Towards Privacy-Preserving Multi-party Bartering

A Privacy-Preserving Protocol for the Kidney Exchange Problem

“…We review three existing gate functionalities which we use in our newly developed protocols. The complexities of their implementations are given in Table 1 [21]). Let each party (∀ ∈ P) hold the two encrypted integers and .…”

“…As shorthand notation for the subsequent execution of gate ρ Mult we use ρ UFI-Mult (Unbound Fan In Multiplication) as introduced in [21].…”

“…De nition 2.3 (G LT : Secure Less-an Comparison [21]). Let each party P i (∀i ∈ P) hold the two encrypted integers x and .…”

“…In [21] the author presents a gate for secure comparison in the semi-honest model that provides for shared output, i.e., each party receives a bit such that the XOR of all these bits yields the output bit b. However, it is trivial to modify this gate such that it provides each party with an encrypted output bit b without revealing any information on b and thus implementing functionality G LT .…”

“…In contrast to these two approaches, in the case of a privacy-preserving kidney exchange protocol, the set of commodities, which corresponds to the patients' and donors' medical data, has to remain private. Wüller et al [21,[23][24][25][26] propose several SMPC protocols for multi-party bartering that vary w.r.t. the level of security they provide, the trade structures that can be computed, and their performance.…”