The Electronic Frontier Foundation (EFF) is urging policy makers and engineers working with location-based systems to incorporate cryptography technology into their designs in order to protect individuals' privacy.

The Locational Privacy report from the US-based organisation points to the increasing prevalence of digital systems that track people's movements, ranging from travel cards to mobile phone GPS systems and electronic swipe cards for doors.

The EFF argues that "location privacy", which it defines as an individual's position not being tracked and covertly recorded for later use, has changed significantly in recent years without much legislation to protect the public.

While tracking an individual's whereabouts used to mean physically following them around, location-based services now track individuals with little cost and time, and usually without the individual knowing.

The EFF acknowledges that location-based services are useful and should not be banned, but believes that they need monitoring.

"What urgently needs to change is that these systems need to be built with privacy as part of their original design. We cannot afford to have pervasive surveillance technology built into our electronic civic infrastructure by accident. We have the opportunity now to ensure that these dangers are averted, " said the report.

"Modern cryptography actually allows civic data processing systems to be designed with a whole spectrum of privacy policies, ranging from complete anonymity to limited anonymity to support law enforcement.

"But we need to ensure that systems are not being built right at the zero-privacy, everything-is-recorded end of that spectrum, simply because that is the path of easiest implementation."

The EFF argues that the private sector will benefit from installing modern cryptographic protocols, even though it can pose an engineering challenge. Citizens are concerned about having their location tracked on a continual basis, and the ability to offer privacy protection will give vendors a competitive edge.

The private sector should also look at the kinds of cryptographic software that protect the security of financial networks, such as ATMs. Major software contractors, such as IBM and Siemens, employ large numbers of cryptographers, the report said.

The EFF warned that even if data collecting agencies promise to delete location data after collection, there is no guarantee that they will do this properly, and the public should campaign for the introduction of cryptography techniques.

"Firstly, secure deletion tools are necessary to make sure that deleted data is really gone, and many system administrators will fail to use them correctly. Secondly, all it takes is the flip of a switch to suddenly change policies from deletion to retention," said the EFF.

The report concludes that decisions about how much location data is protected should ideally be set by democratic action and lawmaking, but that organisations designing such services should take the initiative and protect public privacy in the meantime.