pasoib9_client

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Net;
using System.Net.Sockets;
using System.Windows.Forms;
using System.Security.Cryptography;
using System.Security.Permissions;
using System.Security.Cryptography.Pkcs;
using System.IO;
using System.Security.Cryptography.X509Certificates;


namespace PASOIB9
{
    public partial class Form1 : Form
    {
        Socket connectionSocket;
        byte[] signedMessage;
        byte[] encryptedMessage;
        int opflag = 0;

        public Form1()
        {
            InitializeComponent();
        }


        private void ConnectButton_Click(object sender, EventArgs e)
        {
            string ip = Convert.ToString(ipBox.Text);
            int port = Convert.ToInt32(portBox.Text);
            // Trying to establish a client-server connection
            try
            {
                IPEndPoint ipPoint = new IPEndPoint(IPAddress.Parse(ip), port);
                connectionSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
                connectionSocket.Connect(ipPoint);
            }
            catch (Exception exc)
            {
                Console.WriteLine(exc.Message);
            }
        }

        private void DisconnectButton_Click(object sender, EventArgs e)
        {
            // Closing connection with server and releasing socket
            byte[] stopMessage = Encoding.Unicode.GetBytes("stop");
            connectionSocket.Send(stopMessage);
            connectionSocket.Shutdown(SocketShutdown.Both);
            connectionSocket.Close();
        }

        private void SendButton_Click(object sender, EventArgs e)
        {
            string msgText = "";
            string msgCaption = "";
            if (UserMessageBox.Text.Length == 0)
            {
                msgText = "Empty message for encryption";
                msgCaption = "Encryption error";

            }
            else if (ipBox.Text.Length == 0)
            {
                msgText = "Enter connection IP";
                msgCaption = "IP error";
            }
            else if (portBox.Text.Length == 0)
            {
                msgText = "Enter connection port";
                msgCaption = "Port error";
            }
            if (msgCaption != "" && msgText != "")
                MessageBox.Show(msgText, msgCaption, MessageBoxButtons.OK);

            switch (opflag)
            {
                case 0:
                    {
                        string flagMsg = "message";
                        byte[] data = Encoding.Unicode.GetBytes(flagMsg);
                        connectionSocket.Send(data);
                        string message = Convert.ToString(UserMessageBox);
                        byte[] data2 = Encoding.Unicode.GetBytes(message);
                        break;
                    }
                case 1:
                    {
                        string flagMsg = "sign";
                        byte[] data = Encoding.Unicode.GetBytes(flagMsg);
                        connectionSocket.Send(data);
                        connectionSocket.Send(signedMessage);
                        break;
                    }
                case 2:
                    {
                        string flagMsg = "encrypt";
                        byte[] data = Encoding.Unicode.GetBytes(flagMsg);
                        connectionSocket.Send(data);
                        connectionSocket.Send(encryptedMessage);
                        break;
                    }
            }
            opflag = 0;

        }

        private void EncryptButton_Click(object sender, EventArgs e)
        {
            // Receiving certificate for encryption
            var certStore = new X509Store(StoreName.My, StoreLocation.CurrentUser);
            certStore.Open(OpenFlags.OpenExistingOnly | OpenFlags.ReadWrite);
            X509Certificate2Collection certCollection = certStore.Certificates;
            X509Certificate2Collection selectCert = X509Certificate2UI.SelectFromCollection(certCollection, "Certificate Select",
                "Select a certificate from the following list", X509SelectionFlag.SingleSelection);
            X509Certificate2 curCert = selectCert[0];
            // Get current user message
            encryptedMessage = Encoding.Unicode.GetBytes(Convert.ToString(UserMessageBox.Text));
            ContentInfo contentInfo = new ContentInfo(encryptedMessage);
            SignedCms cms = new SignedCms(contentInfo);
            CmsSigner signer = new CmsSigner(curCert);
            cms.ComputeSignature(signer, false);
            signedMessage = cms.Encode();
            var contentInfo2 = new ContentInfo(signedMessage);
            var recipients = new CmsRecipient(SubjectIdentifierType.IssuerAndSerialNumber, curCert);
            var cms2 = new EnvelopedCms(contentInfo2);
            cms2.Encrypt(recipients);
            encryptedMessage = cms2.Encode();
            StringBuilder sb = new StringBuilder();
            foreach (var b in encryptedMessage)
            {
                sb.Append(b);
            }
            File.WriteAllBytes("file.enc", encryptedMessage);
            encMesssageBox.Text = sb.ToString();

            opflag = 2;
        }

        private void SignButton_Click(object sender, EventArgs e)
        {
            // Receiving certificate for encryption
            var certStore = new X509Store(StoreName.My, StoreLocation.CurrentUser);
            certStore.Open(OpenFlags.OpenExistingOnly | OpenFlags.ReadWrite);
            X509Certificate2Collection certCollection = certStore.Certificates;
            X509Certificate2Collection selectCert = X509Certificate2UI.SelectFromCollection(certCollection, "Certificate Select",
                "Select a certificate from the following list", X509SelectionFlag.SingleSelection);
            X509Certificate2 curCert = selectCert[0];

            // Get current user message
            signedMessage = Encoding.Unicode.GetBytes(Convert.ToString(UserMessageBox.Text));
            ContentInfo contentInfo = new ContentInfo(signedMessage);
            SignedCms cms = new SignedCms(contentInfo);
            CmsSigner signer = new CmsSigner(curCert);
            cms.ComputeSignature(signer, false);
            signedMessage = cms.Encode();
            File.WriteAllBytes("file.sign", signedMessage);

            StringBuilder sb = new StringBuilder();
            foreach (var b in signedMessage)
            {
                sb.Append(b);
            }

            signMessageBox.Text = sb.ToString();
            opflag = 1;
        }

        private void HashButton_Click(object sender, EventArgs e)
        {
            HashAlgorithm hashAlg = HashAlgorithm.Create("GOST3411");
            byte[] messageHash = new UTF8Encoding().GetBytes(Convert.ToString(UserMessageBox.Text));
            var hash = hashAlg.ComputeHash(messageHash);
            StringBuilder sb = new StringBuilder();
            foreach (var b in hash)
            {
                sb.Append(b);
            }
            MessageHash.Text = sb.ToString();
        }

    }
}