My Captcha, Opinions wanted...

brendan2b

Hello,

I am working on a website that users will come to in order to register for services. Their user name is their email address.

I have them validating their email by clicking on an activation link in an email sent to them but I want to also include a captcha as well to verify if they are truly a human.

I have developed my own captcha using the image functions and I am just curious as to which on my ideas may be the best or if none are any good.

1) Display a box with a crazy background but 9 random letters/numbers that the user has to type in.

2) Having an image where the user needs to click on a certain dot in the image in order to verify that they are a human

3) Displaying an image with a crazy background that will have any of the following in it:

4 plus 6
four plus six
four plus 6
6 minus 2
6 minus two
two plus 3
five times seven
five times 2

Where the user must give the correct answer.

The first is the least effective, the second I am not sure if I can do with my knowledge, and the last one seems to be pretty secure as well and feasible with my skillset.

Of course I will be changing the fonts and colors of the lines/text in the images randomly as well.

I know these can be cracked with a large group of talented/smart people, even just one very smart person, but I want to know the best way to avoid that.

Any feedback on how I should approach this would be most appreciated.
If you think im an idiot and all these ideas are garbage then that's fine too. Better to find out sooner than later : ].

Thanks again,

Brendan

mahipm

9 letters might be too much with a Crazy BG, people might get annoyed.. 4-5 should be fine..
You could use different fonts, as well if u like!

2nd idea isn't common, so user will have hard time doing that to submit a form. (i believe)

3rd might be cool tho. (and user only has to type one number, so easy for them as well)

Might want to google: free php captcha
There're tons of free php scripts for those... so just try something hah

NogDog

Be sure to consider the impact of any graphical scheme on visually impaired users. While I am far from being legally blind, my eyes are not real good to begin with, and on top of that I had a torn retina in one eye last year, with the resulting damage still affecting my sight. I find many captcha images very difficult to read and only continue with them if I really want to proceed.