NAME
Data::Digest - Objects that represent a digest values
SYNOPSIS
$digest = Data::Digest->new(
'MD5.d41d8cd98f00b204e9800998ecf8427e'
);
$digest = Data::Digest->new(
'SHA-256' => '47DEQpj8HBSa+/TImW+5JCeuQeRkm5NMpJWZG3hSuFU',
);
$digest->matches( \$data );
$digest->matches( $filename );
DESCRIPTION
The "Data::Digest" class provides utility objects that represents a
digest value. It is used primarily as a convenience and to simplify code
when dealing with situations where you are provided with a digest, and
need to check it against some data.
It initially supports 4 different digest types, (MD5, SHA-1, SHA-256 and
SHA-512) to provide varying strengths of checking. The default, which is
intended for speed and basic non-cryptographic file integrity checking,
is MD5.
Users hand-crafting guest specifications may want to use a stronger
digest.
METHODS
new
# Two-argument digest constructor
$digest = Data::Digest->new(
'SHA-256' => '47DEQpj8HBSa+/TImW+5JCeuQeRkm5NMpJWZG3hSuFU',
);
# One-argument digest constructor
$digest = Data::Digest->new(
'MD5.d41d8cd98f00b204e9800998ecf8427e'
);
The "new" constructor takes one or two strings parameters, and creates a
new digest object, that can be stored or used to compared the digest
value to existing data, or a file.
The basic two-argument form takes the name of a supported digest driver,
and the digest value.
The digest driver is case sensitive and should be one of 'MD5', 'SHA-1',
'SHA-256' or 'SHA-512'. (case sensitive)
The second param should be a string containing the value of the digest
in either binary, hexidecimal or base 64 format.
The constructor will auto-detect the encoding type.
For example, for a 128-bit MD5 digest, the constructor will allow a
16-character binary string, a 32-character hexedecimal string, or a
22-character base 64 string.
Returns a "Data::Digest" object, or throws an exception on error.
driver
The "driver" accessor returns the digest driver name, which be one of
either 'MD5', 'SHA-1', 'SHA-256' or 'SHA-512'.
digest
The "digest" accessor returns the digest value, in the original format.
This could be either binary, hexidecimal or base 64 and without knowing
what was originally entered you may not necesarily know which it will
be.
as_string
The "as_string" method returns the stringified form of the digest, which
will be equivalent to and suitable for use as the value passed to the
single-parameter form of the constructor.
print $digest->as_string . "\n";
> MD5.d41d8cd98f00b204e9800998ecf8427e
Returns a string between around 15 and 90 characters, depending on the
type and encoding of the digest value.
matches
# Check the digest against something
$digest->matches( $filename );
$digest->matches( $io_handle );
$digest->matches( \$string );
The "matches" methods checks the digest object against various forms of
arbitrary data to determine if they match the digest.
It takes a single parameter, consisting of either the name of a file, an
IO::Handle object, or the reference to a "SCALAR" string.
Returns true if the digest matches the data, false if not, or throws an
exception on error.
SUPPORT
Bugs should be reported via the CPAN bug tracker at
<
http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Data-Digest>
For other issues, contact the author.
AUTHOR
Adam Kennedy <
[email protected]>
SEE ALSO
Digest, Digest::MD5, Digest::SHA
COPYRIGHT
Copyright 2006 - 2008 Adam Kennedy.
This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
The full text of the license can be found in the LICENSE file included
with this module.
