How to accept a self-signed SSL certificate in a WCF client?

Question

This may be a stupid question but I just can't find the answer.

What I would like to do: I have a WCF service hosted by IIS. It is working perfectly, I can access the wsdl, I have a self-signed certificate for the server etc. I would like to call this service from a WPF client.

The problem is, since I have a self-signed certificate, I get the following exception when calling the service: Could not establish trust relationship for the SSL/TLS secure channel with authority 'localhost'.

If I access the site (or the service) from a browser, it is no problem, because the browser warns me about the certificate, and gives me the choice of viewing the page anyway. But the WPF client just throws an exception.

I don't want to completely turn off the authentication process, I simply would like to give the users the option of ignoring this warning (as browsers do).

Can anyone provide some code for this? If you ran into a good, detailed tutorial about this, it would be awesome too. (See, my problem with the tutorials I've found is the lack of details)

Answer 1

Here's the minimum amount of code you need to make WCF client accept an arbitrary certificate. This is not secure. Use for testing only. Don't blame me if this code goes berserk and eats your little kitten.

ServicePointManager.ServerCertificateValidationCallback +=
            new System.Net.Security.RemoteCertificateValidationCallback(EasyCertCheck);

The call back:

bool EasyCertCheck(object sender, X509Certificate cert,
        X509Chain chain, System.Net.Security.SslPolicyErrors error)
{
    return true;
}

Code shamelessly lifted from the least helpful answer to Is it possible to force the WCF test client to accept a self-signed certificate?

Answer 2

You can register the certificate yourself. If load the certificate in the client as well, and then register the it as trusted you shouldn't get that warning.

You need to find a X509CertificateCollection and add the certificate to that collection. I had this kind of problem with a SmtpClient running over Ssl.

By hooking the System.Net.ServicePointManager.ServerCertificateValidationCallback or implementing System.Net.ICertificatePolicy and identify my own installed certificate as valid/trusted (attached to the System.Net.ServicePointManager.CertificatePolicy).

This is not WCF stuff per se, but from what I could tell, this should translate to WCF as well. It all depends what WCF is uses under the hood.