You would need a way of verifying that the SHA256 is a true copy of the site at the time though and not a faked page. You could do something like have a distributed network of archives that coordinate archival at the same time and then using the SHA256 then be able to see which archives fetched exactly the same page at the same time through some search functionality. I mean if addons are already being used for doing the crawling then we may be mostly there already since said addons would just need to certify their archive and after that they can discard the actual copy of the page. You need need a way to validate those workers though since a bad actor could just run a whole bunch at the same time to legitimise a fake archival.
adespoton@lemmy.ca 1 day ago
The idea is to verify the archival copy’s URL, not to verify the original content. So yes, a server could push different content to the archiver than to people, or vary by region, or an AitM could modify the content as it goes out to the archiver. But adding the sha256 in the URL query parameter means that if someone publishes a link to an archive copy online, anyone else using the link can know they’re looking at the same content the other person was referencing.
If the archive content changes, that URL will be invalid; if someone uses a fake hash, the URL will be invalid (which is why MD5 wouldn’t be appropriate).
The beauty of this technique is that query parameters are generally ignored if unsupported by the web server, so any archival service could start using this technique today, and all it would require is a browser extension to validate the parameter.
Link it to something like Web of Trust, and you’ve solved the separate issue you described.
In fact, this is a feature WoT could add to their extension today, and it would “Just Work”. For that matter, Archive.org could add it to their extension today, too.