Abstract: A method and system for electronic commerce that can prevent personal information (a real profile) from leaking to society. The electronic commerce system is structured in such a manner that a user transmits a transaction request, to which user ID information is added, to a shop system. The shop system then transmits a job order relating to the transaction request to a related business system together with the user ID information. The related business system then transmits requests conversion of the received user ID information to the real profile from a profile conversion system and the profile conversion system reads the real profile information corresponding to the user ID information from a database and transmits an answer to a business system related to the conversion request issuing source using encrypted communication and/or communication by a private line.

Abstract: A system for intermediating selling and purchasing goods and/or services using a network to which a purchaser terminal that transmits offer information including offer conditions from a purchaser and a seller terminal that transmits sales information including sales conditions from a seller are connected. A sales information registering unit registers the sales conditions and a sales information search unit searches, in the sales information registering unit, the sales conditions matching with the offer conditions and outputs a purchasing result to the purchaser terminal. An offer information registering unit registers the offer conditions when the purchasing result indicates that either the sales conditions match with the offer conditions and a notice from the purchaser indicates non-agreement to the purchasing result, or the sales conditions do not match with the offer conditions.