Dynamic Multi-threshold Metering Schemes

A metering scheme is a method by which an audit agency is able to measure the interaction between clients and servers on the web during a certain number of time frames. Naor and Pinkas 7] considered metering schemes in which any server is able to construct a proof to be sent to the audit agency if and only if it has been visited by at least a number, say h, of clients in a given time frame. In their schemes the parameter h is xed and is the same for any server and any time frame. This is acceptable whenever there is a long-term relationship between the audit agency and the servers. In order to measure any number of visits in any granularity we introduce dynamic multi{ threshold metering schemes, which are metering schemes in which there is a threshold h t j associated to any server S j for any time frame t. We mainly focus on the eeciency of dynamic multi{threshold metering schemes, providing lower bounds on the size of the information distributed to clients and to servers (this is important otherwise the task of receiving and sending information would burden the clients, that are not interested in the metering process).