I want to prove that some file I retrieved using HTTPS was indeed sent by the server. I tried searching online, but I didn't find what I want.
How to easily prove that some HTTPS server sent some file? It should not require special permissions and preferably be done with only well-known free software. The proof should be valid as long as the server's certificate is valid. The proof should be able to be validated without internet access.
An example is that the contents of a web page depends on the geographical location of the client. It's something funny when requested from my IP address such as this one. I want to show it to someone else. If I give him the link, he won't get the same page. If I give him the page retrieved from my computer, he'll think I have changed the page. Fortunately, the page is retrieved from the server using HTTPS. If the connection uses a key exchange algorithm in which the server signs the random bytes in ClientHello and ServerHello, I can show him the traffic between the server and my computer. Then he'll believe it's indeed that server which has sent me the page, because only a server that has the private key to the certificate can sign the random bytes.
Or how to easily prove the authenticity of an SSL server to someone else?