FYI -- http://latimesblogs.latimes.com/technology/2011/03/web-security-against-hack... Technology The best Web security against hackers and spammers: advanced math! March 4, 2011 | 9:41 am If you don't want spam-bots or bad guys breaking into your site, make them do calculus. That's the approach the folks at a Croatia's Ru?er BoÂkovic' Institute are taking. Before you can log in to the research institute's Quantum Random Bit Generator service, you have to enter your name, password and affiliated organization, and then solve a math problem that would make most people run for the hills: http://www.irb.hr/en/geninfo/ http://random.irb.hr/signup.php [see article] [Captcha with calculus problem] The challenge is an extra-hard version of a regular CAPTCHA-type question (see image here), where users are prompted to retype a set of letters from a blurry image. And, like CAPTCHAs, users are given clemency if they can't get the first one right. "If you don't know the answer to this question," it says, "reload the page and you'll (probably) get another, easier question." How kind of you. It seems these scientists want to ward off ruffians who can't do advanced math. After all, the service they're offering is access to truly random numbers -- a difficult computer science feat on its own, and one that only responsible adults should have access to. But these math elitists may have a problem on their hands. As calculus teachers around the world are now discovering, the Internet will now do your math homework for you. Just go to WolframAlpha and pop in the problem, and boom, you'll have access to all the random numbers your heart could desire: http://www.wolframalpha.com/input/?i=d%2Fdx%28sin%282x+-+pi%2F2%29+%2B+6%29%... Ha, ha, how do you like your little trick now, eggheads! Everyone knows the derivative of the sin of 2X minus pi over two plus six where x = 2 pi is zero! Isn't it? -- David Sarno