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Toby Inkster

NAME

Crypt::XkcdPassword - see http://xkcd.com/936/

SYNOPSIS

 use 5.010;
 use Crypt::XkcdPassword;
 
 say Crypt::XkcdPassword->make_password;

DESCRIPTION

Yet another password generator module inspired by http://xkcd.com/936/.

Constructor

  • new(%attr)

    Creates a new generator. A single generator can be used to generate as many passwords as you like.

Attributes

This is a Moo-based class.

  • words

    An object consuming the Crypt::XkcdPassword::Words role.

    Can be coerced from a short string. This will be prepended with Crypt::XkcdPassword::Words:: to form a class name, and the new constructor will be called.

    Can also coerce from an arrayref where the first item in the array is a short string used as above, and the other items in the array are passed to the constructor.

    The default is "EN", which means the class used as a source for words is Crypt::XkcdPassword::Words::EN.

  • rng

    A coderef for generating a random number. The coderef is called and passed a single numeric argument. The coderef is expected to generate a random, positive integer, smaller than the argument. The default is:

     sub { int(rand($_[0])) }

    Perl's default random number generator is often though insufficient for practical cryptography, so you may wish to use another random number generator.

Methods

  • make_password($size, $filter)

    Returns the password as a string.

    $size is the length of the password in words. It defaults to 4. For the English dictionary that provides over 47 bits of entropy; for the Italian dictionary (which has twice as many words), about 56 bits of entropy.

    $filter is a test against which each word is checked. It can be a sub returning true if the word is OK, or a regular expression matching OK words. Words which are not OK will be excluded from passwords. The default is to allow any words found in the provided dictionary.

    For reference, 47 bits of entropy is roughly equivalent to an eight digit random case-sensitive alphanumeric password (i.e. 62^8).

    This can be called as an object method, or (if you have no desire to change the defaults for the rng and words attributes) as a class method. That is, the first line of the example below is a shortcut for the second line:

     say Crypt::XkcdPassword->make_password($size);
     say Crypt::XkcdPassword->new->make_password($size);

    Note that the passphrases returned may not be ASCII-safe, and may sometimes be inappropriate for uttering in polite company. See Crypt::XkcdPassword::Examples for ways of using $filter to resolve this situation.

  • chars

    No-op, provided for compatibility with Data::SimplePassword.

  • provider

    No-op, provided for compatibility with Data::SimplePassword.

Bundled Word Lists

Crypt::XkcdPassword::Words::EN is a list of 10,000 common English words.

Crypt::XkcdPassword::Words::EN::Roget is a list of about 8500 words. The words are less questionable, but as there are fewer of them, pass phrases will be chosen from a smaller pool, thus slightly more guessable.

Crypt::XkcdPassword::Words::IT is a list of 20,000 common Italian words.

Crypt::XkcdPassword::Words::sys uses your system's word list (/usr/share/dict/words by default). The constructor can be passed an alternative filename.

BUGS

Please report any bugs to http://rt.cpan.org/Dist/Display.html?Queue=Crypt-XkcdPassword.

SEE ALSO

Crypt::XkcdPassword::Examples - how to do stuff with this module.

Data::SimplePassword - I borrowed this module's interface, so it should mostly be possible to s/Data::SimplePassword/Crypt::XkcdPassword/.

Crypt::PW44 - similar to this one, but with a smaller list of words.

http://xkcd.com/936/.

AUTHOR

Toby Inkster <tobyink@cpan.org>.

COPYRIGHT AND LICENCE

This software is copyright (c) 2012, 2014 by Toby Inkster.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.

DISCLAIMER OF WARRANTIES

THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.