SslProtocolVersion Enum

public enum SslProtocolVersion

Specifies the SSL/TLS protocol versions that can be used by the SslStream class.

Members

Remarks

The SslProtocolVersion enumeration is used to configure the specific SSL or TLS protocol version that an SslStream instance will use for communication. When creating an SslStream, you can specify the desired protocol version to ensure compatibility or enforce security standards.

For enhanced security, it is strongly recommended to use Tls12 or Tls13. Older protocols like SSL 2.0, SSL 3.0, TLS 1.0, and TLS 1.1 have known vulnerabilities and should be avoided whenever possible.

Example

The following example demonstrates how to create an SslStream and explicitly set the protocol version to TLS 1.2.

using System;
using System.Net.Security;
using System.Net.Sockets;
using System.Security.Cryptography.X509Certificates;

public class Example
{
    public static void Main(string[] args)
    {
        try
        {
            // Assuming you have a TcpClient connected and authenticated
            TcpClient client = new TcpClient("example.com", 443);
            SslStream sslStream = new SslStream(
                client.GetStream(),
                false,
                new RemoteCertificateValidationCallback(ValidateServerCertificate),
                null);

            // Authenticate the client using the specified protocol version
            sslStream.AuthenticateAsClient("example.com", null, SslProtocolVersion.Tls12, false);

            Console.WriteLine("Authentication successful using TLS 1.2.");

            // You can now use sslStream for secure communication
            // ...

            sslStream.Close();
            client.Close();
        }
        catch (Exception ex)
        {
            Console.WriteLine($"An error occurred: {ex.Message}");
        }
    }

    public static bool ValidateServerCertificate(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors)
    {
        // In a real application, you would implement robust certificate validation logic.
        // For this example, we'll accept any valid certificate.
        if (sslPolicyErrors == SslPolicyErrors.None)
            return true;

        Console.WriteLine($"Certificate error: {sslPolicyErrors}");

        // Do not return true for invalid certificates in production environments.
        return false;
    }
}

Requirements

See Also

• SslStream Class
• System.Net.Security Namespace