[tor-bugs] #32047 [Circumvention/Obfs4]: Sharing Keys Through HTML?
Tor Bug Tracker & Wiki
blackhole at torproject.org
Sat Oct 12 05:00:51 UTC 2019
#32047: Sharing Keys Through HTML?
----------------------------+-------------------------------------
Reporter: Aphrodites1995 | Owner: (none)
Type: enhancement | Status: new
Priority: Medium | Component: Circumvention/Obfs4
Version: | Severity: Normal
Keywords: | Actual Points:
Parent ID: | Points:
Reviewer: | Sponsor:
----------------------------+-------------------------------------
If you read how RSA works, it is obvious that decrypting something that is
not meant to be decrypted still works to get random digits that are
similar length. Here, an idea would be to hide some random digits in HTML,
for example into the first hundred colors in <style> or counting the
number of letters inside the first fifty <p>s. These are numerical fields
inside HTML that could have a string, encrypted by a Preshared RSA key
(people know both the private and public key), put into it to be hidden.
People will then decrypt that to get a public key to do the key sharing.
While the censor cannot distinguish a regular HTML and a keysharing HTML
because decrypting any regular HTML also gets you a salted public key,
because both look like nothing. This is weak on its own because the censor
could easily try to decrypt anything with the gotten key that originates
from the requesting address, and if it works it is a tor connection, but
at the same time, with two different connections originating from
different addresses (could be two connections to WiFi to get different
port forwarding), it is difficult for the censor to check every single
connection against each HTML file for the key across the same public IP. I
believe that obfs4 has this problem with the keysharing which reveals that
it is a obfs4 connection.
--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/32047>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
The Tor Project: anonymity online
More information about the tor-bugs
mailing list