However, London-based Privacy International says it has identified several potential methods for covertly tracking the locations of mobile devices without the knowledge or consent of their users.

"Many people will see Latitude as a cool product, but the reality is that Google has yet again failed to deliver strong privacy and security ," said Privacy International Director Simon Davies. "The company has a long way to go before it can capture the trust of phone users."

Covert Scenarios

Google sees Latitude as a boon for individuals who want to provide family members, friends and business associates with up-to-date information on their locations. To address privacy concerns, the search giant said it has adopted an opt-in policy under which both the mobile-phone user and the tracker must grant consent.

Google also said it has taken great care to build "fine-grained privacy controls" into the application. "Everything about Latitude is opt-in," said Vic Gundotra, a vice president of engineering on the Google mobile team. "You not only control exactly who gets to see your location, but you also decide the location that they see."

Furthermore, the Google Latitude privacy menu gives the user the ability to either detect and share the handset's location automatically, set the device's location manually, hide its location, or turn off Latitude altogether. Still, Privacy International sees several holes in Google's privacy strategy.

For example, the privacy watchdog said enterprises could provide their workers with phones on which Google Latitude has already been enabled, allowing the movements of staff members to be tracked by senior management without their knowledge. Any phone left unattended would be vulnerable to having Google Latitude installed without the knowledge of the handset's owner, the group warned. Additionally, phones given as gifts would potentially be subject to the same privacy violations.

Masking Movements

The documentation for Google Latitude says users can mask their movements any time they wish. "You can hide your current location from all friends or from individual friends at any time," Google said. "When you hide your location, your friends will not see your photo icon on a map and will not see a location for you in their list view."

But Privacy International warns that the same masking technology could be used by others to prevent smartphone users from realizing they are being tracked.

"The only means of minimizing this threat might be a regular message sent to a phone advising that it has been Latitude-enabled," the watchdog said. "However, according to Google, this function is available only in certain circumstances" and may only apply to "certain unspecified phone types."

As it stands now, Davies noted, Latitude could be a gift to stalkers, prying employers, jealous partners, and obsessive friends. "The dangers to a user's privacy and security are as limitless as the imagination of those who would abuse this technology," Davies said.