CAPTCHA is an acronym for "Completely Automatic Public Turing Test to Tell Computers and Humans Apart". It is a task, that human can easily solve, but computer not.

It is used as a challenge-response to ensure that the individual submitting information is a human and not an automated process. Typically, a captcha is used with form submissions where authenticated users are not necessary, but you want to prevent spam submissions.

hcaptcha is a free, easy-to-use WebService helps enterprises to integrate Captcha into their own business systems. Similar to Google reCaptcha but can be customized and deployment to your private network.

• High Security: using the distorted, bonding, dislocation and random word length, making it difficult to be dismantled, recognition by machine
• High Performance: Based on C/libevent/libgd/memcached, all levels of optimization, upto 500 Requests pre second in single-threaded (120x60 pixels)
• Local Deployment: Similar to Google reCaptcha but can deployment to private network
• Cluster Deployment: Support for large-scale network deployment LVS -> Hooto Captcha Cluster -> Memcached Cluster

s4

LVS -> Hooto Captcha Cluster -> Memcached Cluster

apt-get install gcc g++ libgd2-xpm-dev libevent-dev libmemcached-dev memcached git

yum install gcc gcc-c++ gd-devel libevent-devel libmemcached-devel memcached git

git clone git://github.com/eryx/hcaptcha.git
cd hcaptcha
make
make insall

/opt/hcaptcha/bin/hcaptchad -c /opt/hcaptcha/etc/hcaptchad.conf
Start hcaptcha/1.0.4 [OK]

killall hcaptchad
Signal(15) Stop hcaptcha/1.0.4 [OK]

http://127.0.0.1:9527/hcaptcha/api/image?hcaptcha_token=123&hcaptcha_opt=refresh

• API Request
  URL
  http://127.0.0.1:9527/hcaptcha/api/image
  Parameters (sent via GET)

• API Response

  Content-Type:image/png binary data...

After your page is successfully displaying CAPTCHA image, you need to configure your form to check whether the answers entered by the users are correct.

• API Requset
  URL
  http://127.0.0.1:9527/hcaptcha/api/verify
  Parameters (sent via GET)

• API Response
  The response from verify is a series of strings separated by "\n".
  To read the string, split the line and read each field.

hcaptcha currently returns the following error codes:

false
incorrect-captcha-word

http://ws.hooto.com/hcaptcha/api/image?hcaptcha_token=123&hcaptcha_opt=refresh

• http://www.captcha.ru/
• http://www.google.com/recaptcha/