WWW page signatures

One way to sign pages on the WWW is using detached signatures: at the bottom of this page, there used to a link to a separate file which contains one or more detached signatures (created with pgp -stab). See below for why it isn't there any more.

What is the purpose of signing www pages?

• author - who wrote the page.
• rating - authors could collect signatures from ratings agencies; a browser could be written that only displays pages approved by one of those agencies.
• time-stamp - when the page was written, again certified by some independent third party.

Limitations and caveats

• images - these can be handled by using a new attribute on the IMG tag which would contain the result of a strong one-way hash such as MD5. Browsers would have to check this, though.
• links - obviously, the documents referred to are outside the scope of the signature.
• there are probably others I haven't thought of
• if the webmaster insists on appending something to every page (such as a disclaimer), it'll never work. That's why my pages aren't signed any more.