Let's say I want to prove to someone that a webpage claims X. I could take a screenshot, but it could easily be doctored. However, the webpage's contents are encrypted by the domain using its private key. Is there a way to use the encrypted message to prove to someone that I haven't modified it?
I think this is possible if I generate a temporary private key and use it in the connection, then present it along with the encrypted text. Then, anyone can decrypt the message using my temporary private key, and since I can't encrypt a message without the domain's private key, they can be confident it's authentic.
Is there a way to do this without presenting my private key?