use Crypt::Blowfish;

my $key = 'ThisIsMyKey';
my $cipher = Crypt::Blowfish->new($key);
my $buffer;
my $file = 'TestFile.txt';
open(my $in,  "<", $file) or die "Couldn't open '$file' for read: $!";
open(my $out, ">", "$file.crypt") or die "Couldn't open '$file.crypt' for write: $!";
while( read($in, $buffer, 8) ) {
        if ( length($buffer) < 8 ) {
                for (1..8-length($buffer)) {
                        $buffer.=chr(0);
                        print length($buffer);
                }
        }
        print $out $cipher->encrypt($buffer);
}

##</code><code>##

my $key = 'ThisIsMyKey';
my $cipher = Crypt::Blowfish->new($key);
my $buffer;
my $file = 'TestFile.txt';
open(my $in,  "<", "$file.crypt") or die "Couldn't open '$file' for read: $!";
open(my $out, ">", "$file.decrypt") or die "Couldn't open '$file.decrypt' for write: $!";
while( read($in, $buffer, 8) ) {
        print $out $cipher->decrypt($buffer);
}