April 2, 2003] Fabrice Le Fessant Microsoft Research lab.

We describe the design and implementation of a reputation-aware servent for Gnutella-like peer-to-peer systems.

The Keyword-Set Search System (KSS) is a Peer-to-Peer (P2P) keyword search system that uses a distributed inverted index. The main challenge in a distributed index and search system is finding the right scheme to partition the index across the nodes in the network. The most obvious scheme would be to partition the index by keyword. A keyword partitioned index requires that the list of index entries for each keyword in a search be retrieved, so all the lists can be joined; only a few nodes need to be contacted, but each sends a potentially large amount of data. In KSS, the index is partitioned by sets of keywords. KSS builds an inverted index that maps each set of keywords to a list of all the documents that contain the words in the keyword-set. When a user issues a query, the keywords in the query are divided into sets of keywords. The document list for each set of keywords is then fetched from the network. The lists are intersected to compute the list of matching documents. The list of index entries for each set of words is smaller than the list of entries for each word. Thus search using KSS results in a smaller query time overhead.

The wide qualities of peer-to-peer (P2P) network have given us many advantages and threats for enhancement of distributed computing. The best way to reduce threats is adding a reputation-based globally trusted model. Many present trust models are failing to restrain effectively some behaviors like collusive attacks, but pay no heed towards the security of this mechanism.