Represents a channel binding that can be used to provide a secure identity for a channel. This interface is implemented by classes that provide channel binding tokens (CBTs). Channel binding tokens are cryptographic assertions about the underlying transport layer that can be used to prevent man-in-the-middle attacks.

Summary

The IChannelBinding interface is a core component in .NET's security model for establishing trust between communicating endpoints. It allows applications to verify the identity of the peer by exchanging cryptographic information related to the transport connection. This is particularly important for protocols like TLS/SSL where the server's certificate verifies its identity, but channel binding can add an extra layer of assurance by binding that identity to the specific transport session.

Members

Methods

GetChannelBinding(System.Security.Cryptography.X509Certificates.X509Certificate2, System.Byte[], System.Int32, System.Int32)

Retrieves a channel binding token for the specified certificate and data.

bool GetChannelBinding(X509Certificate2 localCertificate, byte[] data, int offset, int count)
Name Type Description
localCertificate System.Security.Cryptography.X509Certificates.X509Certificate2 The local certificate used for channel binding.
data byte[] A buffer to store the channel binding token.
offset int The zero-based position in data where the channel binding token is written.
count int The maximum number of bytes to write to data.

Return Value

bool: true if the channel binding token was successfully retrieved; otherwise, false.

GetChannelBinding(System.Byte[], System.Int32, System.Int32)

Retrieves a channel binding token for the current connection.

bool GetChannelBinding(byte[] data, int offset, int count)
Name Type Description
data byte[] A buffer to store the channel binding token.
offset int The zero-based position in data where the channel binding token is written.
count int The maximum number of bytes to write to data.

Return Value

bool: true if the channel binding token was successfully retrieved; otherwise, false.

Properties

ChannelBindingKind

Gets the kind of channel binding token being used.

System.Security.Cryptography.X509Certificates.X509CertificateClaimSet ChannelBindingKind { get; }

Return Value

System.Security.Cryptography.X509Certificates.X509CertificateClaimSet: The kind of channel binding token.

Usage

The IChannelBinding interface is typically implemented by network classes that establish secure communication channels, such as System.Net.Security.SslStream. Developers can use this interface to access channel binding information, which can be used for advanced security scenarios, such as mutual authentication or enhancing the integrity of communication sessions. 


// Example: Obtaining channel binding information (conceptual)
using System.Net.Security;
using System.Security.Cryptography.X509Certificates;
using System.IO;

// Assume 'sslStream' is an established SslStream instance
IChannelBinding channelBinding = sslStream as IChannelBinding;

if (channelBinding != null)
{
    // Example: Get channel binding for a specific certificate
    X509Certificate2 clientCertificate = GetClientCertificate(); // Your method to get certificate
    byte[] bindingData = new byte[1024];
    int bytesWritten = 0;

    if (channelBinding.GetChannelBinding(clientCertificate, bindingData, 0, bindingData.Length))
    {
        Console.WriteLine($"Channel binding retrieved: {bytesWritten} bytes");
        // Process bindingData for verification
    }
    else
    {
        Console.WriteLine("Failed to retrieve channel binding.");
    }

    // Example: Get channel binding for the current connection
    byte[] currentBindingData = new byte[1024];
    if (channelBinding.GetChannelBinding(currentBindingData, 0, currentBindingData.Length))
    {
        Console.WriteLine($"Current connection channel binding retrieved.");
        // Process currentBindingData
    }
}

Remarks

Channel binding tokens provide a mechanism to cryptographically bind a security identity to a specific transport connection. This helps to mitigate certain man-in-the-middle attacks by ensuring that the identity of the peer is consistent throughout the communication session and is tied to the underlying transport.

Requirements

Framework Versions

Supported in .NET Framework 4.5 and later, .NET Core 2.0 and later.

Namespace

System.Net.Security

Assembly

System.Net.Primitives (for .NET Core and .NET 5+) or System.dll (for .NET Framework)