http://i3xi5qxvbrngh3g6o7czwjfxwjzigook7zxzjmgwg5b7xnjcn5hzciad.onion/proposals/159-exit-scanning.html
Scanning methodology:
The first scans to be implemented are HTTP, HTML, Javascript, and
SSL scans.
The HTTP scan scrapes Google for common filetype urls such as exe, msi,
doc, dmg, etc. It then fetches these urls through Non-Tor and Tor, and
compares the SHA1 hashes of the resulting content.