How to Validate a Credit Card in PHP

What is the best way to validate a credit card in PHP?

There are three parts to the validation of the card number:

1. PATTERN - does it match an issuers pattern (e.g. VISA/Mastercard/etc.)
2. CHECKSUM - does it actually check-sum (e.g. not just 13 random numbers after "34" to make it an AMEX card number)
3. REALLY EXISTS - does it actually have an associated account (you are unlikely to get this without a merchant account)

Pattern

• MASTERCARD Prefix=51-55, Length=16 (Mod10 checksummed)
• VISA Prefix=4, Length=13 or 16 (Mod10)
• AMEX Prefix=34 or 37, Length=15 (Mod10)
• Diners Club/Carte Prefix=300-305, 36 or 38, Length=14 (Mod10)
• Discover Prefix=6011,622126-622925,644-649,65, Length=16, (Mod10)
• etc. (detailed list of prefixes)

Checksum

Most cards use the Luhn algorithm for checksums:

Luhn Algorithm described on Wikipedia

There are links to many implementations on the Wikipedia link, including PHP:

<?
/* Luhn algorithm number checker - (c) 2005-2008 shaman - www.planzero.org *
 * This code has been released into the public domain, however please      *
 * give credit to the original author where possible.                      */

function luhn_check($number) {

  // Strip any non-digits (useful for credit card numbers with spaces and hyphens)
  $number=preg_replace('/\D/', '', $number);

  // Set the string length and parity
  $number_length=strlen($number);
  $parity=$number_length % 2;

  // Loop through each digit and do the maths
  $total=0;
  for ($i=0; $i<$number_length; $i++) {
    $digit=$number[$i];
    // Multiply alternate digits by two
    if ($i % 2 == $parity) {
      $digit*=2;
      // If the sum is two digits, add them together (in effect)
      if ($digit > 9) {
        $digit-=9;
      }
    }
    // Total up the digits
    $total+=$digit;
  }

  // If the total mod 10 equals 0, the number is valid
  return ($total % 10 == 0) ? TRUE : FALSE;

}
?>

I need to validate credit-card details

Magento comes with Really Easy Field Validation in place so you only need to add some classes to the fields in question.

• validate-cc-type or validate-cc-type-select
• validate-cc-number
• validate-cc-cvn
• validate-cc-exp

However the normal payment modules should already be using these so what are you doing that breaks it or otherwise needs CC details?

What is the best way to validate a credit card in codeigniter

As people already told you, CodeIgniter is a php framework, coded using php, works in a php environment and makes use of..,php classes and functions :).

What's more, the file you linked to is a simple function. One function. You know what you can do? Take the file as it is, name it creditcard_helper.php, put it inside the helpers folder, open it and place the whole code inside this snippet (ugly but necessary, as whenever you'll load the helper a second time it would give you error otherwise):

if(!function_exists('checkCreditCard')
{
   //the whole content goes here untouched;
}

And you're set. Just use:

$this->load->helper('creditcard');
if(checkCreditCard($cardnumber, $cardname, &$errornumber, &$errortext))
{
  echo 'card OK';
}
else
{
 echo 'wrong card type/number';
}

how to validate credit card number and Card Code Verification (ccv)

Right, so after some initial fail on understanding what was being asked for, I think the following should help.

http://community.developer.authorize.net/t5/The-Authorize-Net-Developer-Blog/Validating-Credit-Card-Information-Part-3-of-3-CVV-Numbers/ba-p/7657

The post provides some code that validates a CVV number. It obviously can't tell you if it's correct or not though.

Hopefully that helps.

Credit Card Validation using PHP

You want to look at the Luhn algorithm: http://en.wikipedia.org/wiki/Luhn_algorithm

This is the algorithm that basically looks at a credit card number and decides if it's a valid number. This doesn't mean that it's an actual, real credit card. You would need a credit card processor/gateway for that (see: Authorize.NET, Paypal, etc).

This algorithm has been implemented in PHP many times, and I'm sure with a simple Google search you can find some code in PHP that representes the Luhn algorithm.

Good luck.

Validating credit card details in Codeigniter

In CodeIgniter, you can add custom validators. Symfony2 offers a bunch of validators (including credit card details) and you can just use those classes in CI.

For example, the 'card scheme' validator - documentation and code.

how to validate credit card info(billing, card number etc) through authorize.net?

No. The only way to know a credit card is valid is to process a transaction. Only then is the bank contacted to validate the credit card.

FYI, I am the author of the article you linked to.

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