ar X iv : 0 71 0 . 54 25 v 1 [ cs . C R ] 2 9 O ct 2 00 7 Fuzzy Private Matching ( Extended

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 fuzzy, and is useful, for instance, when elements may be inaccurate or corrupted by errors. We consider the fuzzy private matching problem, in a semihonest 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. [1] is incorrect. Subsequently we present two fuzzy private matching protocols. The first, simple, protocol has bit message complexity O(n ` T