Psiphon Content Delivery Software

URL encryption breaks caching

Reported by root on 2009-10-01
8
This bug affects 1 person
Affects Status Importance Assigned to Milestone
psiphon
Unknown
Adam P

Bug Description

We use CBC mode (random IV mixed into each string encryption) to encode URLs. This means that the same URL will encode differently each time. This means that instead of the same page element getting downloaded only once, regardless of how often it's referenced, it will get downloaded once for each reference.

            For example: On cnn.com, the little red bullet image gets downloaded 33 times instead of one time.

            This causes major inefficiency on the client end, and unnecessary load on our server.

root (n-root-psiphon-ca) wrote :

Note that if we switch to port forwarding we could stop encoding URLs and this problem would go away.

                Alternatively, we could use ECB mode (the same plaintext gets encrypted to the same ciphertext), but that raises some security concerns.

Adam P (adam+) on 2009-10-29
Changed in psiphon:
status: New → Confirmed
Rod (rod-psiphon) on 2009-11-24
visibility: private → public
e.fryntov (e-fryntov) on 2010-05-06
tags: added: category1
Adam P (adam+) wrote :

When closing this, be sure to verify and close bug #457417

Adam P (adam+) wrote :

When closing this, be sure to verify and close Bug #457433

Adam P (adam+) on 2010-06-02
Changed in psiphon:
status: Confirmed → Fix Committed
assignee: nobody → Adam (adam+)
milestone: none → 2.5
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