Verifiable Photo Snapshots

Abstract

In the age of digital media, photos, videos, and various other media types are widely available and accessible by anyone. Each capture of such media usually includes metadata about when the media was captured, the location of the capture, etc. On many occasions, the capture date of the media becomes a relevant factor in determining whether or not the media can or can not be used to base some claims on. However, the media itself and the associated metadata is easily modifiable by anyone. In case of rental services, e.g., motor vehicle rental, apartment renting, and various others, it is in the interest of both the owner and the renter that the rented item doesn’t get damaged. If, however, it does happen that the item gets damaged, it is not straightforward for a third party to say who caused it. The owner can claim that the renter caused the damage, and the renter can argue that the damage was there before. Such a dispute could be avoided if either the owner or the renter made a photo of the rented item during the handover. In this thesis, we will analyse how to prove the capture date of the photo media type. We will present existing partial and alternative ways of achieving this goal and offer a new solution that would provide a reasonable cryptographic guarantee so that owner nor the renter could claim a false statement.