

This already exists in theory, although not many companies or products are implementing it: https://en.wikipedia.org/wiki/Content_Authenticity_Initiative
I think Leica cameras can sign their images, but I don’t know if any other cameras support it yet.
OKCupid was alright before the buyout. I won’t say it was great, but I went out with several people thanks to that site and met my current partner of 12 years there.