User data confinement pattern
Avoid the central collection of personal data by shifting some amount of the processing of personal data to the user-trusted environments (e.g. their own devices). Allow users to control the exact data that shares with service providers
This pattern may be used whenever the collection of personal data with one specific and legitimate purpose still pose a relevant level of threat to the users' privacy
The engineering process is biased to develop system-centric architectures where the data is collected and processed in single central entities, forcing users to trust them and share potentially sensible personal data
The solution is to shift the trust relationship, meaning that instead of having the customer trust the service provide to protect its personal data, the service provider now haves to trust the customers' processing.
In the smart meter example, the smart meter would receive the monthly tariff and calculate the customer's bill which will be then sent to the energy provider where it will be processed. The main benefit is that at no moment the personal data has left the users trusted environment.
Avoid the need for trust in service providers and the collection of personal data
Depending on the type of processing (e.g calculate the bill for the monthly energy consumption or the age from the birth date) the service provider will require some guarantees from the processor (the end user). This may involve the usage of Trusted Platform Modules or cryptographic algorithms (e.g. ABC4Trust)
The smart grid is a domain with a clear example: having smart meters delivering hourly customers' energy consumption to the energy provider poses a serious threat to the customers' privacy. If the only purpose of collecting these data is to bill the customer, why cannot this calculation be done by the customer based on pre-established tariffs?
Similar examples in other domains are "pay as your drive" insurance policies where the insurance price is calculated based on the drivers behaviour or electronic toll pricing
Smart meter, Privacy-enhanced attribute based credentials, pay as your drive insurances, electronic toll pricing