ProtectionLevel Enumeration

Indicates the security services requested for an authenticated stream.

Namespace:  System.Net.Security
Assembly:  System (in System.dll)

public enum ProtectionLevel

Member nameDescription
NoneAuthentication only.
SignSign data to help ensure the integrity of transmitted data.
EncryptAndSignEncrypt and sign data to help ensure the confidentiality and integrity of transmitted data.

This enumeration is used by the NegotiateStream class.

Windows 95, Windows 98, Windows 98 Second Edition, Windows Millennium Edition Platform Note: Only None is supported.

The following code example demonstrates creating and using a client-side NegotiateStream.


using System;
using System.Net;
using System.Net.Security;
using System.Net.Sockets;
using System.Security.Principal;

namespace Examples.NegotiateStreamExample
{
    public class SynchronousAuthenticatingTcpClient 
    {
        public static void Main(String[] args)  
        {
            // Establish the remote endpoint for the socket.
            // For this example, use the local machine.
            IPHostEntry ipHostInfo = Dns.GetHostEntry(Dns.GetHostName());
            IPAddress ipAddress = ipHostInfo.AddressList[0];
            // Client and server use port 11000. 
            IPEndPoint remoteEP = new IPEndPoint(ipAddress,11000);
            // Create a TCP/IP socket.
           TcpClient client = new TcpClient();
            // Connect the socket to the remote endpoint.
            client.Connect(remoteEP);
            Console.WriteLine("Client connected to {0}.",
                remoteEP.ToString());
            // Ensure the client does not close when there is 
            // still data to be sent to the server.
            client.LingerState = (new LingerOption(true,0));
            // Request authentication.
            NetworkStream clientStream = client.GetStream();
            NegotiateStream authStream = new NegotiateStream(clientStream); 
            // Request authentication for the client only (no mutual authentication).
            // Authenicate using the client's default credetials.
            // Permit the server to impersonate the client to access resources on the server only.
            // Request that data be transmitted using encryption and data signing.
            authStream.AuthenticateAsClient(
                 (NetworkCredential) CredentialCache.DefaultCredentials, 
                 "",
                 ProtectionLevel.EncryptAndSign,
                 TokenImpersonationLevel.Impersonation);
            DisplayAuthenticationProperties(authStream);
            DisplayStreamProperties(authStream);
            if (authStream.CanWrite)
            {
                 // Encode the test data into a byte array.
                byte[] message = System.Text.Encoding.UTF8.GetBytes("Hello from the client.");
                authStream.Write(message, 0, message.Length);
          authStream.Flush();
                Console.WriteLine("Sent {0} bytes.", message.Length);
         }
         // Close the client connection.
            authStream.Close();
            Console.WriteLine("Client closed.");

    }
         static void DisplayStreamProperties(NegotiateStream stream)
        {
             Console.WriteLine("Can read: {0}", stream.CanRead);
             Console.WriteLine("Can write: {0}", stream.CanWrite);
             Console.WriteLine("Can seek: {0}", stream.CanSeek);
             try 
             {
                 // If the underlying stream supports it, display the length.
                 Console.WriteLine("Length: {0}", stream.Length);
             } catch (NotSupportedException)
             {
                     Console.WriteLine("Cannot get the length of the underlying stream.");
             }

             if (stream.CanTimeout)
             {
                 Console.WriteLine("Read time-out: {0}", stream.ReadTimeout);
                 Console.WriteLine("Write time-out: {0}", stream.WriteTimeout);
             }
        }
         static void DisplayAuthenticationProperties(NegotiateStream stream)
        {
             Console.WriteLine("IsAuthenticated: {0}", stream.IsAuthenticated);
            Console.WriteLine("IsMutuallyAuthenticated: {0}", stream.IsMutuallyAuthenticated);
            Console.WriteLine("IsEncrypted: {0}", stream.IsEncrypted);
            Console.WriteLine("IsSigned: {0}", stream.IsSigned);
            Console.WriteLine("ImpersonationLevel: {0}", stream.ImpersonationLevel);
            Console.WriteLine("IsServer: {0}", stream.IsServer);
        }
    }
}


.NET Framework

Supported in: 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
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