Wireless PC Lock – part 2

Over the last several days, I’ve been getting more and more requests for my updated Wireless PC Lock software that I described way back last year.

Possibly, it’s because of stories like this one:

At New York-based Big Four accounting firm Ernst & Young, the security department confiscates laptops if they are unlocked when not in use, say employees (who wish to remain anonymous). To reclaim the confiscated PCs, workers must explain why they forgot to lock their machines and then they get a quick refresher course in security. These employees say they dread that walk to IT, so many have gotten better at remembering to lock them.

Well, that’s a really amusing story, and I will confess that at my workplace, any workstation found unlocked tends to be used to invite the rest of the team out for lunch – you don’t forget to lock your workstation too often [whether that’s because lunch for a whole team is expensive, or because you just don’t want to have to spend an hour with your colleagues, is beyond me].

I work in a physically-secured building, where RFID cards have to be used to get in and out, but the problem of locked workstations is still an important one to us – the data that I can access is quite different from the data that can be accessed by the people across the hall, or by the people in other buildings. And if any inappropriate data access occurs from my workstation under my account, it’ll be my job that’s on the line – nobody’s going to try dusting for fingerprints to check that it wasn’t me.

So, I like to have an ‘insurance policy’ against forgetting that simple Windows-L keystroke. My insurance policy is the Wireless PC Lock, which detects when I get up and walk out of range, locking my computer if I haven’t already done so.

The crap software that comes with the Wireless PC Lock is a problem, though. It requires to be installed, which I don’t want (because I’m a restricted user); it doesn’t really lock the workstation (it puts up a full-screen bitmap of dolphins); it unlocks the workstation when you get back in range (even when it’s on the other side of a wall); etc, etc.

So, I decided it would be handy to have some replacement software that could be installed / used on a per-user basis. For the first release, this is strictly personal software – there’s no install. You copy the EXE into place, and run it from startup.

Insert the USB stick into your system and away we go. Right-click the new icon in your system tray (it looks a little like the transmitter fob on my unit – yours may be different), and choose to register with your fob.

The program will ask you to turn the fob off and then on again, so that it knows whose fob to lock against; once you have this set, that may be all the configuration you need to do – but of course, I have added configuration for the timeouts.

And, if you go and visit your Windows sound schemes, you’ll find there are additional sounds for the Wireless PC Lock, allowing you to hear when you’re about to get locked out by an absence of wireless fob.

Obviously, this is a real lock of your workstation that’s going to happen, so you will, yes, have to type in your password every time you come back to your workstation – your fob carries a two-byte code, which is not nearly difficult enough to hack to make it a valid logon protector. Sorry.

If you lose your fob, or your fob loses batteries, don’t worry – you can use your password to unlock, as usual, and then once you’re unlocked, the Wireless PC Lock software won’t activate again until it registers the presence of your fob again. Just remember that the Wireless PC Lock is a convenience measure, and is a “backup” against you forgetting to press Windows-L to lock up your machine when you’re walking away from it.

I’ve attached a zip file containing the Wireless PC Lock application – please let me know what you think of it!

22 thoughts on “Wireless PC Lock – part 2”

  1. Hey Dude, neat idea. WIBNIF… I always connect my Windows Mobile to my computer whenever I’m at my desk (at work). When I leave my desk I always take my phone with me. I’d love an option similar to yours in ActiveSync 🙂 Ooh, and maybe an option to send a lock signal over wi-fi from phone to computer also…

  2. I shall have to see what I can do.
    I’ve been asked about Bluetooth – but there are a couple of problems with using a Blue-tooth device to signal presence, not the least of which is that BlueTooth has an impressive range on occasion. For instance, in my office, I can use my earpiece in the cafeteria to hear music playing from my laptop’s BlueTooth adapter back at my desk: that’s too far of a connection to be useful.
    For a phone with a docking cradle, though, that’s probably a really good choice – and might be sufficiently secure an authentifier to work up a version that logs you on or unlocks you (Vista and later only – I don’t fancy a GINA rewrite)!

  3. Even though there’s no API call to do it, it is possible to unlock the workstation programmatically by emulating entering the password. I made a similar application that does this by connecting to an UltraVNC server service on the same host and sending mouse and keystroke events to enter the password. Alas, I have no hardware for proximity detection, so my application uses the removal and insertion of a USB drive holding a key file.

  4. Excellent. Thank you. I was getting ready to return the setup until I found your software. Thank you for taking the time to write this, and most importantly, distribute it.

  5. You’re very welcome. I will confess that I need to start polishing up the projects I’ve been working on, and release them here. Look for more security-related tools as time goes by – they won’t necessarily be polished sale-quality merchandise with install scripts, logos, etc, but they will be workable demonstrations like this one.

  6. Sure – when the program first runs, it registers as a source of application sounds. You can choose what sounds (if any) to use for any of the application’s events that are registered for sounds. You can do this from the Sounds Control Panel Applet.

  7. I will try this once I get a new battery for the key fob. Someone raised the question earlier about a similar system using Bluetooth and a cellphone and it looks like http://www.blueguardian.com have come up with something along those lines. I guess I will try that one too!

  8. This is great. I also packaged this up to return, until I came across your site.

    Would you be willing to release the code? I would like to modify this to work on Windows Vista.


  9. Would you make the source code available for download by any chance so people may adapt it to other platforms ?

  10. i can provide you with the code to allow auto un-lock when you come back to the machine, if this would save you time, all it would involve is storing a local encrypted copy of the password and restoring when needed.

    Auto-unlock with encrypted password

    Maybe on a different project, but not for this one – a couple of reasons:

    • The Wireless PC Lock has only two bytes of key on it, so it’s not all that secure or unlikely to compromise or accidental duplication
    • Encrypting the password should generally only be done using external keying material, or it’s easy to decrypt.
    Monday, March 09, 2009 05:45 AM by Alun Jones
  11. Hello, Alun – Thank you for this nice freebie. It doesn’t seem to be registering sounds on Windows 7.7100. It would be OK with me if it didn’t make any sound at all. How do I disable the sound from this app?

  12. heya. Brilliant software! Any chance you can distribute an compiled copy that does auto un-lock upon return? (even with the risks)

  13. Any chance of a link to the source code please as i have one of these devices and would like to write my own application for it. All i realy need is how to talk to the USB dongle.

    Thanks in advance.

  14. hi there, this is a great bit of software, i would love to make my own version of this, is there any chance of the code? or at least some info on how you talked to the usb? something like a DLL for it would be great.

    thanks again this is some awesome work, well done!

  15. Hi there, this is a real nice peace of software. let’s me use my (years old, and never used) pclock hardware on my shine brand new windows 7 netbook.

    there is another project for the harware called ‘USB Wireless Security’ which has less features than this soft but the sourcecode is made available. you can find it here: http://sourceforge.net/projects/usbwisec/


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