How to protect a link to a video from distribution?

Question

PHP

Good day!
It is planned to sell video materials through the site.
The principle of operation is simple: the user pays on the site and receives a link by e-mail.
You can't protect a video from downloading, that's understandable.
But how can you protect a link from reuse? So that the link that was sent to the buyer did not work for a third party to whom, for example, the buyer forwarded the link?
And at the same time, the link should not be one-time, but should be opened every time, but only for the buyer.
Where to post the video is not important: we can on the services, we can on our server.
Thanks in advance!

Answer 1

For each client, generate a random hash - there will be a link, then on the server side check the client data (token\cookies\session) if everything is correct - give the page, no - give an error. All in my opinion is rather trivial.

Answer 2

For each buyer, generate a unique "signature" of the image by some distortion of the color/frame area. Then, when finding the one who leaked, it will be possible to find out who, even if he writes from the screen to the phone.

Answer 3

For each buyer, generate a unique "signature" of the image by some distortion of the color/frame area. Then, when finding the one who leaked, it will be possible to find out who, even if he writes from the screen to the phone