NAME

CheckDigits::M10_001 - compute check digits for Bahncard (DE), IMEI, IMEISV, ISIN, Miles&More, Payback (DE), Personnummer (SE), Passport (BR), Credit Cards, SSN (US), Samordningsnummer (SE), VAT RN (ES), VAT RN (IT), VAT RN (SE), International Securities Identifikation Number (ISIN), CUSIP

SYNOPSIS

  use Algorithm::CheckDigits;
  $visa = CheckDigits('visa');
  if ($visa->is_valid('4111 1111 1111 1111')) {
        # do something
  }
  $cn = $visa->complete('4111 1111 1111 111');
  # $cn = '4111 1111 1111 1111'
  $cd = $visa->checkdigit('4111 1111 1111 1111');
  # $cd = '7'
  $bn = $visa->basenumber('4111 1111 1111 1111');
  # $bn = '4111 1111 1111 111'

DESCRIPTION

ALGORITHM

1.: Beginning right all numbers are weighted alternatively 1 and 2 (that is the check digit is weighted 1).
2.: The total of the digits of all products is computed.
3.: The sum of step 3 ist taken modulo 10.
4.: The check digit is the difference between 10 and the number from step 3.

To validate the total of the digits of all numbers inclusive check digit taken modulo 10 must be 0.