US Patent 7770032 Secure logging for irrefutable administration

A method for protecting sensitive data in an entry of a log file for later audit, which includes encrypting the sensitive data in the log entry by using a random cryptographic key for each auditor authorized to access the log entry, encrypting the random cryptographic key by using an auditor's personal cryptographic key, and for each auditor not authorized to access the log entry, encrypting a fake cryptographic key having the same properties as the random cryptographic key by using an auditor's personal cryptographic key.