Decentralized Auction
The first PACE-oriented project was to build a decentralized auctioning prototype and to examine how and to what extent PACE enabled trust management in this domain.
Domain Description - In a decentralized auctioning system, there is no trusted central authority that controls and coordinates auctions between the sellers and buyers. Instead sellers advertise their products, and buyers directly place their bids with the sellers. Similarly, buyers can advertise any products they want and sellers submit their quotes to the buyers.
Problems/Threats - The main threat to peers in such a decentralized auction is posed by fraudulent sellers and buyers whose identity and history may not be directly known and who may make false claims about fulfilling their part of a transaction. Querying other peers who may have interacted with these buyers or sellers may help a peer determine whom to trust, but this then raises the issue of whether the peers being queried can be trusted in the first place to report correct information.
 |
"Decentralized Auctioning in PACE" |
Implementation Details - In this decentralized auction prototype, each buyer and seller peer is built as a separate instance of the PACE architecture. Both buyers and sellers can advertise products that they are willing to buy and sell. Advertisements for auctions include a URL where bids may be submitted. This URL can refer to the peer itself or to a trusted third-party that will manage the auction on the seller’s behalf. Every peer has a unique public-private key pair that identifies it and is also used for message authentication.
Upon interacting with a fraudulent peer, a peer warns others in the system explicitly by broadcasting messages with appropriate trust values. Every peer in the system uses the same trust model and policy component to enable a uniform comparison of trust values throughout the system. A simplistic partially-transitive trust model is used to compute trust values and determine the trustworthiness of any peer. This trust model only trusts information received from explicitly trusted peers in order to address the issue of incorrect trust information being reported.