reCAPTCHA, Google front end servers and China

[Mikko Ohtamaa]

Hi,

I am running a service where we have customers in China. We use reCAPTCHA to keep many kinds of bots in line and limit the attacks against our service. We have been very happy with the product.

Apparently reCAPTCHA has migrated to Google front end servers in some point, as we have started to get feedback from our Chinese users that the CAPTCHA does not work (as it cannot load JS files from Google servers). Google front end servers are blocked and/or greatly slowed down by the great firewall of China. Maybe it was working before by the chance, maybe the servers where not the Google public front end servers before. However, we'd like to keep using the product if it is possible. I have also witnessed the China issue with other services before, e.g. when hosting Python packages on Google Code and those where not accessible from China.

I am asking for the advice how to mitigate the issue

- Is there a way to proxy reCAPTCHA requests somehow through our front-end servers, so that Chinese users would not need to face Google servers? I am pretty sure reCAPTCHA is doing some logic related to user IP addresses, so this surely would mess it up. Thus I'd like to hear an opinion of actual reCAPTCHA developer here.

- If this is not possible (which I suspect) what alternatives there are for reCAPTCHA we could use for verifying Chinese humans?

Thanks,
Mikko

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