A web service for certified email

Web service technology allows the completion of complex tasks through the definition of simpler collaborating services. As soon as Web services become available a challenging problem is the provision of means by which the data exchange and the service usage can be proofed. An interesting test case comes from the development of Web based certified email systems. Tn such systems users exchanging email messages would like to get some additional guarantees on the security of the communication during the interaction. In this work we describe the design and the implementation of a certified email application realized through the definition of interacting servers. Users access the service through a Web based application and are able to get, at the end of the transaction, a valid receipt which can be used in case of dispute.