Patent ID: 7694126

Claim:
A method for verifying a first log entry for a corresponding first message included in a first log comprising a plurality of log entries, wherein each log entry includes a hash value (H msg ) determined from a message corresponding to said each entry, wherein said each log entry further includes a hash value (H log ) determined from a previous log entry, wherein said each log entry further includes a signature value determined from the hash values H msg and H log , wherein one or more log entries among log entries P l to P k are checkpointed, the method comprising operating a computer to perform steps of: receiving information for a log entry P j having a corresponding message M j ; determining an index m, where l≧m≧k and m>j; determining a hash value H by applying a hashing function on log entries P j to P m−1 ; judging whether the hash value H is equal to a hash value associated with a subsequent log entry; and outputting a result of the judging step.