Beer drinking and deep confidentiality may sound like two opposing arguments, but in reality there is a project under way with hooligan registrations using “Secure Multiparty computation”, or SMC for short. in-depth explanation of SMC (in danish)
The scope of the project is to allow restaurateurs to look up if a person is registered in “banned from drinking” database, without being able to see where law abiding citizens go to drink. I think it looks like a interesting project with far reaching consequences for people’s privacy. My interest got stirred by this article (in danish)
The purpose of SMC is to be able to compute more than one input without knowing more than one, it is a part of cryptography known as the ”millionaires problem”. SMC allows you to compute a function without knowing all the input variables, for example you can have two computers that must compute the sum of two numbers, but do not wish to store any of the two numbers on any one machine. Another real world application is in auctions, to deduce who is the highest bidder without knowing who is bidding what.
It is my opinion that this technology will give people access to conclusions and summary on detailed digital information without being exposed to sensitive data, and also hiding the terms of the search or look-up.
Read more in general at Wikipedia (English)