Why jammers in prisons is a joke

By Muthoga Kioni

Safaricom and Kenya Prisons Services recently announced that they would install phone-jamming equipment in all the major prisons.

This was termed as a response to the runaway crime involving mobile phones that is perpetuated by prisoners.

The strategy of jamming mobile phone signals in prison compounds is a logical technical response.

By creating islands of non-connectivity in these jails, it is possible to mitigate the economic and social risk posed by these incarcerated criminals.

Phone jamming is not a new phenomenon. In the past, it was associated with spy craft and the military.

Times have changed. Mobile phone jammers are now commercially available and widely used by ordinary citizens in countries that have legalised their usage.

Jamming a mobile phone basically entails the blocking of its frequency by using a device called a jammer.

Your mobile phone transmits a signal on a certain frequency so as to communicate with the service provider’s network.

The jammer will broadcast a signal to your mobile using this very same frequency. Once these two signals collide they cancel each other out and what results is a ‘No Network’ indicator on your mobile.

The range of a jammer depends on its power output and whether it is designed to disrupt mobiles or towers. Pocket/portable jammers typically operate in a range of about 9 metres.

Higher powered jammers operate in a range of up to 1.6 kilometres away from the device.

Choice determinant

The choice of which jammer to use is dependent on the range you wish to deploy it to.

To have uninterrupted meetings in an enclosed room, portable jammers are ideal.

In a restaurant or church, a medium power jammer would suffice.

For a prison compound, a very high powered jammer that can block multiple frequencies would be the ideal.

It is broadly agreed that something needs to be done to curb the acquisition of mobile phones by criminals in our local prisons.

However, the jamming of mobiles has been tried by other countries with varied success.

Of initial concern would be the fate of prison staff and family who live and work in these compounds.

To be able to effectively jam mobile phones in our expansive prisons, high powered jammers will have to be used.

This means that prison staff and other mobile users in the surrounding areas will also be inconvenienced.

Interference with critical public frequencies is another risk.

Public safety responders like ambulances, police and fire fighters use dedicated frequencies. High-powered jammers should be configured to ensure these frequencies are not interfered with.

It is also worth considering the legality of this implementation.

The Kenya Information and Communications Act – Section 45 states that interference with any radio communication would result in a fine not exceeding Sh1 million or a prison term not exceeding five years or both.

Other Alternatives

Combating the use of mobile phones by prisoners to propagate crime requires a multi-pronged approach. Jamming their mobiles, in itself, is not enough.

We should start by increasing the criminal penalty of smuggling mobiles into our prisons.

The penalty for this kind of crime should be extremely punitive to discourage prison staff and visitors from abetting the smuggling of mobiles.

Other technical measures that should be explored include handset disablers, micro-cells and Faraday cages.

Unlike jammers, handset disablers do not emit jamming signals.

They instead detect the presence of mobiles and prevent the making of any call. This detection and disabling is done by the software at the base station.

Attractive choice

What makes this alternative attractive is that it does not disable calls from ‘emergency users’.

Pre-selected mobile users, who have pre-registered their phone numbers with the service provider, are allowed to receive and make emergency calls.

Micro cells are essentially scaled down base stations. It would be possible to build micro cells dedicated to the prisons.

These cells would carry all traffic originating and terminating in the prison compound. In this implementation it is possible to segregate only prison calls and avoid jamming calls of legitimate users in the prison environs.

The micro cell would be able to intercept communications specific to the prison and disable the mobiles through either SIM or IMEI blocking.

Another alternative is the Faraday cage, which is a wire mesh enclosure that is grounded.

It provides a shield to radio waves. A cage round the main prison compound would impede the transmission of mobile phone signals to or from any handset located in the cage.

One critical lesson that needs to be internalised from this effort is that there is a slow but sure shift from conventional to cyber crime by Kenyan criminal elements.

The ingenuity and innovativeness exhibited in the execution of these mobile phone scams proves that it is only a matter of time before ICT security becomes a priority for law enforcement agencies.

-The writer is an ICT Security and Forensic Specialist. [email protected]