Hello everyone,
I hope you’re all doing well! I wanted to share a recent teaching experience related to
SSL/TLS certificate verification and seek your insights on a particular point of confusion that came up in class.
During a session on secure communications, I had my students test the SSL/TLS configuration of a web server using
OpenSSL. We used the following command to retrieve and display the certificate details:
openssl s_client -connect 192.168.100.30:443 -showcerts
This command successfully connected to the server and displayed the server’s certificate chain. However, one student asked about the process of verifying whether the certificate is valid and trusted, particularly regarding the role of Certificate Authorities (CAs).
To clarify, I explained that the verification process involves checking several factors, including:
- Whether the certificate is signed by a trusted CA.
- The certificate’s expiration date.
- The certificate's revocation status, often checked through OCSP (Online Certificate Status Protocol).
However, I realized I could provide more depth on how to perform these checks effectively. For example, we can check the certificate expiration date using:
openssl x509 -in certificate.crt -noout -dates
I’d love to hear your suggestions on the following:
- How can I effectively demonstrate the entire SSL/TLS verification process in class, including checking the certificate’s revocation status?
- Are there any additional tools or techniques you recommend for teaching about certificate verification and the role of CAs in ensuring secure communications?
Thank you for your insights!
