I'm totally baffled. I don't understand why I see an encryption error when trying to encrypt a single character password from a Tk GUI like so:

use strict;
use warnings;
use Tk;
use Crypt::CBC;

my $plaintext;
my $mw = MainWindow->new();

my $password_e = $mw->Entry( 
    -textvariable => \$plaintext,
    -show => '*',
    -width   => '10'
)->pack( -side => 'top');

my $password_b = $mw->Button(
        -text    => "Encrypt",
        -width   => '13',
        -command => \&encrypt
    )->pack( -side => 'top', -pady => 10 );

sub encrypt {

    my $key = pack("H16", "0123456789ABCDEF");
    print("$plaintext\n");

    my $cipher = Crypt::CBC->new(
    -cipher => 'DES',
    -key    => $key,
    );

    my $ciphertext = $cipher->encrypt($plaintext);
    print("$ciphertext\n");

    my $recovered = $cipher->decrypt($ciphertext);
    print("$recovered\n");

}



MainLoop
[download]

This code works fine for a single charcter:

    my $plaintext = 'P';
    
    my $key = pack("H16", "0123456789ABCDEF");
    print("$plaintext\n");

    my $cipher = Crypt::CBC->new(
    -cipher => 'DES',
    -key    => $key,
    );

    my $ciphertext = $cipher->encrypt($plaintext);
    print("$ciphertext\n");

    my $recovered = $cipher->decrypt($ciphertext);
    print("$recovered\n");
[download]

Any idea why?

2006-10-12 Retitled by g0n, as per Monastery guidelines
Original title: 'Tk Error Mystery'

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