NAME

Crypt::PerfectPaperPasswords - Steve Gibson' Perfect Paper Passwords

VERSION

This document describes Crypt::PerfectPaperPasswords version 0.02

SYNOPSIS

use Crypt::PerfectPaperPasswords;

my $pass_phrase  = 'Fromage';
my $ppp          = Crypt::PerfectPaperPasswords->new;
my $sequence_key = $ppp->sequence_from_key( $pass_phrase );
my $first        = 1;
my $count        = 100;
my @passcodes    = $ppp->passcodes( $first, $count, $sequence_key );

DESCRIPTION

From https://www.grc.com/ppp.htm

GRC's "Perfect Paper Passwords" (PPP) system is a straightforward,
simple and secure implementation of a paper-based One Time Password
(OTP) system. When used in conjunction with an account name &
password, the individual "passcodes" contained on PPP's "passcards"
serve as the second factor ("something you have") of a secure multi-
factor authentication system.

This is a Perl implementation of the PPP passcode generator.

INTERFACE

new

Create a new Create::PerfectPaperPasswords instance. Options may be passed:

my $ppp = Crypt::PerfectPaperPasswords->new(
    alphabet => '0123456789abcdef',
    codelen  => 2
);

The following options are supported:

alphabet

The alphabet to use for encoding. Defaults to Steve Gibson's:

23456789!@#%+=:?abcdefghijkmnopq
rstuvwxyzABCDEFGHJKLMNPRSTUVWXYZ

The size of the alphabet need not be a power of two.

codelen

The number of raw bytes in each passcode. This setting isn't especially useful: it can't currently be set to more than 4 and setting it to less than 3 is pretty pointless. Defaults to 3.

alphabet

Get the alphabet used by this object.

my $alphabet = $ppp->alphabet;

codelen

Get the code length for this object.

my $codelen = $ppp->codelen;

sequence_from_key

Generate a sequence key from a passphrase.

my $seq_key = $ppp->sequence_from_key( 'Fromage' );

random_sequence

Generate a random sequence key.

my $seq_key = $ppp->random_sequence;

Relies on the output of random_data for its entropy.

random_data

Returns some random data. This is the entropy source for random_sequence. This implementation returns a string that is the concatenation of

• The real time (using the microsecond clock)

• The next seed value

• Address of $self

• Address of a newly allocated scalar

• Process ID

The seed value is the microsecond time when this object was created and is incremented by one each time it's used.

For a lot of uses this is probably an adequate entropy source - but I'm not a cryptographer. If you'd like better entropy consider subclassing and provding a random_data that reads from /dev/urandom.

passcodes

Get an array of passcodes.

my @passcodes = $ppp->passcodes(1, 70, $seq_key);

The first two arguments are the starting position (1 .. n) and the number of passcodes to generate. The starting position may be a large number - in which case it should be passed as a decimal string.

my @pc = $ppp->passcodes('9999999999999999999999', 100, $seq_key);

Returns an array of strings containing the generated passcodes.

CONFIGURATION AND ENVIRONMENT

Crypt::PerfectPaperPasswords requires no configuration files or environment variables.

DEPENDENCIES

Crypt::Rijndael

Digest::SHA256

Math::BigInt

Scalar::Util

Time::HiRes

INCOMPATIBILITIES

None reported.

BUGS AND LIMITATIONS

No bugs have been reported.

Please report any bugs or feature requests to bug-crypt-perfectpaperpasswords@rt.cpan.org, or through the web interface at http://rt.cpan.org.

AUTHOR

Andy Armstrong <andy@hexten.net>

Original Perfect Paper Passwords implementation by Steve Gibson. More details here:

L<http://www.grc.com/ppp.htm>

LICENCE AND COPYRIGHT

Copyright (c) 2007, Andy Armstrong <andy@hexten.net>.

This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself. See perlartistic.