Patent ID: 7117182

Claim:
A method for carrying out a multi-party transaction between at least a first party, a second party and a third party in which at least said third party has private information, the method comprising: using at least one computer to perform the steps comprising: determining a first role and a second role which said first and second parties, respectively, will take in the transaction; determining what information about said third party is needed for said first role, and what information about said third party is needed for said second role in order to complete the corresponding role of the transaction; selecting one or more unique identifiers selected from the group consisting of nonces, GUIDs, or other tokens, either before or after either of the determining steps, to represent said third party in the course of the transaction without exposing any of said private information to any of said first or second party beyond what is required to fulfill that party's role in the transaction; providing said first party and said second party with a first subset and a second subset of said private information, respectively, and at least one of said selected unique identifiers, wherein said first and second subsets are based on said information needed for said first and second roles, respectively, and differ from one another at least in part; and an execution step, in which said first and second parties to the transaction complete the transaction, using the first and second subsets of the private information, respectively, without exposure thereof to one another, and said selected unique identifiers, to determine and communicate the details of the fulfillment of their respective roles while minimizing the amount of unneeded private information that is transmitted or otherwise exposed.