EMPSI:Efficient multiparty private set intersection(with cardinality)

Multiparty private set intersection(PSI)allows several parties,each holding a set of elements,to jointly compute the intersection without leaking any additional information.With the development of cloud computing,PSI has a wide range of applications in privacy protection.However,it is complex to build an efficient and reliable scheme to protect user privacy.To address this issue,we propose EMPSI,an efficient PSI(with cardinality)protocol in a multiparty setting.EMPSI avoids using heavy cryptographic primitives(mainly rely on symmetric-key encryption)to achieve better performance.In addition,both PSI and PSI with the cardinality of EMPSI are secure against semi-honest adversaries and allow any number of colluding clients(at least one honest client).We also do experiments to compare EMPSI with some state-of-the-art works.The experimental results show that proposed EMPSI(-CA)has better performance and is scalable in the number of clients and the set size.

IXT: Improved searchable encryption for multi-word queries based on PSI

Oblivious Cross-Tags(OXT)[1]is the first efficient searchable encryption(SE)protocol for conjunctive queries in a single-writer single-reader framework.However,it also has a trade-off between security and efficiency by leaking partial database information to the server.Recent attacks on these SE schemes show that the leakages from these SE schemes can be used to recover the content of queried keywords.To solve this problem,Lai et al.[2]propose Hidden Cross-Tags(HXT),which reduces the access pattern leakage from Keyword Pair Result Pattern(KPRP)to Whole Result Pattern(WRP).However,the WRP leakage can also be used to recover some additional contents of queried keywords.This paper proposes Improved Cross-Tags(IXT),an efficient searchable encryption protocol that achieves access and searches pattern hiding based on the labeled private set intersection.We also prove the proposed labeled private set intersection(PSI)protocol is secure against semi-honest adversaries,and IXT is-semi-honest secure(is leakage function).Finally,we do experiments to compare IXT with HXT.The experimental results show that the storage overhead and computation overhead of the search phase at the client-side in IXT is much lower than those in HXT.Meanwhile,the experimental results also show that IXT is scalable and can be applied to various sizes of datasets.