Comparing X509Certificate Subject with User Input

Recently I encountered an issue where I was comparing the certificate name of an X509Certificate with a user input.

The issue was that the subject a user would see on the certificate property has spaces in it

E.g. CN = xxx

However, when querying the subject of an X509Certificate2 object, it won’t have any spaces in it

E.g. CN=xxx

This would make the subject comparison fail

The fix was to use X500DistinguishedName for comparison of subject. Below is a snippet    

X509Certificate2 certificate = new X509Certificate2(@"xxx.cer");

// certificate.Subject results in CN=xxx

            X500DistinguishedName certificateSubjectname = new X500DistinguishedName(certificate.Subject);

            X500DistinguishedName configuredSubjectname = new X500DistinguishedName("CN = xxx");

            bool result = string.Equals(certificateSubjectname.Decode(X500DistinguishedNameFlags.None), configuredSubjectname.Decode(X500DistinguishedNameFlags.None), StringComparison.CurrentCulture);