tools for downloading software + automatically verifying integrity

Question

(moved here from a combined question)

I'm wondering if there are any software tools projects to:

• create a standard machine-readable format for publishing a small metadata set = (download link + MD5 hash + optional public key and/or certificate)
• plus a browser plugin (preferably Firefox) to automatically read that data and assist in the steps of
  • downloading the software,
  • verify the downloaded software's integrity
  • add an entry to a log including this information along with what page the software was downloaded from.

I know I manually generate the MD5 and compare the MD5 hash, but it's a very repetitive series of steps that can be error prone, and computers are great at automating things like this.

update: @cynoclast's answer got me curious and I ran across this bugtrack item in DownThemAll and this microformat and this firefox idea, which at least leads me to believe other people are also thinking along these lines.

Answer 1

DownloadThemAll

It's a firefox plugin: