Google Latitude, Loopt and Brightkite are location-based search services that help users find friends, businesses and other information from their mobile and wireless devices. The Electronic Frontier Foundation offers a whitepaper on how these services can use cryptographic security to protect consumer privacy. The challenges are great, but they argue the results will be worth it in ensuring users' locational privacy.
Many users love geo-location services such as Google Latitude
, which leverage GPS data and wireless networks to help users find
their friends, businesses or other areas of interest from their smartphones.
Such services also scare some users because they mean our
location information is stored in a database. What if we want a user or service
provider to know where we are, but not have that information stored in the location-based service
A privacy expert and a mathematician have proposed such
services that ensure users' locational privacy are possible.
In a whitepaper,
"On Locational Privacy, and How to Avoid Losing it Forever
," Peter Eckersley,
staff technologist for the Electronic Frontier Foundation, and Andrew Blumberg,
a postdoctoral fellow at Stanford University, argue that modern cryptography allows
data processing systems to be designed with privacy policies ranging from limited
to complete anonymity.
"Preserving locational privacy is about maintaining
dignity and confidence as you move through the world," the researchers
wrote. "Locational privacy is also about knowing when other people know things
about you, and being able to tell when they are making decisions based on those
The researchers argue modern cryptography will let
companies deploy anything from road tolls and transit tickets to location
searches from cell phones and all the other mobile services we want without
creating a record of where users are.
Eckersley and Blumberg offer the case of location-based
search services on mobile devices as an important example. Because phones are locating
themselves based on the signal strength or visibility of nearby wireless
networks or on GPS data, companies are trying to provide search tools which use
this data to offer people different search results depending on where they are
at any given moment.
For example, if a user is on Folsom Street in San Francisco
and does a search for local restaurants, a service would return search results
for eateries within a half-mile radius of Folsom Street. The researchers provide an
example of a location search that does not ensure privacy because it allows for
The naive way to do mobile location search is for the
device to say "This is Frank's Nokia here. I see the following five Wi-Fi
networks with the following five signal strengths." The service replies
"OK, that means you're at the corner of 5th and Main in
Springfield." Then your device replies, "What burger joints are
nearby? Are any of Frank's friends hanging out nearby?" That kind of
search creates a record of everywhere you go and what you're searching for
while you're there.
The researchers claim the cryptographic way to blend location-based
services and search would sound like this: