// Load the certificate from a file string certPath = "path/to/cert.pfx"; string certPassword = "password"; X509Certificate2 cert = new X509Certificate2(certPath, certPassword); // Verify the certificate bool isValid = cert.Verify(); // Check if certificate is unexpired and signed by a trusted CA bool isValidWithRevocationCheck = cert.Verify(true); // Check with revocation checkIn this example, we load a certificate from a file (in pkcs12 format) and then use the Verify method to check its validity. We use two different Verify calls, one without revocation check and another with revocation check. This code example uses the X509Certificate2 class from the System.Security.Cryptography.X509Certificates namespace.