oracular (3) Digest::MultiHash.3pm.gz

NAME

       Digest::MultiHash - XOR based, variable width multiplexing of hashes (a generalized Digest::SV1).

SYNOPSIS

               use Digest::MultiHash;

               my $d = Digest::Multihash->new(
                       width => 16, # bytes
                       hashs => ["SHA-512", "Whirlpool"], # see below for arbitrary arguments
               );

               $d->add($data);

               print $d->hexdigest;

DESCRIPTION

       This class inherits from Digest::base, and provides generalized digest multiplexing.

       It will multiplex all calls to "add" to all of it's sub digest objects.  Likewise, when the final digest
       is extracted the digests will be extracted and then XOR'd over eachother according to "width".

       "width" will default to the width of the first hash if unspecified.

       "hashes" defaults to "SHA-1" for compatibility reasons.

       This module is useful for generating keys from passphrases, by supplying the desired width and simply
       making sure there is enough data from the combined hashes.

METHODS

       See Digest for the complete API. This module inherits from Digest::base.

       new This methods accepts a hash reference or an even sized list of parameters named according to the
           methods.

       add
       digest
           Compute the hash by calling "digest" on all of the subhashes, splitting the result up into "width"
           sized chunk, and then XORing these together.

           If the result is not aligned on "width" the result will not be truncated. The shorter string will
           still be XOR'd with the hash, even if this only affects part of the result.

           If there are not at least "width" bytes of data in the output of the combined hashes an error is
           thrown.

       clone
           Clones the hash.

       hashes
           Get the array of hashes to use. Array values in this will be dereferenced before the call to "new" in
           Digest to allow passing of arbitrary arguments.  Blessed objects (of any class) will be used
           verbatim.

           The list of hashes cannot be changed after construction.

       width
           Get/set the byte-width to use.

SEE ALSO

       Digest, Digest::SV1, Digest::SHA1