---
name: "Algorithm::CheckDigits::MXX_001"
section: "3pm"
platform: "linux"
package: "libalgorithm-checkdigits-perl"
version: "1.3.6-2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/Algorithm::CheckDigits::MXX_001"
---

# Algorithm::CheckDigits::MXX\_001(3pm)

compute check digits for german Personalausweis (pa\_de) or ABA routing numbers (aba\_rn)

## NAME

CheckDigits::MXX\_001 - compute check digits for german Personalausweis (pa\_de) or ABA routing numbers (aba\_rn)

## SYNOPSIS

```
  use Algorithm::CheckDigits;
  $pa = CheckDigits('pa_de');
  if ($pa->is_valid('2406055684D<<6810203<0705109<6')) {
        # do something
  }
  if ($pa->is_valid('2406055684') {
        # do_something
  }
  $cn = $pa->complete('240605568_D<<681020_<070510_<_');
  # $cn = '2406055684D<<6810203<0705109<6'
  $cd = $pa->checkdigit('2406055684D<<6810203<0705109<6');
  # $cd = '6'
  $bn = $pa->basenumber('2406055684D<<6810203<0705109<6');
  # $bn = '240605568_D<<681020_<070510_<_'
  $aba = CheckDigits('aba_rn');
  if ($aba->is_valid('789456124')) {
       # do something
  }
```

## DESCRIPTION

### ALGORITHM

- 1\.

  Beginning left all digits are weighted with 7,3,1,7,3,1,... for *pa\_de* or 3,7,1,3,7,1,3,7,1 for *aba\_rn*.

- 2\.

  The sum of those products is computed.

- 3\.

  For *pa\_de* the checksum is the last digit of the sum from step 2 (modulo 10).

  For *aba\_rn* the checksum is the difference of the sum from step 2 to the next multiple of 10.

- 4\.

  For the german Personalausweis step 1 to 3 is performed for every part of the number and for all 3 parts including the particular checkdigit to compute the total checksum.

  If the number solely consists of digits, the checksum is just computed once according to algorithm given above.

### METHODS

- is\_valid($number)

  Returns true only if `$number` consists solely of numbers and the last digit is a valid check digit according to the algorithm given above.

  Returns false otherwise,

- complete($number)

  The check digit for `$number` is computed and concatenated to the end of `$number`.

  Returns the complete number with check digit or '' if `$number` does not consist solely of digits and spaces.

- basenumber($number)

  Returns the basenumber of `$number` if `$number` has a valid check digit.

  Return '' otherwise.

- checkdigit($number)

  Returns the checkdigit of `$number` if `$number` has a valid check digit.

  Return '' otherwise.

### EXPORT

None by default.

## AUTHOR

Mathias Weidner, `"<mamawe@cpan.org>"`

## THANKS

Aaron W. West pointed me to a fault in the computing of the check digit. Jim Hickstein made me aware of the ABA routing numbers.

## SEE ALSO

perl, CheckDigits, *www.pruefziffernberechnung.de*, *http://answers.google.com/answers/threadview/id/43619.html*, *http://www.brainjar.com/js/validation/*