Search code examples
c#x509certificatex509certificate2

Given two X509Certificate how to tell if one is signed by the other

I have two serialized certificates in the DB from which I can construct the X509Certificate. How to tell if one certificate is signed by the other. I don't want to check based on the IssuerName as it is not reliable(for my scenario).

Solution

  • IssuerName property and Authority Key Identifier extension are the way to find relationships between certificates. Once you match them, you can verify if the supposedly parent certificate is actually the CA certificate of the one being checked. I am not sure that such checks are possible with .NET Framework alone, and our SecureBlackbox does this easily, with one method.