@ca = (sub {
    @kp = split(//, shift @_, 0);
    $c = shift @_;
    $p2{' '} = ' ';
    $C2{' '} = ' ';
    foreach $_ (@kp, ('a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z')) {
        if (not exists $p2{$_}) {
            $k = chr 65 + ($a++ + $c) % 26;
            $p2{$_} = $k;
            $C2{$k} = $_;
        }
    }
}
, sub {
    $t = shift @_;
    $h = shift @_;
    foreach $_ (split(//, $t, 0)) {
        $r = $r . $$h{$_};
    }
    return $r;
}
);
$ca[0]->('thequickbrownfoxjumpsoverthelazydogs', 10);
print $ca[1]->('ZOCK FWUKLMT BMTE LFQR', \%C2) . "\n";

##</code><code>##

# @ca - code array
# @kp - key phrase
# $c  - caesar shift (big hint here)
# %p2 - short for p2C - plaintext to CIPHERTEXT hash
# %C2 - short for C2p - CIPHERTEXT to plaintext hash
# $k  - key (one letter of the key alphabet)
# $t  - text
# $h  - hash reference
# $r  - result