[mpeg]

I think kwantam's point is that you are merely storing a hash of the resulting file, it proves it existed at a certain datetime, but it doesn't guarantee it wasn't modified (which TLSNotary does, albeit with a trusted third party required)

This wasn't clear from the link, as there was very little technical information provided.

[gill3s]

I get it, and no, nothing proves you didn't modify it. Maybe a solution is to create some king of "witness community" stamping the same page at the same time. It will have diferent hashes each time and the evidence could be stronger in the end

[JoshuaDavid]

If the website uses SSL, would it be possible to prove that the server signed the particular sequence of bytes you received? That doesn't prove that nobody modified the data but it does prove that anyone who did was able to sign things with a key that nobody else should have access to.

[drdeca]

My understanding is that with usual SSL, it seems that one cannot make a proof based on your interaction with the server that you could use to convince a skeptic at some undetermined later time, However, others here have mentioned the tlsnotary idea which, if you are interacting with the person you want to prove it to live while you get the info from the server, then you can. And, if the server supports the TLS-N extension, then you can instead make a proof that should convince arbitrary people later.

[la_fayette]

That is actually a problem. It should be usable inside the deep web.e.g. to proof that i made a purchase at a website and as a second step that my review of thepurchase is real.