Privacy-preserving algorithms for distributed mining of frequent itemsets

Standard algorithms for association rule mining are based on identification of frequent itemsets. In this paper, we study how to maintain privacy in distributed mining of frequent itemsets. That is, we study how two (or more) parties can find frequent itemsets in a distributed database without revealing each party's portion of the data to the other. The existing solution for vertically partitioned data leaks a significant amount of information, while the existing solution for horizontally partitioned data only works for three parties or more. In this paper, we design algorithms for both vertically and horizontally partitioned data, with cryptographically strong privacy. We give two algorithms for vertically partitioned data; one of them reveals only the support count and the other reveals nothing. Both of them have computational overheads linear in the number of transactions. Our algorithm for horizontally partitioned data works for two parties and above and is more efficient than the existing solution. (C) 2006 Elsevier Inc. All rights reserved.