CRL last changed extension or attribute

Abstract

A method and apparatus for generating a CRL with a last_changed extension. When sequential CRLs are generated there is the potential that there will be no changes in the data associated with the CRL. In this case a recipient of the new CRL may needlessly perform processing on the new CRL. A CRL consistent with embodiments of the present invention provides an extension to specify the CRL number of the last_changed CRL. This provides the recipient with information to determine whether the new CRL should be processed or the existing data is up to date.

1 .- 16 . (canceled)  
   
   
       17 . A computer readable medium containing a data structure for a digital certificate revocation list (CRL), wherein the data structure comprises: 
 a list of digital certificates satisfying at least one inactive criterion;    a CRL identifier; and    an attribute for indicating whether a CRL is the latest CRL, wherein the CRL is the latest CRL if changes have been made to the list of digital certificates in the CRL compared to the list in a previously generated CRL.    
   
   
       18 . The computer readable medium according to  claim 17 , wherein the CRL identifier comprises a sequentially assigned number.  
   
   
       19 . The computer readable medium according to  claim 17 , wherein the at least one inactive criterion comprises at least one of a hold status criterion, an expired status criterion and a revoked status criterion.  
   
   
       20 . The computer readable medium according to  claim 17 , wherein the attribute of a latest CRL comprises an extension to an ASN.1 standard CRL.