[OTR-users] QQ is blocking OTR

[Ananda Samaddar]

> It appears that, in spite of a reproducible problem sending ?OTR
> between libpurple-based clients running OTR, Tencent QQ is probably
> not deliberately blocking OTR after all.
> 
> I am the user who initially contacted Ananda to confirm her findings.

I am actually male!  I refer you to my namesake and Ravi Shankar's
nephew, a sadly deceased but amazing sitar player:

http://en.wikipedia.org/wiki/Ananda_Shankar

> In all my tests described herein, separate QQ accounts were used on
> separate computers at different physical locations connecting to the
> Internet with different IP addresses. I was using Pidgin 2.5.0 on
> Xubuntu Linux 8.04. A friend of mine (hereafter to be referred to as
> "my associate") was using Adium X 1.3.2 on Mac OS X 10.5.5 (Intel). My
> OTR plugin was enabled, but set not to automatically initiate OTR
> conversations. Neither of us could send ?OTR to the other. When we
> then tried to actually start an OTR conversation (with either of us
> starting it--we tried it both ways), it would fail silently on my end
> and my associate got the error: "Could not send the last message
> because it was too large."

A quick and dirty test by me has determined that QQ or at least
libpurple's implementation of it has a maximum message size of 500
Latin / English characters.  The test was done by composing messages
with the string Abcdefghijklmnopqrstuvwxyz with no spaces repeated.


> That is what I reported to Ananda. Since then, Ananda and I have
> verified that OTR does not work over QQ (and fails silently) between
> two Linux Pidgin 2.5.0 clients.
> 
> Today my associate and I tried both using Pidgin 2.5.0 on Xubuntu
> Linux 8.0.4. With the OTR plugin turned off, we were able to both send
> ?OTR to one another successfully. With the plugin turned on but set
> not to automatically initiate OTR conversations, neither of us was
> able to do so. We then found that whoever had OTR turned off
> completely was able to receive "?OTR" as an IM.
> 
> We tested it with QQ for Windows, using QQ2005 v05.0.200.020 (English)
> on each end. Mine ran on Windows FLP Version 2006 SP3. My associate
> ran it on Windows XP Professional Version 2002 SP3. We were able to
> send ?OTR in both directions. We tried it with QQ2005 on my end and
> Adium X 1.3.2 on my associate's end, and I was able to receive ?OTR
> (i.e. my associate was able to send it), but my associate was not able
> to receive it (i.e. I was not able to send it). This further bolstered
> the hypothesis that the failure to send ?OTR is actually due to OTR
> not displaying incoming messages that start with that string.

Good to hear but I would recommend removing the official QQ client ASAP
as per my previous warnings about it.


 > Therefore, I believe the explanation that remains is that the recent
> failure of QQ to work with OTR is due to a decrease by Tencent in the
> maximum message size you can send over QQ. This is consistent with the
> Adium error messages, and is an issue that could probably be addressed
> without too much difficulty.
> 

Hopefully this can be implemented quite painlessly

Ananda
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