make form field check case insensitive

[php_begins]

I am using a captcha like image verification for my form fields.

I want to make my check case insensitive:

For example,

if the security word is 1A3e then 1a3e or 1a3E should work.(Upper Case or lower case does not matter)

Here is the check I am doin so far to see if my security word matches.

 

if(md5($_POST['security_word']).'a4xn' == $_COOKIE['tntcon'])

[xyph]

Use strtolower or strtoupper before calling the md5's.

 

Force both to be either all upper or all lowercase.

[php_begins]

i already tried that..but it didnt work:

 

if(strtolower(md5($_POST['security_word'])).'a4xn' == strtolower($_COOKIE['tntcon']))

[php_begins]

if(strtolower(md5($_POST['security_word']).'a4xn') == strtolower($_COOKIE['tntcon'])) does not work either..

[php_begins]

could it be because there are numbers in that image too?

[dzelenika]

md5(strtolower($_POST['security_word'])).'a4xn'

 

or

 

md5(strtolower($_POST['security_word']).'a4xn')

[php_begins]

nope..that doesnt work either...

[php_begins]

the only reason i could think of is it is an md5 behaviour issue..

[xyph]

I said before you call the MD5, you have to make the strings the same case.

 

Just use ReCaptcha. It's probably better than the system you have in place.

[Psycho]

You will ONLY be able to do this if the value in the cookie ($_COOKIE['tntcon']) was set to lower or upper case before BEFORE creating the MD5() value. You MUST get the user input in the exact same case as was used to create the validation value.

 

So, you will need to update the code that sets the cookie value AND update the code to check the POST value against the cookie value. Since you need to do the same thing in two different places you should create a function so you are guaranteed to be doing the exact same thing in both instances.

 

function createChecksum($code, $salt)
{
    return md5(strtolower(trim($code)).$salt);
}

 

Creating the value to store in the cookie

$tntcon = createChecksum($captchaCode, 'a4xn');
setcookie("tntcon", $tntcon, time()+300); //5 minutes

 

Verify user input

if(createChecksum($_POST['security_word'], 'a4xn') == $_COOKIE['tntcon'])