Google and Tor.

Mike Perry mikeperry at
Thu Aug 26 00:52:20 UTC 2010

Thus spake Matthew (pumpkin at

>  On numerous occasions when using Google with Tor (yes, I know there are 
> other options like Scroogle) it claims I might be sending automated queries 
> and gives me a CAPTCHA.  Sometimes this allows me to search; other times I 
> am caught in a loop and am constantly send back to the CAPTCHA screen.

This has been a known problem with Google for ages. There are numerous
ways we could improve this situation without requiring blanket
exemptions for Tor Exits (such as client side puzzles, or more
intelligent rate limiting algorithms that are more tolerant of our
typically cookieless but legitimate users coming in large masses from
the same IP). 

Unfortunately the DoS team at Google is unwilling to work with us to
find alternate ways of limiting these captchas at the moment. Tor has
many friends inside Google, but sadly the DoS team is independent
enough from the rest of Google that regardles of Google's opinion of
Tor or censorship circumvention, the DoS team is unwilling to devote
any development resources to improving this problem, and have declined
even meeting with us directly :(

Astute students of human nature will note that this is the result you
expect when you place a small group of people in a position of
unassaillable control of a resource for "security reasons"...

Our current solution is to automatically redirect Google Captcha
requests to alternate search engines such as ixquick, scroogle, yahoo,
or bing. This feature was introduced in Torbutton 1.2.5 and uses
ixquick by default. 

However, Google's recent switch to using for SSL
search caused our captcha detection code to break in Torbutton. So if
you are using encrypted search and/or HTTPS Everywhere, your captchas
will no longer be seamlessly redirected.

This should be fixed in Torbutton 1.2.6.

Mike Perry
Mad Computer Scientist evil labs
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