Secure Audit Logging with Tamper-Resistant Hardware

Secure perimeter schemes (e.g. DRM) and tracing traitor schemes (e.g. watermarking, audit logging) strive to mitigate the problems of content escaping the control of the rights holder. Secure audit logging records the user’s actions on content and enables detection of some forms of tampering with the logs. We implement the Schneier and Kelsey’s secure audit logging protocol [6], strengthening the protocol by using tamper-resistant hardware (an iButton) in three ways: Firstly, our implementation of the protocol works offline as well as online. Secondly, we use unforgeable timestamps to increase the possibilities of fraud detection. Lastly, we generate the authentication keys, core security of Schneier and Kelsey’s protocol on the iButton to alleviate the possibilities of malicious client generating the bad keys. We provide a performance assessment of our implementation to show under which circumstances the protocol is practical to use.