Credit Card Checking

Dillenger

Hi,

I don't want to process credit card info, I'm only interested in checking if the number or expiry dates are valid... does anyone have the code to do this?

Thanks

shu

It depends on who your payment gateway is! As different gateways might return different reponse codes to your queries! You can implement a whole credit card payment thingy with curl. It should be pretty easy!

Ooops... I misread your question! I thought you wanted to check the date against your credit card merchant.

DigitalExpl0it

what id do is.

in the texbox form for the credit card number

Id count how many chr the user puts in. And also check to see if they are adding spaces if so then you will need two checks for that.

for the exp date, id just do a match

if ($selectdat < $todaysdate) {
//wrong date
} else {
//correct date
}

ednark

here is the algorithm for checking if a card number is valid

1) must be an integer

2) must be between 13 and 16 digits long

3) if not 16 digits pad left with 0's

4) reverse the string

5) the only hard part :

from left add up all odd spaced digits, from left add up all even spaced digits and multiply them by two and add each digit together- add the results... this can be represented with this multiply mask :

1212121212121212

this means if you have the card number '0000000000000089'

you reverse it to get '9800000000000000'

then apply the multiply mask:

9 x 1 = 9
8 x 2 = 16 so 1 + 6 = 7

9 + 7 = 16

so after the first two digits your running total is 16

6) if the total is evenly devisible by 10 ( $total%10==0 ) then the credit card number is valid

16%10=6 so invalid

7) each type of card Visa, Diners, etc... ontop of this has a range of valid numbes... for instance visa must be 14-16 digits long and start with a 4

mastercard must be 16 digits and start with either 51 or 55

i don't know where a comprehensive list of these things are for each credit card... those are just the ones i know off the top of my head

go ahead and see if you can come up with an algorithm to do what i explained ...

acidbox

There are some functions on zend that has a formula to validate credit cards. I don't know if it useful but perhaps it would work.

http://www.zend.com/codex.php?id=31&single=1

coditoergosum

I wrote a script a while ago that does exactly what ednark just explained. It is located here: http://www.gagon.net/?wip=1&project=phpccvalidate. The script tests the number on 3 things, it first must have the correct first number(s), then it checks the length of the number, then runs a mod 10 algorithm on the number.

It currently only works with Visa and Mastercard though.

There is a link to the source on the same page. The code is pretty sloppy, and not commented extremely well right now though.

I don't care if you use my code... as long as you tell me you're doing so.

juschillinnow

hey ednark, I'm not real advanced with math so this question is simply for my learning and not criticize....

Can you explain in a little more detail about the alogarithm thing....

Maybe give me a complete working example and explain why you're doing what it is that you're doing....

If you have the time!

MrRosary

After spending some time trying to sort out credit card and on line purchasing the company I work for signed up to World Pay

They handle all the credit card stuff including dealing with banks and refunds for returned goods. It costs a little and takes a while to set up with your bank etc but its worth it.

A /lot/ easier.......

MrRosary