Performances of Cryptographic Accumulators

International audienceCryptographic accumulators are space/time efficient data structures used to verify if a value belongs to a set. They have found many applications in networking and distributed systems since their in- troduction by Benaloh and de Mare in 1993. Despite this popularity, there is currently no performance evaluation of the different existing de- signs. Symmetric and asymmetric accumulators are used likewise without any particular argument to support either of the design. We aim to es- tablish the speed of each design and their application's domains in terms of their size and the size of the values

An Overview of Cryptographic Accumulators

This paper is a primer on cryptographic accumulators and how to apply them practically. A cryptographic accumulator is a space- and time-efficient data structure used for set-membership tests. Since it is possible to represent any computational problem where the answer is yes or no as a set-membership problem, cryptographic accumulators are invaluable data structures in computer science and engineering. But, to the best of our knowledge, there is neither a concise survey comparing and contrasting various types of accumulators nor a guide for how to apply the most appropriate one for a given application. Therefore, we address that gap by describing cryptographic accumulators while presenting their fundamental and so-called optional properties. We discuss the effects of each property on the given accumulator's performance in terms of space and time complexity, as well as communication overhead.Comment: Note: This is an extended version of a paper published In Proceedings of the 7th International Conference on Information Systems Security and Privacy (ICISSP 2021), pages 661-66

Performances of Cryptographic Accumulators

International audienceCryptographic accumulators are space/time efficient data structures used to verify if a value belongs to a set. They have found many applications in networking and distributed systems since their in- troduction by Benaloh and de Mare in 1993. Despite this popularity, there is currently no performance evaluation of the different existing de- signs. Symmetric and asymmetric accumulators are used likewise without any particular argument to support either of the design. We aim to es- tablish the speed of each design and their application's domains in terms of their size and the size of the values

Cryptographic Key Distribution In Wireless Sensor Networks Using Bilinear Pairings

It is envisaged that the use of cheap and tiny wireless sensors will soon bring a third wave of evolution in computing systems. Billions of wireless senor nodes will provide a bridge between information systems and the physical world. Wireless nodes deployed around the globe will monitor the surrounding environment as well as gather information about the people therein. It is clear that this revolution will put security solutions to a great test. Wireless Sensor Networks (WSNs) are a challenging environment for applying security services. They differ in many aspects from traditional fixed networks, and standard cryptographic solutions cannot be used in this application space. Despite many research efforts, key distribution in WSNs still remains an open problem. Many of the proposed schemes suffer from high communication overhead and storage costs, low scalability and poor resilience against different types of attacks. The exclusive usage of simple and energy efficient symmetric cryptography primitives does not solve the security problem. On the other hand a full public key infrastructure which uses asymmetric techniques, digital signatures and certificate authorities seems to be far too complex for a constrained WSN environment. This thesis investigates a new approach to WSN security which addresses many of the shortcomings of existing mechanisms. It presents a detailed description on how to provide practical Public Key Cryptography solutions for wireless sensor networks. The contributions to the state-of-the-art are added on all levels of development beginning with the basic arithmetic operations and finishing with complete security protocols. This work includes a survey of different key distribution protocols that have been developed for WSNs, with an evaluation of their limitations. It also proposes Identity- Based Cryptography (IBC) as an ideal technique for key distribution in sensor networks. It presents the first in-depth study of the application and implementation of Pairing- Based Cryptography (PBC) to WSNs. This is followed by a presentation of the state of the art on the software implementation of Elliptic Curve Cryptography (ECC) on typical WSNplatforms. New optimized algorithms for performing multiprecision multiplication on a broad range of low-end CPUs are introduced as well. Three novel protocols for key distribution are proposed in this thesis. Two of these are intended for non-interactive key exchange in flat and clustered networks respectively. A third key distribution protocol uses Identity-Based Encryption (IBE) to secure communication within a heterogeneous sensor network. This thesis includes also a comprehensive security evaluation that shows that proposed schemes are resistant to various attacks that are specific to WSNs. This work shows that by using the newest achievements in cryptography like pairings and IBC it is possible to deliver affordable public-key cryptographic solutions and to apply a sufficient level of security for the most demanding WSN applications

Decentralized Anonymous Payments

Decentralized payment systems such as Bitcoin record monetary transactions between pseudonyms in an append-only ledger known as a blockchain. Because the ledger is public, permanent, and readable by anyone, a user’s privacy depends solely on the difficulty of linking pseudonymous transactions either to each other or to real identities. Both academic work and commercial services have shown that such linking is, in fact, very easy. Anyone at any point in the future can download a user’s transaction history and analyze it. In this work, we propose and implement privacy preserving coins, payments, and payment channels that can be built atop a ledger. In particular we propose: * Zerocoin A blockchain based protocol for breaking the link between a transaction that receives non-anonymous funds and the subsequent transaction that spends it. * Zerocash The successor to Zerocoin, a blockchain based payment system supporting anonymous payments of arbitrary hidden value to other parties. While payments are recorded publicly in the blockchain, they reveal almost nothing else: the recipient learns only the amount paid but not the source and anyone else learns only that a payment of some value to someone took place. *Bolt A payment channel protocol that allows two parties to anonymously and securely make many unlinkable payments while only posting two messages to the blockchain. This protocol provides for instant payments while providing drastically improved scalability as every transaction is no longer recorded in the blockchain

analysis of bilinear pairing-based accumulator for identity escrowing

改革开放以来,基层工会工作进入了一个全新的历史时期,作为工会工作重要组成部分的基层工会宣传教育工作同样也面临着新的形势和新的考验。在这样的形势下,基层工会宣传教育工作的理论原则、方针、方法,如何体现与时俱进,真正做到实事求是、指导实践、服务实践,更好地适应工会工作发展的需要

Analysis of bilinear pairing-based accumulator for identity escrowing

An accumulator based on bilinear pairings was proposed at CT-RSA'05. Here, it is first demonstrated that the security model proposed by Lan Nguyen does lead to a cryptographic accumulator that is not collision resistant. Secondly, it is shown that collision-resistance can be provided by updating the adversary model appropriately. Finally, an improvement on Nguyen's identity escrow scheme, with membership revocation based on the accumulator, by removing the trusted third party is proposed