Many companies' protection against hackers and viruses may not go far enough Phillip Coombes says the next step is fibre intrusion technology.

Recent high-profile security incidents, such as the wireless LAN (Local Area Network) security scare, in which hackers fooled wireless network users into logging onto rogue access points ('evil twins') set up to emulate legitimate wireless LAN equipment, have encouraged more businesses to consider the potential threats to the network cabling infrastructure of a building. Many have measures in place to protect themselves against hackers and viruses, but does this go far enough?

The threat of an intruder tapping into communication lines coming into and going out of a building is a serious issue which is often not addressed.

An intruder trying to break into a building may be picked up on CCTV, but tapping a phone line or intercepting an e-mail is more difficult to detect and could go unnoticed. Key security threats include manhole covers, which represent easy access points for potential intruders, and data tap devices, which are legally available to the man on the street and allow people to monitor a line without interrupting the flow of data. Businesses need to be aware of this kind of threat - and consider taking measures to protect themselves.

Role of fibre optics

Fibre intrusion technology offers a good solution to securing the flow of information and the business itself from these types of intrusion.

The security industry has begun adopting fibre optic cables as a more secure alternative to conventional copper cables, as they are more difficult to tap into. However, there is a more advanced technology available, which employs optical fibres as a sensing device for measuring attributes such as movement, pressure, strain, temperature and even audible sound. It is this application which currently has the security industry very excited, as it has the potential to replace many existing electrical and mechanical sensing technologies and is a far more reliable form of detection.

By employing fibres within the actual data cable as a sensor, the entire cable length can be easily monitored for illegal data taps or disturbance - deliberate or accidental - making it easy to detect if the flow of data is interfered with. This type of network security monitoring system can detect intrusion attempts to within 50 metres along data networks up to 60km long and is fully automated to provide early warnings of tampering or interference.

The fibre optic sensors work by detecting minute vibrations and movements via deflections in the laser light beam that runs down the fibre. By using advanced signal processing and analysis, the different causes of events, and more importantly the location, can be identified, and those attributable to false alarms can be eliminated.

Two basic types of fibre optic sensing technologies are commonly used - the fibre optic continuity or 'trip-wire', which requires the actual fibre optic strand to be broken in order to initiate an intrusion alarm, and fibre optic microbending, which detects alterations in the light pattern caused by any minute movement of the fibre optical cable.

Fibre optic continuity

The fibre optic continuity sensor is similar to any closed loop device.

As long as the sensor cable remains intact, with light passing from the transmitter to the receiver, no alarm is triggered. If the cable is broken, the signal transmission ceases and an alarm is generated.

There are however a few disadvantages with this type of cable. After every intrusion, the cable has to be either repaired or replaced before the system can be made operational again. There is also no intelligence in the system to analyse the signals and eliminate the causes of false alarms or to determine the severity of the intrusion.

In the case of fibre optic micro bending or disturbance, the cable must be minutely bent or disturbed to affect the light being transmitted and thereby signal a disturbance along the sensor.

The fibre optic cable acts as a distributed sensor and contains an electro-optics unit, which transmits light using an LED (Light Emitting Diodes) or laser for the light source. The light travels through the fibre and is picked up by the detector, which is very sensitive to slight alterations in the light transmission caused by vibrations to the cable. This method is useful for detecting if any monitoring or listening device is being linked up to the cable.

Buried installations

Cables designed specifically for intrusion detection are also an effective method to employ and run alongside your network infrastructure and can be a more cost effective method of detecting the minute pressures and earth movements generated by human traffic and intrusion attempts.

This type of fibre optic sensor can also be buried alongside oil and gas pipelines to provide early warning of illegal pipeline tapping activities and third party interference.

Ensuring data integrity

With the increase in remote and mobile working, security of data has become a real concern for businesses. The hype surrounding the security of wireless networks should not detract from ensuring your cabling network is secure and the integrity of data remains intact as it travels through it.

Using fibre optic sensors to monitor cables is a very effective way of detecting intrusion. The fully automated system will take the pressure off the IT department, as it will be alerted immediately if someone touches the cable and will be able to pinpoint exactly where the interference has occurred.

The benefits of using this type of technology are clear, but take-up has been slow, with many businesses perceiving the cost and potential disruption to the business to be too high. More education is needed to ensure companies are aware of fibre intrusion technology and the benefits of using it as a form of data security.

- Phillip Coombes is managing director, Fibre Technologies Ltd, Tel: 01344 752222,