Now Using Lyla Captcha

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Thanks to Peter Farrell for creating the free and open source Lyla Captcha ColdFusion component to help stop comment spam, and thanks to Brian Rinaldi for instructions and code appropriate for usage in BlogCFC.

Comments now require the guest to type the text rendered in the image into a text field for validation. Soon I will add this to the Contact Me page as well.

To simplify the task for the guest, I create an array of known strings such as company names, well known terms, or other recognizable words, then select one random array item to be passed to the createCaptchaHashReference(String s) method. Yes, this partially weakens Captcha, but I think it should still be very effective.

posted on 3 May, 2006 at 6:20 PM.
ColdFusion, Blogging | Comments (5)

Comments

Glad I could be of help. Looks like it is working well :)

comment by Brian Rinaldi, posted at 5/3/06 6:50 PM

Probably not related, but if you submit a form without the captcha (or wrong captcha), it posts to itslef and bug out with your name ... I entered name, email, and url ... and it seems like there's a problem with quotes perhaps ...

comment by Rob Gonda, posted at 5/3/06 6:59 PM

Rob, thanks for the heads up. That was an unrelated bug caused by how I implemented the Web Site comment field, a feature that was not in the BlogCFC 4.0 Beta 1 version I'm using.

comment by Steven Erat, posted at 5/3/06 7:39 PM

I kinda like that idea. sometimes the difference between O and 0 or 8 or B etc. can be frustrating. at least this way you can use your Human Context Analysis Engine to resolve any ambiguity

comment by Michael White, posted at 5/4/06 10:06 AM

Glad that like the project Steven! Yeah, you are right that the array of possible texts reduces the effectiveness - however, on low traffic sites (I know we've discussed your trafic in the past ;-) this should be fine. You might have to expand your exemplar set in the future to fight off some spammers.

Michael, you're right the difference between 0/O, 8/B or l/I (that's L and i) can be frustrating. By design however, most captchas include those characters to confuse OCR software and other techniques. By definition, supposedly "good" captchas are usually only 85-90% solvable -- the rest of the times bring in that ambiguity you speak of. But, in the end -- you can control what goes into the Lyla and I'll be implementing a method to create your own set for random character generation.

comment by Peter J. Farrell, posted at 5/8/06 1:01 AM

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I live west of Boston and work as a Software Engineer with ColdFusion and Flex, specializing in Linux. Recently I graduated in Professional Digital Photography from CDIA.