NAME

       Authen::Passphrase::PHPass - passphrases using the phpass algorithm

SYNOPSIS

               use Authen::Passphrase::PHPass;

               $ppr = Authen::Passphrase::PHPass->new(
                       cost => 10, salt => "NaClNaCl",
                       hash_base64 => "ObRxTm/.EiiYN02xUeAQs/");

               $ppr = Authen::Passphrase::PHPass->new(
                       cost => 10, salt_random => 1,
                       passphrase => "passphrase");

               $ppr = Authen::Passphrase::PHPass->from_crypt(
                       '$P$8NaClNaClObRxTm/.EiiYN02xUeAQs/');

               $ppr = Authen::Passphrase::PHPass->from_rfc2307(
                       '{CRYPT}$P$8NaClNaClObRxTm/.EiiYN02xUeAQs/');

               $cost = $ppr->cost;
               $cost_base64 = $ppr->cost_base64;
               $cost = $ppr->nrounds_log2;
               $cost_base64 = $ppr->nrounds_log2_base64;
               $salt = $ppr->salt;
               $hash = $ppr->hash;
               $hash_base64 = $ppr->hash_base64;

               if($ppr->match($passphrase)) { ...

               $passwd = $ppr->as_crypt;
               $userPassword = $ppr->as_rfc2307;

DESCRIPTION

       An object of this class encapsulates a passphrase hashed using the phpass algorithm invented by Solar
       Designer and described at <http://www.openwall.com/phpass/>.  This is a subclass of Authen::Passphrase,
       and this document assumes that the reader is familiar with the documentation for that class.

       The phpass algorithm is based on the MD5 message digest algorithm.  There is an eight-byte salt, which is
       conventionally restricted to consist of base 64 digits.  There is also a cost parameter that controls the
       expense of hashing.  First the salt and passphrase are concatenated and hashed by MD5.  Then, 2^cost
       times, the hash from the previous stage is concatenated with the passphrase and hashed by MD5.  The
       passphrase hash is the output from the final iteration.

       The passphrase hash is represented in ASCII using the crypt format with prefix "$P$".  The first
       character after the format prefix is a base 64 digit giving the cost parameter.  The next eight
       characters are the salt.  The salt is followed by 22 base 64 digits giving the hash.  The base 64 digits
       are ".", "/", "0" to "9", "A" to "Z", "a" to "z" (in ASCII order).

CONSTRUCTORS

       Authen::Passphrase::PHPass->new(ATTR => VALUE, ...)
           Generates a new passphrase recogniser object using the phpass algorithm.  The following attributes
           may be given:

           cost
               Base-two logarithm of the number of hashing rounds to perform.

           cost_base64
               Base-two logarithm of the number of hashing rounds to perform, expressed as a single base 64
               digit.

           nrounds_log2
               Synonym for cost.

           nrounds_log2_base64
               Synonym for cost_base64.

           salt
               The salt, as an eight-byte string.

           salt_random
               Causes salt to be generated randomly.  The value given for this attribute is ignored.  The salt
               will be a string of eight base 64 digits.  The source of randomness may be controlled by the
               facility described in Data::Entropy.

           hash
               The hash, as a 16-byte string.

           hash_base64
               The hash, as a string of 22 base 64 digits.

           passphrase
               A passphrase that will be accepted.

           The cost and salt must be given, and either the hash or the passphrase.

       Authen::Passphrase::PHPass->from_crypt(PASSWD)
           Generates a new phpass passphrase recogniser object from a crypt string.  The crypt string must
           consist of "$P$", one base 64 character encoding the cost, the salt, then 22 base 64 digits giving
           the hash.  The salt must be exactly 8 characters long, and cannot contain any character that cannot
           appear in a crypt string.

       Authen::Passphrase::PHPass->from_rfc2307(USERPASSWORD)
           Generates a new phpass passphrase recogniser object from an RFC 2307 string.  The string must consist
           of "{CRYPT}" (case insensitive) followed by an acceptable crypt string.

METHODS

       $ppr->cost
           Returns the base-two logarithm of the number of hashing rounds that will be performed.

       $ppr->cost_base64
           Returns the base-two logarithm of the number of hashing rounds that will be performed, expressed as a
           single base 64 digit.

       $ppr->nrounds_log2
           Synonym for "cost".

       $ppr->nrounds_log2_base64
           Synonym for "cost_base64".

       $ppr->salt
           Returns the salt, as a string of eight bytes.

       $ppr->hash
           Returns the hash value, as a string of 16 bytes.

       $ppr->hash_base64
           Returns the hash value, as a string of 22 base 64 digits.

       $ppr->match(PASSPHRASE)
       $ppr->as_crypt
       $ppr->as_rfc2307
           These methods are part of the standard Authen::Passphrase interface.

SEE ALSO

       Authen::Passphrase, Digest::MD5

AUTHOR

       Andrew Main (Zefram) <zefram@fysh.org>

COPYRIGHT

       Copyright (C) 2006, 2007, 2009, 2010, 2012 Andrew Main (Zefram) <zefram@fysh.org>

LICENSE

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