt messages you don't
         *          want an unauthorized person to have access.
         *
         *      Created by: Andrew Vargas
         *      Facebook: https://www.facebook.com/andrewvargas1991
         */

        static void Main(string[] args)
        {
            Console.Write("Digite alguma coisa: ");
            String originalString = Console.ReadLine();  //Read the string to be encrypted

            String encryptedString = Criptografia.Encrypt(originalString);    //Call the encryption method
            String decryptedString = Criptografia.Decrypt(encryptedString);    //Call the decryption method

            //Print the original string, the encrypted and the decrypted
            Console.WriteLine("\n\nOriginal: " + originalString);
            Console.WriteLine("Encrypted: " + encryptedString);
            Console.WriteLine("Decrypted: " + decryptedString);

            Console.WriteLine("\nPress any key to leave...");
            Console.ReadKey();
        }

        public class Criptografia   //Class that contains the necessary variables and functions
        {
            /// Array of bytes utilized by the cryptography (External Key)
            private static byte[] bIV =
                { 0x50, 0x08, 0xF1, 0xDD, 0xDE, 0x3C, 0xF2, 0x18,
                    0x44, 0x74, 0x19, 0x2C, 0x53, 0x49, 0xAB, 0xBC };

            /*      Important: Case you want to get the key (password) from the keyboard,
                        you have to convert the string to base 64
            */
            private const string cryptoKey = "Q3JpcHRvZ3JhZmlhcyBjb20gUmluamRhZWwgLyBBRVM=";

            //Method to encrypt the string
            public static string Encrypt(string text)
            {
                try
                {
                    // If the string is not void (empty), execute the encryption
                    if (!string.IsNullOrEmpty(text))
                    {
                        // Instance the array of bytes with the keys
                        byte[] bKey = Convert.FromBase64String(cryptoKey);  //Return the cryptoKey

                        //Print the value of cryptoKey char by char
                        for (int i = 0; i < bKey.Length; i++)
                            Console.Write((char)bKey[i]);

                        byte[] bText = new UTF8Encoding().GetBytes(text);

                        // Instance the class Rijndael (Rihndael = AES)
                        Rijndael rijndael = new RijndaelManaged();

                        // Defines the keysize "256 = 8 * 32"
                        // There are other possibilities
                        // 128 (16 characters), 192 (24 characters) e 256 (32 characters)
                        rijndael.KeySize = 256;

                        // Separate space in the memory to encrypt the string
                        MemoryStream mStream = new MemoryStream();
                        // Instance the encryptor
                        CryptoStream encryptor = new CryptoStream(
                            mStream, rijndael.CreateEncryptor(bKey, bIV), CryptoStreamMode.Write);

                        // Write the encrypted data in the memory
                        encryptor.Write(bText, 0, bText.Length);
                        // Clean the encryptor
                        encryptor.FlushFinalBlock();
                        // Return the array of bytes (encrypted string)
                        return Convert.ToBase64String(mStream.ToArray());
                    }
                    else
                    {
                        // If the string is null
                        return null;
                    }
                }
                catch (Exception ex)
                {
                    // If an error occurs
                    throw new ApplicationException("Erro ao criptografar", ex);
                }
            }

            //Method to decrypt the string
            public static string Decrypt(string text)
            {
                /*      Basically it has similar implementations to the Encrypt,
                 *          with few changes, therefore I will not comment
                 */

                try
                {
                    if (!string.IsNullOrEmpty(text))
                    {
                        byte[] bKey = Convert.FromBase64String(cryptoKey);
                        byte[] bText = Convert.FromBase64String(text);

                        Rijndael rijndael = new RijndaelManaged();

                        rijndael.KeySize = 256;

                        MemoryStream mStream = new MemoryStream();
                        CryptoStream decryptor = new CryptoStream(mStream,
                            rijndael.CreateDecryptor(bKey, bIV), CryptoStreamMode.Write);

                        decryptor.Write(bText, 0, bText.Length);
                        decryptor.FlushFinalBlock();
                        UTF8Encoding utf8 = new UTF8Encoding();
                        return utf8.GetString(mStream.ToArray());
                    }
                    else
                    {
                        return null;
                    }
                }
                catch (Exception ex)
                {
                    throw new ApplicationException("Erro ao descriptografar", ex);
                }
            }
        }
    }
}