A Taxonomy of Secure Two-Party Comparison Protocols and Efficient Constructions

Attrapadung, Nuttapong; Hanaoka, Goichiro; Kiyomoto, Shinsaku; Mimoto, Tomoaki; Schuldt, Jacob C. N.

doi:10.1109/pst.2017.00033

Cited by 5 publications

(11 citation statements)

References 21 publications

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“…Secure comparison protocols have many variants (cf. [2]); in order to be able to flexibly use them as building blocks in larger applications, it is imperative to consider the variant with shared inputs and shared output. More precisely, the inputs to the protocol are shares of x and shares of y, while the output comprises shares of bit b which indicates the result of comparing x < y (note that it is sufficient w.l.o.g.…”

Section: Secure Comparison Protocolsmentioning

confidence: 99%

“…This enables us to construct the LSB protocol based on a comparison protocol with plain inputs and shared output, called PlainLessThan protocol. -We then construct a protocol for PlainLessThan by using a tree-based structure called dyadic range, similarly to [2]. This has two advantages.…”

Section: Our Contributionmentioning

confidence: 99%

“…As Veugen et al [23] pointed out, secret sharing based secure comparisons [6,11,15] have an advantage in online phase in comparison with garbled circuit based protocols and homomorphic encryption based protocols. Attrapadung et al [2] categorized various secure comparison protocols regarding their input/output forms. Damgård et al [7] proposed a constant-round secure comparison scheme and Nishide-Ohta [15] developed the idea to construct fewer rounds secure comparison protocol, on which our protocol is based.…”

Section: Related Workmentioning

confidence: 99%

“…Our protocol for PlainLessThan is based on binary tree structure, which admits parallel computation (and hence use small constant rounds of communication). This is somewhat related to the protocol in [2], with the difference that here our protocol uses secret sharing, while [2] uses homomorphic encryption. PlainLessThan uses PlainEqual as a subroutine.…”

Section: Outline Of Our Protocol Formentioning

confidence: 99%

“…Intuition/Approach. We construct a protocol for PlainLessThan based on binary-tree-based approach called dyadic range in a similar manner to [2]. The main idea of this tree-based approach is that when the inputs are plain, we can directly "encode" them to a data structure that is suitable for comparison in parallel.…”

Section: Algorithm 4 Plainlessthan Protocolmentioning

confidence: 99%

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Constant-Round Client-Aided Secure Comparison Protocol

Morita¹,

Attrapadung²,

Teruya³

et al. 2018

Computer Security

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We present an improved constant-round secure two-party protocol for integer comparison functionality, which is one of the most fundamental building blocks in secure computation.Our protocol is in the so-called client-server model, which is utilized in real-world MPC products such as Sharemind, where any number of clients can create shares of their input and distribute to the servers who then jointly compute over the shares and return the shares of result to the client. In the client-aided client-server model, as mentioned briefly by Mohassel and Zhang (S&P'17), a client further generates and distributes some necessary correlated randomness to servers. Such correlated randomness admits efficient protocols since otherwise servers have to jointly generate randomness by themselves, which can be inefficient.In this paper, we improve the state-of-the-art constant-round comparison protocols by Damgård et al. (TCC'06) and Nishide and Ohta (PKC'07) in the client-aided model. Our techniques include identifying correlated randomness in these comparison protocols. Along the way, we also use tree-based techniques for a building block, which deviate from the above two works. Our proposed protocol requires only 5 communication rounds, regardless of the bit length of inputs. This is at least 5 times fewer rounds than existing protocols. We implement our secure comparison protocol in C++. Our experimental results show that this low-round complexity benefits in low-latency networks such as WAN.

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Section: Secure Comparison Protocolsmentioning

confidence: 99%

Section: Our Contributionmentioning

confidence: 99%