On the (limited) power of non-equivocation

Clement, Allen; Junqueira, Flavio; Kate, Aniket; Rodrigues, Rodrigo

doi:10.1145/2332432.2332490

Cited by 46 publications

(52 citation statements)

References 13 publications

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“…Alternatively, one can assume a constant number of synchronous communication rounds after the synchronization point and run constant expected round synchronous agreement protocols [31]. -Non-equivocation Mechanism: In [18,2] it is shown how to design agreement protocols with t < n/2 in an asynchronous setting, provided there is a mechanism to enforce "non-equivocation". On a very high level, such a mechanism prevents a corrupted party to transmit conflicting messages to honest parties; however a corrupted party may send messages to certain number of parties and decide not to communicate to the rest of the parties.…”

Section: Realizing F Prep With Abort In the Partial Synchronous Setmentioning

confidence: 99%

“…So such a mechanism is strictly weaker than the broadcast primitive. In [18,2] it is also discussed how such a non-equivocation mechanism can be securely realized assuming a trusted hardware module with each party. One can use such a non-equivocation mechanism to agree about the status of Π PREP .…”

Section: Realizing F Prep With Abort In the Partial Synchronous Setmentioning

confidence: 99%

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Linear Overhead Optimally-Resilient Robust MPC Using Preprocessing

Choudhury

Orsini

Patra

et al. 2016

Lecture Notes in Computer Science

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Abstract. We present a new technique for robust secret reconstruction with O(n) communication complexity. By applying this technique, we achieve O(n) communication complexity per multiplication for a wide class of robust practical Multi-Party Computation (MPC) protocols. In particular our technique applies to robust threshold computationally secure protocols in the case of t < n/2 in the pre-processing model. Previously in the pre-processing model, O(n) communication complexity per multiplication was only known in the case of computationally secure non-robust protocols in the dishonest majority setting (i.e. with t < n) and in the case of perfectly-secure robust protocols with t < n/3. A similar protocol was sketched by Damgård and Nielsen, but no details were given to enable an estimate of the communication complexity. Surprisingly our robust reconstruction protocol applies for both the synchronous and asynchronous settings.

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Section: Realizing F Prep With Abort In the Partial Synchronous Setmentioning

confidence: 99%

Section: Realizing F Prep With Abort In the Partial Synchronous Setmentioning

confidence: 99%

Linear Overhead Optimally-Resilient Robust MPC Using Preprocessing

Choudhury

Orsini

Patra

et al. 2016

Lecture Notes in Computer Science

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“…In particular, these systems employ transferable non-equivocation, which (similar to digital signatures) allows a party to verifiably transfer a non-equivocation tag (or signature) provided by a sender to other parties. Clement et al [CJKR12] justify the necessity of transferability of non-equivocation by proving that non-equivocation or signature alone are powerless in asynchronous distributed systems. Nevertheless, (transferable) non-equivocation has not been formalized so far, and we present a simplified, idealized definition for transferable non-equivocation.…”

Section: Definitionsmentioning

confidence: 99%

Asynchronous MPC with a strict honest majority using non-equivocation

Backes

Bendun

Choudhury

et al. 2014

Proceedings of the 2014 ACM Symposium on Principles of Distributed Computing

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Multiparty computation (MPC) among n parties can tolerate up to t < n/2 active corruptions in a synchronous communication setting; however, in an asynchronous communication setting, the resiliency bound decreases to only t < n/3 active corruptions. We improve the resiliency bound for asynchronous MPC (AMPC) to match synchronous MPC using non-equivocation.Non-equivocation is a message authentication mechanism to restrict a corrupted sender from making conflicting statements to different (honest) parties. It can be implemented using an increment-only counter and a digital signature oracle, realizable with trusted hardware modules readily available in commodity computers and smartphone devices. A non-equivocation mechanism can also be transferable and allow a receiver to verifiably transfer the authenticated statement to other parties. In this work, using transferable non-equivocation, we present an AMPC protocol tolerating t < n/2 faults. From a practical point of view, our AMPC protocol requires fewer setup assumptions than the previous AMPC protocol with t < n/2 by Beerliová-Trubíniová, Hirt and Nielsen [PODC 2010]: unlike their AMPC protocol, it does not require any synchronous broadcast round at the beginning of the protocol and avoids the threshold homomorphic encryption setup assumption. Moreover, our AMPC protocol is also efficient and provides a gain of Θ(n) in the communication complexity per multiplication gate, over the AMPC protocol of Beerliová-Trubíniová et al. In the process, using non-equivocation, we also define the first asynchronous verifiable secret sharing (AVSS) scheme with t < n/2, which is of independent interest to threshold cryptography.

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“…Clement et al [8] formally prove that both non-equivocation and transferable authentication are required to reduce BFT replication cost to 2 f + 1. Transferable authentication is necessary because in a 2 f + 1 replica group, in the worst case, only one correct replica has the correct protocol message.…”

Section: Related Workmentioning

confidence: 99%

“…Transferable authentication is also required: each node must be able not only to authenticate a message from another node, but also to forward the message to a third node that will also be able to authenticate it. This requirement was recently formally proven by Clement et al [8]. What this means in practice for this class of protocols is that their trusted components require expensive digital signatures for attestation (the MAC-based authenticators pioneered in PBFT [4] are not sufficient).…”

Section: Introductionmentioning

confidence: 99%

Machine fault tolerance for reliable datacenter systems

Zhuo

Zhang

Ports

et al. 2014

Proceedings of 5th Asia-Pacific Workshop on Systems

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Although rare in absolute terms, undetected CPU, memory, and disk errors occur often enough at datacenter scale to significantly affect overall system reliability and availability. In this paper, we propose a new failure model, called Machine Fault Tolerance, and a new abstraction, a replicated writeonce trusted table, to provide improved resilience to these types of failures. Since most machine failures manifest in application server and operating system code, we assume a Byzantine model for those parts of the system. However, by assuming that the hypervisor and network are trustworthy, we are able to reduce the overhead of machine-fault masking to be close to that of non-Byzantine Paxos.

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On the (limited) power of non-equivocation

Cited by 46 publications

References 13 publications

Linear Overhead Optimally-Resilient Robust MPC Using Preprocessing

Linear Overhead Optimally-Resilient Robust MPC Using Preprocessing

Asynchronous MPC with a strict honest majority using non-equivocation

Machine fault tolerance for reliable datacenter systems

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