how is the tamper-proof feature guaranteed?

[mikeatm]

I have been looking into tamper-evident audit/logging mechanisms for systemd/syslog, and your product
seems to make a very interesting claim, tamper-proof. how is this done exactly, is there any relation to the work of crosby (http://tamperevident.cs.rice.edu/Logging.html)?
This in my opinion is a rather novel feature, and if it is as you say should be more prominently stated, and explained in docs/faq.