We are going to introduce Captcha to are web site, an trying to decide which is the best Captcha API to use.
I looked at reCaptcha A remote web-service based solution. But we don't control it, its hosted elsewhere, problems with it going down, and also they use dictionary words, and OCR's task is much simplified - even if it fails to recognize a letter or two it just looks up the most resembling
word from a dictionary.
I looked at SimpleCaptcha simple to use, but according to the forums no longer supported and maintained, looks like its been replaced by Kaptcha.
kaptcha is a modern version of the simplecaptcha project The captchas from it appeared really hard to recognize by OCR, and were human readable too.
JCaptcha the most popular bit does not mean its the best. Its well documented for that reason I would consider using it, but there has been mention that its no longer supported. Provides liberies allowing you to build your own custom Captchas. But have read that its slower in generating an building the check image.
So am torn between using kaptcha and JCaptcha, they both look easy to implement. But seem to generate similar images easy to read by humans not by OCR's . Seem to be framework friendly both can be injected via spring.
The web site in question uses Spring MVC.
If anyone has any views on which they think is better I would welcome any input.
Thanks Tony