Abstract
This paper proposes a cryptographic scheme for metering the duration and/or the number of instances of running a process. This scheme has the following property: knowing a secret, one can validate a piece of metering evidence in constant units of time while without the secret the job of generating a valid piece of evidence requires time indicated by the evidence. Because the scheme utilises a well-known computational complexity problem, the meter based on it can be implemented in software yet is tamper-resistant.
We will address the use of this scheme in building an auditable metering scheme for finding the popularity of web sites. The scheme is suitable for rapidly increasing web advertisement applications. We will also discuss the related security issues.