I have a web based bookings system built for a UK higher education client to allow students to sign out equipment (laptops, camera's etc). It's been in use successfully for a couple of years, in the current workflow equipment is collected and the booking is printed, signed by the student and kept until the equipment is returned. They are emailed a pdf copy of the booking and reminders if equipment is outstanding.

Students can login and prebook equipment using their university LDAP credentials, the booking is then authorised by staff for later collection, but can also walk in and have equipment booked out by staff. They would like to remove the signed paper part of the process and replace this with some sort of digital signature. The suggestion was a graphics tablet but with a web based system this would require a local software package and in my view be impractical.

My thought is that students would enter their LDAP username and password upon collection of the equipment, verifying their identity and effectively digitally signing the booking.

My question is what would be best to store as a signature or whether to simply authenticate the user and use a boolean flag to indicate that this has been done could be deemed sufficient?