Chirson PC Immobiliser

  • Editors' rating
    7.3 Very good


  • Easy to use
  • about as secure as a third-party product can be
  • good support for corporate deployment.


  • Could be cheaper.

The Chirson PC Immobiliser provides extra security for PCs and notebooks by blocking access except to someone who knows the system password, or who has the correct encrypted token. Installation may be daunting for novices, but it includes features that will make it simple for IT managers.

PC Immobiliser includes a software installation CD and a reassuringly robust-looking key fob. This fob is in fact an iButton. The iButton, made by US firm Dallas Semiconductor, is a computer chip enclosed in a tiny stainless steel can about the size of a fingernail. It’s rugged enough to survive dips in the ocean, careless feet and pretty much anything you care to throw at it. An iButton has only two contacts (the lid and the base), and the tiny chip contained communicates with the outside world via a serial interface.

But all you really need to know it that the iButton is both durable and secure. Each chip has a unique number laser-etched onto it, and this number is destroyed if the can is tampered with, making it very difficult to spoof one of these devices.

Installation is relatively straightforward, but -– as with so many things -- it's easier when you know how. With a product like PC Immobiliser, which locks access to a PC, the option on the first installation that says ‘Read manual’ should be considered an instruction.

Aside from the software, PC Immobiliser comprises two parts: the iButton keyfob and an iButton Blue Dot reader into which the iButton plugs. This device connects to the serial port of a PC, although Chirson also sells a USB version of the iButton that plugs directly into a PC or notebook.

Following installation and a system reboot, the first job is to register the software against the supplied iButton. The single-user iButton can only be used for one PC, while a Java-powered token can be used to register many PCs -- something a corporate IT manager might want to do. In the latter case, a regular iButton can then be matched to the PC for day-to-day access by the user. Java iButtons (also known as master tokens) also have the benefit that the PC can be ‘unregistered’ and the licence transferred back to the iButton for future use. Each master token can store up to 4,000 licences.

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Once everything is set up, the PC can be locked simply by removing the iButton. After a user-definable delay, the PC locks up and can only be unlocked either by re-inserting the iButton or by typing in a password that was chosen during the setup procedure.

PC Immobiliser can have an adverse effect on a PC due to the fact that it continually polls serial, parallel and USB ports to check that the iButton is still inserted. If another process does interrupt this polling, then the system could hang or the screen could flash, but Chrison says everything should return to normal as soon as the iButton is discovered again. This problem did not occur during ZDNet’s tests.

The main idea behind PC Immobiliser is to stop unauthorised access to a PC or notebook, but it’s also intended to make a PC -- and particularly a notebook -- a less attractive target for thieves. To this end, the product comes with a large sticker and second, larger key fob warning that the system is immobilised. Of course, any software-based security can be sidestepped simply by bypassing the software -- booting from a floppy, for instance. The PC Immobiliser installation prevents access to the command line during boot, and as soon as Windows fires up the system is protected. Chirson also provides a rough guide in the manual to setting a BIOS password that can make such strategies much more difficult, and operates a ‘reward for return’ scheme.

PC Immobiliser covers just about all bases that a third-party security product can. It’s not cheap, but it will make any system much more difficult to compromise -- not to mention less attractive to steal.