Mechanisms to Mitigate Wireless Privacy Threats

The proliferation of mobile wireless devices enables or magnifies several privacy threats that traditional link layer confidentiality mechanisms, such as payload encryption, do not protect against: user tracking, profiling, and traffic analysis. For example, it is well known that the exposure of long-lived, unique device addresses can be used to track users over time. Although these addresses can easily be changed, more subtle features exposed in encrypted link layer traffic can be used to identify and profile users as well. These features, which we call implicit identifiers, include identifiers used for service discovery, characteristics that encryption does not obscure, and protocol information in unencrypted headers. We propose mechanisms to remove these features from wireless link layer protocols without the loss of important network functionality.