1 package Business::CreditCard;
3 # Business::CreditCard.pm
5 # Jon Orwant, <orwant@media.mit.edu>
8 # 17 Jan 97 - 0.21 released.
9 # short numbers and numbers with letters are no longer kosher.
10 # 1 Feb 2001 - 0.22 released, new maintainer, MakeMaker installation
12 # Copyright 1995,1996,1997 Jon Orwant. All rights reserved.
13 # This program is free software; you can redistribute it and/or
14 # modify it under the same terms as Perl itself.
16 # Version 0.22. Module list status is "Rdpf."
21 use vars qw( @ISA $VERSION );
23 @ISA = qw( Exporter );
29 C<Business::CreditCard> - Validate/generate credit card checksums/names
33 use Business::CreditCard;
35 print validate("5276 4400 6542 1319");
36 print cardtype("5276 4400 6542 1319");
37 print generate_last_digit("5276 4400 6542 131");
39 Business::CreditCard is available at a CPAN site near you.
43 These subroutines tell you whether a credit card number is
44 self-consistent -- whether the last digit of the number is a valid
45 checksum for the preceding digits.
47 The validate() subroutine returns 1 if the card number provided passes
48 the checksum test, and 0 otherwise.
50 The cardtype() subroutine returns a string containing the type of
51 card: "MasterCard", "VISA", and so on. My list is not complete;
54 The generate_last_digit() subroutine computes and returns the last
55 digit of the card given the preceding digits. With a 16-digit card,
56 you provide the first 15 digits; the subroutine returns the sixteenth.
58 This module does I<not> tell you whether the number is on an actual
59 card, only whether it might conceivably be on a real card. To verify
60 whether a card is real, or whether it's been stolen, or what its
61 balance is, you need a Merchant ID, which gives you access to credit
62 card databases. The Perl Journal (http://tpj.com/tpj) has
63 a Merchant ID so that I can accept MasterCard and VISA payments; it
64 comes with the little pushbutton/slide-your-card-through device you've
65 seen in restaurants and stores. That device calculates the checksum
66 for you, so I don't actually use this module.
68 These subroutines will also work if you provide the arguments
69 as numbers instead of strings, e.g. C<validate(5276440065421319)>.
75 The Perl Journal and MIT Media Lab
79 Current maintainer is Ivan Kohler <ivan-business-creditcard@420.am>.
80 Please don't bother Jon with emails about this module.
84 @EXPORT = qw(cardtype validate generate_last_digit);
89 return "Not a credit card" if $number =~ /[^\d\s]/;
93 return "Not a credit card" unless length($number) >= 13 && 0+$number;
95 return "VISA card" if substr($number,0,1) == "4";
96 return "MasterCard" if substr($number,0,1) == "5";
97 return "Discover card" if substr($number,0,1) == "6";
98 return "American Express card" if substr($number,0,2) == "37";
99 return "Diner's Club, Transmedia, or other dining/entertainment card" if substr($number,0,1) == "3";
103 sub generate_last_digit {
105 my ($i, $sum, $weight);
109 for ($i = 0; $i < length($number); $i++) {
110 $weight = substr($number, -1 * ($i + 1), 1) * (2 - ($i % 2));
111 $sum += (($weight < 10) ? $weight : ($weight - 9));
114 return (10 - $sum % 10) % 10;
119 my ($i, $sum, $weight);
121 return 0 if $number =~ /[^\d\s]/;
125 return 0 unless length($number) >= 13 && 0+$number;
127 for ($i = 0; $i < length($number) - 1; $i++) {
128 $weight = substr($number, -1 * ($i + 2), 1) * (2 - ($i % 2));
129 $sum += (($weight < 10) ? $weight : ($weight - 9));
132 return 1 if substr($number, -1) == (10 - $sum % 10) % 10;