The purpose of the simple java captcha project is to make it easy to generate good-looking captchas with a minimum of programming and preferably little configuration.
SimpleCaptcha is an open Source Java implementation for captcha creation. Integration is left to the developers of the individual projects because I don't (want) to know your implementations...
My original interest for the thing was after a distributed dictionary attack against one of our systems. Just to make it a little harder we put a quick hack of a picture on the site. The thing was configured so it would only enable itself when an x amount of logins would have failed over an y amount of time. Unfortunately this was found too confusing.
an example:
With the initial drop on source forge the simplecaptcha implementation
can render different jpeg captchas with
configurable:
- background colors
- background gradient fill colors
- fonts (2 default and limited to the amount of font's on your system)
- font color
- random character generator (characters can be configured)
- first name generator (5000 + first Names)
- optional border around the captcha
- border color (defaults to black)
- border thinness (defaults to one)
with the second drop there is:
- a new distortion algorithm (shadowgimpyImp)
- a Chinese captcha
- somewhat more documentation
with the third drop there was:
- a new distortion algorithm (FishEye).
- improvements to the default captcha
some more examples:
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Image generated with the fiveletterFirstName generator. |
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Image generated with random character generator with 6 chars per captcha |
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same but with different font and background colors |
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etc. |
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or with the ShadowGimpyImp |
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with a simplified Chinese word producer |
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FishEye distrotion applied to captcha |