The article discusses how to prevent unauthorized access to data or systems by revoking invalid digital certificates. It compares two common methods, Certificate Revocation Lists (CRLs) and Online Certificate Status Protocol (OCSP), and highlights their limitations. The researchers introduce a new way of distributing CRLs in the Grid Monitoring Architecture to ensure timely and robust revocation information. This research was presented at the 3rd IEEE International Symposium on Security in Networks and Distributed Systems (SSNDS-07).