Another Captcha alternative

While not quite publicly available, I ran across this on a site the other day and found it interesting.

http://dice-captcha.com/

The only problem is (at least for me) that the developer says he wants to encrypt his PHP back-end with Zend Encoder and/or IonCube. We've been communicating via email, and here's his last response:

I understand your concerns and will consider possibly options. Do you have any suggestions?

Does anybody have any ideas? I was thinking maybe encrypt the free version (as well as the branding) but have the paid version unencrypted as well as unbranded. I had intended to buy an unbranded version, and would even pay a little more to get it unencrypted as well.

Have you looked at this far-less-slick-but-open-source equivalent? https://github.com/and/dice_captcha