6,471 research outputs found
FastPay: High-Performance Byzantine Fault Tolerant Settlement
FastPay allows a set of distributed authorities, some of which are Byzantine,
to maintain a high-integrity and availability settlement system for pre-funded
payments. It can be used to settle payments in a native unit of value
(crypto-currency), or as a financial side-infrastructure to support retail
payments in fiat currencies. FastPay is based on Byzantine Consistent Broadcast
as its core primitive, foregoing the expenses of full atomic commit channels
(consensus). The resulting system has low-latency for both confirmation and
payment finality. Remarkably, each authority can be sharded across many
machines to allow unbounded horizontal scalability. Our experiments demonstrate
intra-continental confirmation latency of less than 100ms, making FastPay
applicable to point of sale payments. In laboratory environments, we achieve
over 80,000 transactions per second with 20 authorities---surpassing the
requirements of current retail card payment networks, while significantly
increasing their robustness
Moving Participants Turtle Consensus
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.Comment: 31 pages, 4 figures, OPODI
Optimal byzantine resilient convergence in oblivious robot networks
Given a set of robots with arbitrary initial location and no agreement on a
global coordinate system, convergence requires that all robots asymptotically
approach the exact same, but unknown beforehand, location. Robots are
oblivious-- they do not recall the past computations -- and are allowed to move
in a one-dimensional space. Additionally, robots cannot communicate directly,
instead they obtain system related information only via visual sensors. We draw
a connection between the convergence problem in robot networks, and the
distributed \emph{approximate agreement} problem (that requires correct
processes to decide, for some constant , values distance
apart and within the range of initial proposed values). Surprisingly, even
though specifications are similar, the convergence implementation in robot
networks requires specific assumptions about synchrony and Byzantine
resilience. In more details, we prove necessary and sufficient conditions for
the convergence of mobile robots despite a subset of them being Byzantine (i.e.
they can exhibit arbitrary behavior). Additionally, we propose a deterministic
convergence algorithm for robot networks and analyze its correctness and
complexity in various synchrony settings. The proposed algorithm tolerates f
Byzantine robots for (2f+1)-sized robot networks in fully synchronous networks,
(3f+1)-sized in semi-synchronous networks. These bounds are optimal for the
class of cautious algorithms, which guarantee that correct robots always move
inside the range of positions of the correct robots
A support architecture for reliable distributed computing systems
The Clouds kernel design was through several design phases and is nearly complete. The object manager, the process manager, the storage manager, the communications manager, and the actions manager are examined
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