Certificate revocation system

Abstract

A method of managing certificates in a communication system having a certifying authority and a directory. Preferably, the method begins by having the certifying authority generate certificates by digitally signing a given piece of data. At a later point time, the certifying authority may produce a string that proves whether a particular certificate is currently valid without also proving the validity of at least some other certificates. The technique obviates use of certification revocation lists communicated between the certifying authority and the directory.

1 .- 23 . (canceled) 
   
   
       24 . A method of validating particular data, comprising:
 providing an initial value;   applying a one-way function to the initial value N times to produce N values, including a final, Nth, value;   digitally signing the Nth value together with the particular data to provide a final value;   providing the final value; and   periodically providing a next previous value to confirm that the particular data is still valid.   
   
   
       25 . A method, according to  claim 24 , further comprising:
 applying a one-way hash function an earliest previous value and comparing a result thereof to the final value.