Better way
Every Captcha the use can be cracked by some software. But, a captcha isn´t just a random alpha numeric code with fanzy colors and everything. You can use captchas in different ways/arts/etc. For example: the captcha i programmed get a question from the database and "ask" the user this question, i.e. "What color has the sky?" the answer whould be "blue". The String is converted to a lower string und if a space is at the end or start, i cut it of.
The only thing is, there is a limit of questions you can ask, and if the are recorded by the spammers, they can made a simple question/answer function in the bot.
We have the idea to use pictures or create pictures with GD or Imagemagic and ask for the main color, to crack this, you have to learn your bot the color and what hexcode it could be. On the other hand, you have to programm it to your software first.
The idea with a picture could be extremly heavy. If the picture shows a elephant, you can ask "What Animal is on the Picture?" and to prevent that the bot recognize the picture with a hash, you can throw random pixel errors on the picture, that would be the best thing. Humans can see what the picture shows without getting eyecancer of ugly warped text you have to decrypt. In that case, you only need a handfull of pictures, questions and answers, easy for everyone, execpt the one who programm it ;) But if its programmed, it could be the best captcha on earth.
And no, i dont like the book captcha, its stupid and could be cracked.
Any ideas of other captchas, feel free to mail me @ spelter<dot>hof[@]freenet<dot>de (what for the @ in brackets)
Biting the hand that feeds IT
