using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Security.Cryptography;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WindowsFormsApp8
{
    public partial class Form1 : Form
    {

        public Form1()
        {
            InitializeComponent();
        }
        ConversionHandler c = new ConversionHandler();
        class ConversionHandler
        {

            public byte[] StringToByteArray(string s)
            {
                return CharArrayToByteArray(s.ToCharArray());
            }

            public byte[] CharArrayToByteArray(char[] array)
            {
                return Encoding.ASCII.GetBytes(array, 0, array.Length);
            }

            public string ByteArrayToString(byte[] array)
            {
                return Encoding.ASCII.GetString(array);
            }

            public string ByteArrayToHexString(byte[] array)
            {
                string s = ""; int i; for (i = 0; i < array.Length; i++)
                {
                    s = s + NibbleToHexString((byte)((array[i] >> 4) & 0x0F)) + NibbleToHexString((byte)(array[i] & 0x0F));
                }
                return s;
            }

            public byte[] HexStringToByteArray(string s)
            {
                byte[] array = new byte[s.Length / 2];
                char[] chararray = s.ToCharArray(); int i;
                for (i = 0; i < s.Length / 2; i++)
                {
                    array[i] = (byte)(((HexCharToNibble(chararray[2 * i]) << 4) & 0xF0) | ((HexCharToNibble(chararray[2 * i + 1]) & 0x0F)));
                }
                return array;
            }

            public string NibbleToHexString(byte nib)
            {
                string s; if (nib < 10)
                {
                    s = nib.ToString();
                }
                else
                {
                    char c = (char)(nib + 55);
                    s = c.ToString();
                }
                return s;
            }

            public byte HexCharToNibble(char c)
            {
                byte value = (byte)c; if (value < 65)
                {
                    value = (byte)(value - 48);
                }
                else { value = (byte)(value - 55);
                }
                return value;
            }
        }
        /* MD5CryptoServiceProvider myMD5 = new MD5CryptoServiceProvider();
         RandomNumberGenerator rnd = RandomNumberGenerator.Create();
         byte[] input = new byte[20];
         byte[] hashValue;
         //generates some random input
         rnd.GetBytes(input);
         //computes the hash
         hashValue = myMD5.ComputeHash(input);
         */

            public bool CheckAutenticity(byte[] mes, byte[] mac, byte[] key)
            {
                myMAC.Key = key;
                if (CompareByteArrays(myMAC.ComputeHash(mes), mac, myMAC.HashSize / 8) == true)
                {
                    return true;
                }
                else
                {
                    return false;
                }
            }


            public int MACByteLength()
            {
                return myMAC.HashSize / 8;
            }

            private bool CompareByteArrays(byte[] a, byte[] b, int len)
            {
                for (int i = 0; i < len; i++)
                    if (a[i] != b[i])
                        return false;
                return true;
            }


        RandomNumberGenerator rnd = RandomNumberGenerator.Create();
        byte[] key = new byte[16];





        private void label7_Click(object sender, EventArgs e)
        {

        }

        private void label2_Click(object sender, EventArgs e)
        {

        }

        private void label4_Click(object sender, EventArgs e)
        {

        }
        private HMAC myMAC;
        public void MACHandler()
        {


                myMAC = new System.Security.Cryptography.HMACMD5();


        }
        public byte[] ComputeMAC(byte[] mes, byte[] key)
        {
            myMAC.Key = key;
            return myMAC.ComputeHash(mes);

        }
        private void button2_Click(object sender, EventArgs e)
        {
            MACHandler();
            byte[] a=ComputeMAC(c.StringToByteArray(textBox4.Text),c.StringToByteArray(textBox1.Text));
            textBox3.Text = c.ByteArrayToString(a);
        }

        private void Form1_Load(object sender, EventArgs e)
        {

        }

        private void button1_Click(object sender, EventArgs e)
        {
            MD5CryptoServiceProvider myMD5 = new MD5CryptoServiceProvider();
            RandomNumberGenerator rnd = RandomNumberGenerator.Create();
            byte[] input = c.StringToByteArray(textBox1.Text);
            byte[] hashValue;

            hashValue = myMD5.ComputeHash(input);
            textBox2.Text = c.ByteArrayToString(hashValue);
        }
    }
}