How Do I Book a Seat Without Revealing My Seat Number?

With the ever increasing number of breaches, we are moving to a world where companies should not hold any personally sensitive information, as it is just too risky. So how could we create a trustworthy system, where someone can show up with a ticket, and where we can trust it, without actually revealing any personal information about where the person has booked their seat?

So how can we generate a receipt of the booking, but not give away your identity, or the details of the booking? Let’s take an example of booking a seat in a theatre at the Edinburgh Festival, and how your privacy can be respected, but where the theatre will trust the ticket.

Booking a ticket

Let’s say there are 100 seats in a theatre, and I want to book one of them, but I don’t want the theatre company to know which seat I’ve booked, or my identity. I also want a receipt of purchase that they can verify my booking. One way would be to get a trusted agent to look after the bookings, but I don’t trust them either. So how can we do this?

Well it can be done with commutative encryption.

The steps would be:

• Initially the theatre company generates 100 receipts for each of the seats, and then encrypts them with its public key.