Abstract: P2P(Peer-to-Peer) full text search utilizes resources of many peers, it is important to control the scope of peers involved in a search request Considering the requirements of security in full text search, SON(Secure Overlay Network) was proposed for organizing peers into overlay network according the domination of their security level. In SON, a search request of a peer should be transferred down to peers it can dominate. So the peers involved in a search request are only a subset of peers of the overly network, and the search result should accord with the security police certainly. Definition of SON was given and its properties were analyzed. Principle of P2P full text search based on SON and its security problems were discussed. The experiments show that P2P full text search based on SON is efficient.

Key words: Secure overlay network(SON) , Peer-to-Peer(P2P) , Full text search