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Indexed at: search.filters.indexed.ScopusSubject: search.filters.subject.Cryptography

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    PublicationOpen Access
    Linear complexity private set intersection for secure two-party protocols
    (Springer, 2020) Karakoç, Ferhat; Department of Computer Engineering; Küpçü, Alptekin; Faculty Member; Department of Computer Engineering; College of Engineering; 168060
    In this paper, we propose a new private set intersection (PSI) protocol with bi-oblivious data transfer that computes the following functionality. The two parties (P1 and P2) input two sets of items (X and Y, respectively) and one of the parties (P2) outputs fi(bi) for each yi∈ Y, where bi is 0 or 1 depending on the truth value of yi∈ ? X and fi is defined by the other party (P1) as taking 1-bit input and outputting the party’s (P1’s) data to be transferred. This functionality is generally required when the PSI protocol is used as a part of a larger secure two-party secure computation such as threshold PSI or any function of the whole intersecting set in general. Pinkas et al. presented a PSI protocol at Eurocrypt 2019 for this functionality, which has linear complexity only in communication. While there are PSI protocols with linear computation and communication complexities in the classical PSI setting where the intersection itself is revealed to one party, to the best of our knowledge, there is no PSI protocol, which outputs a function of the membership results and satisfies linear complexity in both communication and computation. We present the first PSI protocol that outputs only a function of the membership results with linear communication and computation complexities. While creating the protocol, as a side contribution, we provide a one-time batch oblivious programmable pseudo-random function based on garbled Bloom filters. We also implemented our protocol and provide performance results.
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    PublicationMetadata only
    Privacy-preserving reputation management in fully decentralized systems: challenges and opportunities
    (Springer Nature, 2019) Tran, Ngoc Hong; Nguyen, Binh Quoc; N/A; Bahri, Leila; Researcher; Graduate School of Sciences and Engineering; N/A
    Reputation is one of crucial personal information strongly attached to each person, so it affects directly to its owner in whatever way it is used. Any form of reputation violation can carry a serious consequence to its owner. Therefore, reputation needs to be managed in a secure way. Moreover, reputation management is a substantial process as it plays a key role in building up a certain trust level, among just-met users. Thus just-met users can base on reputation scores to make a decision on starting up their communication. In addition, reputation management reduces risks of leaking user privacy and losing data security. So far, several works on managing reputation in online social network have been studied, mostly using the Internet for data transmission. In this work, reputation management is placed into the context of fully decentralized environment. Under the more harsh conditions which the decentralized mobile environment carries, such as no central node, frequently changed user location, and restrictions of energy, power, memory, etc., and the security requirement, methods of reputation management get more challenged. Various security problems of managing reputation are still open to be solved. In this work, we make a discussion about recent works on privacy-preserving reputation management in a decentralized environment. We then present challenges, and conclude the open problems as well as possible solutions in reputation management.