Perl Cd Bookshelf [Electronic resources] نسخه متنی

8.58. Digest::MD5

The Digest::MD5 module allows simpler
creation of MD5 hashes. MD5 takes as input a message of arbitrary
length and creates a 128-bit fingerprint, or digest, of the input.
Like the Digest module, Digest::MD5 implements both a functional and
object-oriented interface, which offer the same benefits. Digest::MD5
also outputs binary (16 bytes long), hexadecimal (32 characters
long), and base64 (22 characters long) data.

To rewrite the example in
Section 8.57, "Digest":

#!/usr/local/bin/perl -w
# Yes, functional interface
use Digest::MD5 qw(md5_hex);
my $text = `Be the ball, Danny!'';
my $hexed = md5_hex($text);
print "The sum of \$text is [$hexed].\n";

You can use the object-oriented interface like so:

#!/usr/local/bin/perl -w
use Digest::MD5;
my $text = `Be the ball, Danny!'';
my $md5 = Digest::MD5->new();
$md5->add($text);
my $sum = $md5->hexdigest;
print "The sum of \$text is [$sum].\n";

Digest::MD5 implements (and exports) the following functions.

new()

Constructor. Returns a new Digest::MD5 object. You can add data to
$object and retrieve the digest itself. If you can
new more than once, it will reset the existing
digest and create a new Digest::MD5 object.

reset()

An alias for new.

add(data, ...)

Appends data to the message for which you
calculate the digest. add returns the Digest
object itself. For example:

open(FILE, ...) or ...
while (<FILE>) {
$md5->add($_);
} close(FILE);

addfile(io_handle)

Reads io_handle until end-of-file and
appends the content to the message for which you calculate the
digest. addfile returns the Digest object itself.
For example:

open(FILE, $file) or ...
print Digest::MD5->new->addfile(*FILE)->hexdigest, " $file\n";
close(FILE);

b64digest()

Same as digest, but returns the digest in
base64-encoded form.

digest()

Returns the binary digest for the message. Note that
digest is a destructive operation, in that the
Digest object is reset so it can be used to create another value.

hexdigest()

Same as digest, but returns digest in hexadecimal
form.

The following functions are implemented by the functional interface.

md5(data, ...) 

Calculates the MD5 digest of data and
returns it in binary form.

md5_base64(data,...)

Same as md5, but returns the digest as a
base64-encoded string.

md5_hex(data,...)

Same as md5, but returns the digest in hexadecimal
form.