Digest MD5 Reverseでmd5を復号する方法

cd /usr/ports/security/p5-Digest-MD5-Reverse
sudo make install clean

#!/usr/local/bin/perl
use strict;
use warnings;
# MD5 ("a") = 0cc175b9c0f1b6a831c399e269772661
use Digest::MD5::Reverse qw(r_md5_hex);
my $md5 = '0cc175b9c0f1b6a831c399e269772661';
my $text = r_md5_hex ($md5);
print 'Data is ', $text, "\n";

time perl md5r.pl
Data is a

Time spent in user mode   (CPU seconds) : 0.178s
Time spent in kernel mode (CPU seconds) : 0.031s
Total time                              : 0:00.99s
CPU utilisation (percentage)            : 20.2%
Times the process was swapped           : 0
Times of major page faults              : 0
Times of minor page faults              : 459