The dining cryptographers protocol implements a multiple access channel in whichsenders and recipients are anonymous. A problem is that a malicious participant can disrupt commu-nication by deliberately creating collisions. We propose a computationally secure dining cryptogra-phers protocol with collision resolution that achieves a maximum stable throughput of 0.924 messagesper round and which allows to easily detect disruptors.
A fully verifiable dining cryptographers protocol was proposed in @cite_0 and rediscovered in @cite_4 . In this protocol, we have 100 which can be lengthy and cumbersome. Current systems are using mixnets to perform the reservations and therefore they are inefficient when only a few reservations are made. Further, they do not easily adapt to situations where participants join or leave frequently.
@cite_0 @cite_4
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Dining cryptographers networks (or DC-nets) are a privacy-preserving primitive devised by Chaum for anonymous message publication. A very attractive feature of the basic DC-net is its non-interactivity. Subsequent to key establishment, players may publish their messages in a single broadcast round, with no player-to-player communication. This feature is not possible in other privacy-preserving tools like mixnets. A drawback to DC-nets, however, is that malicious players can easily jam them, i.e., corrupt or block the transmission of messages from honest parties, and may do so without being traced. Mix-nets are used in e-voting schemes and other applications that require anonymity. Shuffles of homomorphic encryptions are often used in the construction of mix-nets. A shuffle permutes and re-encrypts a set of ciphertexts, but as the plaintexts are encrypted it is not possible to verify directly whether the shuffle operation was done correctly or not. Therefore, to prove the correctness of a shuffle it is often necessary to use zero-knowledge arguments. We propose an honest verifier zero-knowledge argument for the correctness of a shuffle of homomorphic encryptions. The suggested argument has sublinear communication complexity that is much smaller than the size of the shuffle itself. In addition the suggested argument matches the lowest computation cost for the verifier compared to previous work and also has an efficient prover. As a result our scheme is significantly more efficient than previous zero-knowledge schemes in literature. We give performance measures from an implementation where the correctness of a shuffle of 100,000 ElGamal ciphertexts is proved and verified in around 2 minutes. We propose a retrieval-augmented convolutional network and propose to train it with local mixup, a novel variant of the recently proposed mixup algorithm. The proposed hybrid architecture combining a convolutional network and an off-the-shelf retrieval engine was designed to mitigate the adverse effect of off-manifold adversarial examples, while the proposed local mixup addresses on-manifold ones by explicitly encouraging the classifier to locally behave linearly on the data manifold. Our evaluation of the proposed approach against five readily-available adversarial attacks on three datasets--CIFAR-10, SVHN and ImageNet--demonstrate the improved robustness compared to the vanilla convolutional network. Large scale data processing brings new challenges to the design of privacy-preserving protocols: how to meet the increasing requirements of speed and throughput of modern applications, and how to scale up smoothly when data being protected is big. Efficiency and scalability become critical criteria for privacy preserving protocols in the age of Big Data. In this paper, we present a new Private Set Intersection (PSI) protocol that is extremely efficient and highly scalable compared with existing protocols. The protocol is based on a novel approach that we call oblivious Bloom intersection. It has linear complexity and relies mostly on efficient symmetric key operations. It has high scalability due to the fact that most operations can be parallelized easily. The protocol has two versions: a basic protocol and an enhanced protocol, the security of the two variants is analyzed and proved in the semi-honest model and the malicious model respectively. A prototype of the basic protocol has been built. We report the result of performance evaluation and compare it against the two previously fastest PSI protocols. Our protocol is orders of magnitude faster than these two protocols. To compute the intersection of two million-element sets, our protocol needs only 41 seconds (80-bit security) and 339 seconds (256-bit security) on moderate hardware in parallel mode.