Paper 2007/363

Fuzzy Private Matching (Extended Abstract)

Łukasz Chmielewski and Jaap-Henk Hoepman


In the private matching problem, a client and a server each hold a set of $n$ input elements. The client wants to privately compute the intersection of these two sets: he learns which elements he has in common with the server (and nothing more), while the server gains no information at all. In certain applications it would be useful to have a private matching protocol that reports a match even if two elements are only similar instead of equal. Such a private matching protocol is called \emph{fuzzy}, and is useful, for instance, when elements may be inaccurate or corrupted by errors. We consider the fuzzy private matching problem, in a semi-honest environment. Elements are similar if they match on $t$ out of $T$ attributes. First we show that the original solution proposed by Freedman et al. is incorrect. Subsequently we present two fuzzy private matching protocols. The first, simple, protocol has bit message complexity $O(n \binom{T}{t} (T \log{|D|}+k))$. The second, improved, protocol has a much better bit message complexity of $O(n T (\log{|D|}+k))$, but here the client incurs a $O(n)$ factor time complexity. Additionally, we present protocols based on the computation of the Hamming distance and on oblivious transfer, that have different, sometimes more efficient, performance characteristics.

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Cryptographic protocols
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Published elsewhere. Unknown where it was published
fuzzy matchingsecure 2-party computationsecret sharing
Contact author(s)
lukaszc @ cs ru nl
2007-10-26: last of 3 revisions
2007-09-13: received
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      author = {Łukasz Chmielewski and Jaap-Henk Hoepman},
      title = {Fuzzy Private Matching (Extended Abstract)},
      howpublished = {Cryptology ePrint Archive, Paper 2007/363},
      year = {2007},
      note = {\url{}},
      url = {}
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