Secure Logging as a Service Using Reversible Watermarking

Logs are very important as they provide details of a systems past events as well as help in system monitoring, troubleshooting and forensics. In order to be useful the logging process must be done in a secure manner and logging files must be kept secure for an extended period of time as they may contain sensitive information. However, deploying a logging infrastructure is an expensive and time-consuming task. A natural solution to this problem these days is to use cloud storage for keeping logs, because of the benefits provided by cloud computing thus delegating the log management to a cloud service provider (CSP). This paper introduces secure log as a service using reversible watermarking (SecLaaS-RW) scheme. Reversible watermarking is a type of fragile watermarking, which can be used for content authentication. The content in our case are outsourced logs, to which reversible watermarking is applied. Log records are collected using syslog, processed at the logging server and then transferred to an outsource cloud storage, where all records are saved for extended period of time. We have made comparison with a recently proposed scheme. Our experimental results suggest that with a very limited and manageable overhead per log entry, modifications in the outsourced logs can be detected.