You could always modify it into your own block and incorporate ReCaptcha. It wouldn't be that hard.

Job.

How do I do that?

Unless you're familiar with PHP you'll struggle.

The CAPTCHA used on concrete5.org (among probably millions of other sites) is called reCAPTCHA.

From reCAPTCHA website:

"reCAPTCHA is a free CAPTCHA service that helps to digitize books, newspapers and old time radio shows..."

"...reCAPTCHA improves the process of digitizing books by sending words that cannot be read by computers to the Web in the form of CAPTCHAs for humans to decipher. More specifically, each word that cannot be read correctly by OCR is placed on an image and used as a CAPTCHA. This is possible because most OCR programs alert you when a word cannot be read correctly.

But if a computer can't read such a CAPTCHA, how does the system know the correct answer to the puzzle? Here's how: Each new word that cannot be read correctly by OCR is given to a user in conjunction with another word for which the answer is already known. The user is then asked to read both words. If they solve the one for which the answer is known, the system assumes their answer is correct for the new one. The system then gives the new image to a number of other people to determine, with higher confidence, whether the original answer was correct..."


The fact the words might sometimes be smudges is because they are scanned from poor prints and reCAPTCHA needs your help to read it. If you have problem reading a word, then just hit the reload icon and you will be presented with another.

I was repeatedly redoing it, and each time, the computer claimed I never got it right. One word was clear to read, and the other word was so smeared that I had to make something up about what the letters might be.

So, I was never able to submit my form. Everything works out for the best.