Perl script to generate encrypted password for Mac OS X.

password.pl

#!/usr/bin/perl
# Gavin Brock (http://brock-family.org/gavin/perl) - June 2007
#==============================================================================#

use strict;
use warnings;
use Foundation;

#==============================================================================#

sub kcpassword_xor {
        my ($pass) = @_;

        ### The magic 11 bytes - these are just repeated 
        # 0x7D 0x89 0x52 0x23 0xD2 0xBC 0xDD 0xEA 0xA3 0xB9 0x1F
        my @key = qw( 125 137 82 35 210 188 221 234 163 185 31 );

        my $key     = pack "C*", @key;
        my $key_len = length $key;

        for (my $n=0; $n<length($pass); $n+=$key_len) {
                substr($pass,$n,$key_len) ^= $key;
        }

        return $pass;
}

#==============================================================================#

sub write_pass {
        my ($enc) = @_;
        my $file = './kcpassword.txt';
        open(my $kcp, '>', $file) || die;
        print $kcp $enc;
        close($kcp);
        chmod(0600, $file);
}

#==============================================================================#

sub set_loginwindow {
        my ($user) = @_;
        my $uid  = getpwnam($user) || die;
        my $file = '/Library/Preferences/com.apple.loginwindow.plist';

        $user = NSString->stringWithCString_($user);
        $uid  = NSNumber->numberWithLong_($uid);

        my $plist = NSMutableDictionary->dictionaryWithContentsOfFile_($file);
        die unless $plist && $$plist;
        $plist->setObject_forKey_($user, "lastUserName");
        $plist->setObject_forKey_($user, "autoLoginUser");
        $plist->setObject_forKey_($uid, "autoLoginUserUID");
        $plist->writeToFile_atomically_($file, 0);
}

#==============================================================================#

my $user = "your_username";
my $pass = "your_password";
my $enc  = kcpassword_xor($pass);

write_pass($enc);
set_loginwindow($user);

system('killall','loginwindow');

exit 0;

#==============================================================================#