Abstract

Metering consumption and billing has been a traditional reason to collect, process and store detailed records. Proposed business models and government practices, such as electronic road tolling, pay-as-you-drive-insurance, smart-grids for electricity and even virtualised computing and storage, rely on charging users using even more fine grained information than ever before for their usage and consumption. This is at odds with the privacy consumers have been accustomed to. Current implementation proposals require huge databases of personal information to be built—we show that these are not necessary.

We present protocols for metering and fine grained billing that do not require the collection, processing or storage of personal information. We focus on the example of smart-grids to show how meter readings can be cryptographically transformed by users’ devices to apply a tariff policy, and produce a bill for the utility companies. Using Zero-knowledge techniques our protocols perfectly hide all privacy sensitive information, while protecting the integrity of the bills. We also discuss practical deployment issues and 3 implementations providing different trade-offs in speed, scalability and software correctness.