There are numerous methods and platforms for sharing media with other people, but access control on these platforms requires that you either allow anybody to access the data or you know the people who are going to access the data beforehand. What if you were at a party and you took a video (perhaps of a cake being brought out and the attendees singing happy birthday to the kid whose birthday it is), but your video didn't capture the scene from all the angles that you wanted. Many people are concerned about their privacy, and especially that of their children, so they don't want to make videos like this publicly available. Likewise, it is unlikely that you know everybody at the party, so how could you prove you were there without revealing the video to somebody who might not have also been there?

This is where our Privacy-Preserving Video Sharing (PPVS) system steps in. PPVS uses fully homomorphic encryption (a type of cryptosystem that lets you perform operations on data while it is encrypted and then when you decrypt it, its as if those operations had been performed on the decrypted data) to help ensure that neither person sees the other person's video. Fully Homomorphic Encryption takes a really long time though, especially on a low-power platform like a mobile phone, so we also created a modified version of our extremely fast SSO algorithm that enabled us to detect if the videos were of the same scene, even if they were shot at different angles and distances from different types of phones. Now we are able to determine with very high precision if two videos were of the same event in about one second without revealing information about either video to either party if they aren't of the same scene.