[armchairhacker]

How do you ensure the tampered content isn’t re-hashed? Usually if you’re saving the hash in advance, you can save the whole archived page. Otherwise, you can use a regular archive service then hash the archived page yourself.

The only way I know to ensure an archive isn’t tampered is to re-archive it. If you sent a site to archive.today, archive.org, megalodon.jp, and ghostarchive.org, it’s unlikely that all will be tampered in the same way.

[arboles]

A list of hashes (tuple of [hashed url+date metadata, hashed content]) takes much less disk space than the archive contents themselves. Archive websites could publish the list for all their content so it can be compared against in the future. People would save copies of the list. If you didn't store the list yourself ahead of time, and don't trust a third-party to be "the source of truth", the archive could've uploaded the hashes to the blockchain at archive time:

https://gwern.net/timestamping