  We present Moving Participants Turtle Consensus (MPTC), an asynchronous
consensus protocol for crash and Byzantine-tolerant distributed systems. MPTC
uses various moving target defense strategies to tolerate certain
Denial-of-Service (DoS) attacks issued by an adversary capable of compromising
a bounded portion of the system. MPTC supports on the fly reconfiguration of
the consensus strategy as well as of the processes executing this strategy when
solving the problem of agreement. It uses existing cryptographic techniques to
ensure that reconfiguration takes place in an unpredictable fashion thus
eliminating the adversary's advantage on predicting protocol and
execution-specific information that can be used against the protocol.
  We implement MPTC as well as a State Machine Replication protocol and
evaluate our design under different attack scenarios. Our evaluation shows that
MPTC approximates best case scenario performance even under a well-coordinated
DoS attack.

Distributed, Parallel, and Cluster Computing