PeerReview: Practical Accountability for Distributed Systems

Authors: Andreas Haeberlen (MPI-SWS), Petr Kouznetsov (MPI-SWS), and Peter Druschel (MPI-SWS)

Paper: http://www.sosp2007.org/papers/sosp118-haeberlen.pdf

How do you detect faults when the system is federated and you can't see all of it? Specifically, how do you detect faults, how do you identify faulty nodes, and how do you convince evidence? Obviously, we need verifiable evidence.

Genera solution: keep a log, have an auditor that periodically inspects the log. Log is a hash chain (to prevent changing the log ex post facto).

Probabilistic log checking allows for scalability (otherwise overhead would be quadratic).

Q: How do you prevent collusion?
A: We used consistent hashing to choose witnesses, then secure routing.

Q: How do you deal with selective processing?
A: (reiterates what said in the talk)

Q: Seems like most appropriate to malicious faults given that it's all the same state machines. Is this useful for failing software?
A: (nothing useful...offline)

Q: (you misrepresented my CATS system...) How do you make logs visible in a secure way?
A: ??? Assume always at least one correct witness node.

Q: Why is non-repudiation work from 70s not applicable?
A: (Not sure what you're saying, offline)