| Constant | Description | Default |
| kaptcha.border | Border around kaptcha. Legal values are yes or no. | yes |
| kaptcha.border.color | Color of the border. Legal values are r,g,b (and optional alpha) or white,black,blue. | black |
| kaptcha.border.thickness | Thickness of the border around kaptcha. Legal values are > 0. | 1 |
| kaptcha.image.width | Width in pixels of the kaptcha image. | 200 |
| kaptcha.image.height | Height in pixels of the kaptcha image. | 50 |
| kaptcha.producer.impl | The image producer. | com.google.code.kaptcha.impl.DefaultKaptcha |
| kaptcha.textproducer.impl | The text producer. | com.google.code.kaptcha.text.impl.DefaultTextCreator |
| kaptcha.textproducer.char.string | The characters that will create the kaptcha. | abcde2345678gfynmnpwx |
| kaptcha.textproducer.char.length | The number of characters to display. | 5 |
| kaptcha.textproducer.font.names | A list of comma separated font names. | Arial, Courier |
| kaptcha.textproducer.font.size | The size of the font to use. | 40px. |
| kaptcha.textproducer.font.color | The color to use for the font. Legal values are r,g,b. | black |
| kaptcha.noise.impl | The noise producer. | com.google.code.kaptcha.impl.DefaultNoise |
| kaptcha.noise.color | The noise color. Legal values are r,g,b. | black |
| kaptcha.obscurificator.impl | The obscurificator implementation. | com.google.code.kaptcha.impl.WaterRipple |
| kaptcha.background.impl | The background implementation. | com.google.code.kaptcha.impl.DefaultBackground |
| kaptcha.background.clear.from | Starting background color. Legal values are r,g,b. | light grey |
| kaptcha.background.clear.to | Ending background color. Legal values are r,g,b. | white |
| kaptcha.word.impl | The word renderer implementation. | com.google.code.kaptcha.text.impl.DefaultWordRenderer |
| kaptcha.session.key | The value for the kaptcha is generated and is put into the HttpSession. This is the key value for that item in the session. | KAPTCHA_SESSION_KEY |
| kaptcha.session.date | The date the kaptcha is generated is put into the HttpSession. This is the key value for that item in the session. | KAPTCHA_SESSION_DATE
|
