Captcha Alternative – Simple Math Question

captchasCaptchas have a huge usability problem. When generated too difficult (blurry letters, grainy background), user can’t get it right. When generated too easy (with sharp letters and white background), spam-bots will be able to read it. So, you have to decide which one to forgo; your readers or the spam. Or you can chose to stay in the middle and deal everyday with considerable amount of spam.

Any Alternative to Captchas?

Sure, one of the effective and more usable alternative is to ask simple questions that anyone can answer, except for spam-bots. These are either simple arithmetic questions or something that is common sense, here are some examples:

  • 2 + 4 = ? (answer 6)
  • six plus three is = ? (answer 9)
  • when you boil the water, it becomes cold or hot? (answer hot)
  • last name of the current president of US? (answer bush) etc.

These kind of plugins usually come in two forms; 1. you provide the question and the answer yourself and 2. you provide the numbers (eg. 1 – 10) and the plugin will generate random addition (subtraction, multiplication, division etc) of two numbers each time a page loads (eg. 2 + 8 = ?).

Most plugins are not compatible with WP 2.3.3

I have been searching for such a plugin that is compatible with WP 2.3.3. Most of the plugins I came across were, either out of date – not updated anymore, or, compatible with only WP 2.1 or 2.2 and not with the latest WP version – 2.3.3.

Some of you might had difficulty in commenting in my blog for the past few days. That’s because, one such plugin that I installed was not functioning properly. All the questions even answered correctly apparently didn’t pass the authorization. Thanks to Bhumika and Eddie Poh for pointing out the problem. Also, sorry for the inconvenience for anyone who couldn’t comment due to this issue.

WP Plugin, Math Comment Spam Protection

Fortunately, I found a plugin called Math Comment Spam Protection, which is compatible with WP 2.3.3. It’s a plugin that allows you to put simple arithmetic question for the commenters. As I said above, it’s a no issue for a human being but almost impossible task for a spam-bot to answer. (custom question based plugins are even better).

spam protectionAfter putting this plugin, number of spam comments decreased tremendously. In fact, so far, for the last 12 hours I have only received spam-trackbacks but not spam-comments.

Yesterday, the situation was different. With only Akismet installed, my blog was getting more than 300 spam comments. But so far so good, and I will probably stick to this plugin until I find a better one. For me, better plugin would be, something that allows you to input your own question and answer, not necessarily math question. Anyone knows such plugin that is compatible with WP 2.3.3? If you know, let me know. Thanks in advance.

Plugin page: http://sw-guide.de/wordpress/plugins/math-comment-spam-protection/



33 Comments on "Captcha Alternative – Simple Math Question"

  1. Recliners says:

    I find captchas quite irritating too. It is better when you use a simple math or logic question, the way you do.

  2. Jayson says:

    So I’m not the only one that has a hard time reading the captchas? I can’t express how annoying it is to constantly try and guess what letters they’re showing.

    We use the same math plugin for some of our blogs and it does work well. I see some people using questions and I think they have the latest WordPress available but I’m not sure where you can get these plugins. I’ll ask a few of them and see what I can come up with.

  3. Lori says:

    I’m am fixing to try this out. I’ve been searching forever for one so I’m glad to see you made if easy for me!

  4. Lori says:

    My captcha info is below the box and I would like it above the box. Can you tell me how you did that?

  5. Tom Beaton says:

    No kidding with the captchas – there are some that are ridiculously challenging. A right pain and can put you off a site altogether.

    Still better a captcha than having to log into a site to leave a comment. That is very impractical for people who follow many blogs.

  6. Jayson says:

    Hopefully this works out for you. I’m going to check it our for our blog right now

    http://blue-anvil.com/archives/wordpress-comment-spam-stopper-plugin

  7. Rice Blogger says:

    i guess you had more spam as you have more visitor as well….

    personally i do not like them…but if it is simple maths…not a problem….

  8. I hate captchas too, especially when I can’t read them. I’ve lost long comments because I’ve gotten the captcha wrong.

  9. I do prefer the simple maths questions but how long before the bots start to pick up on these too?

  10. Thank God, you have got the right handle on Captchas. What you have got here now, is great.

  11. Sergio says:

    this is an easy system for identify spammers and persons, but i prefeer work only with spam karma, is quick and easy to my people response and post with a easy system, dont you?

  12. Ades says:

    Sergio, I used SK too, it’s a good plugin. But I was looking for something simple yet effective, so this plugin fit the bill so to speak.

  13. Ades says:

    Lori, you need to put:

    above this code:

    <input type="text" name="mcspvalue" id="mcspvalue" value="" size="22" tabindex="4" />

    By default, it’s the opposite. The code is located in your comments.php

  14. billie says:

    capthas are the best solution for the pams

  15. Stefanie says:

    I definitely prefer the math or logic questions, but I never really thought they’d work. I guess I just figured that the spammers would eventually figure out the answers and be able to work around them.

  16. Futon-Matt says:

    I like the simple math on comments as well, it should eliminate tons of spammy crap.

  17. seo says:

    Why not have images and you can say whats on the picture? For example a picture of an apple where you have to pick apple from a drop down list of options or something.

  18. Ades says:

    seo, that’s a great idea too! as long as the pictures are not abstract ;)

  19. Hey Ades, this is really a good option to avoid captcha image. sometimes it is so unclear that we can’t really read it properly.
    Thanks for sharing it.

  20. shawal says:

    This kind of plugins are so important and very useful in protecting our self from the time to check all the spam comment… But, this plugins are only compatible with wordpress 2.3, is there any spam comment plugins that compatible with wordpress 2.5 ….

    Thanks in advance…..

  21. Ades says:

    shawal, have you installed it on wp2.5? if not you may want to try it, some plugins work fine with wp2.5

  22. Roger says:

    Why not avoid a plug in for this all together. Instead place a question (using ) and also an input field, and I’m sure thiere is some php way or probably even simpler way to comapare the input to the answer you’re using and if they’re not the same don’t have the process continue, don’t have it do anything.

  23. I prefer this method over Captchas due to my poor eyesight, this makes it far easier for me to comment on blogs, submit to directories, or any other task where automation has ruined it. I also like the “fire is: ?” or “bananas are the color: ?” types of questions as well.

  24. The problem with the current math logic problems is that many of the commercial spamming software products can read captcha let alone simple math problems.

  25. Cocacolya says:

    sometimes it’s hard enough..to calculate..3-4=-1…awful

  26. benja says:

    good ones. Even though there are still sites with the other ones I really like this one

  27. Quite simple captchas are much better than complicated captcha.
    I always prepare captcha like this “when you boil the water, it becomes cold or hot? (answer hot)”
    No crack or software can brake such captcha. This is very simple and logical

  28. tplst says:

    U right Captchas have many problem. Many users cant get it right. But many spammers pass this protect :s i cant avert this with Captchas.i like math questions. its very easy and and safe ( my opinion )

  29. nice plugin, but is it compatible with wp 2.9.1?

  30. I hate captchas! Sometimes they are difficult to read and hassle when commenting.

  31. fern says:

    I have heard for captcha’s being defeated but I have yet to hear of math problems having the same issues

  32. This is great! You should apply these on your blog, as they are easy to use for you and your readers (although there will still be people who wouldn’t like it). I am one of those people who hate deciphering those impossible looking captchas with the lines all over the letters making it almost unreadable.

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