Biblio

In recent years, Wireless Sensor Networks (WSNs) have become valuable assets to both the commercial and military communities with applications ranging from industrial control on a factory floor to reconnaissance of a hostile border. A typical WSN topology that applies to most applications allows sensors to act as data sources that forward their measurements to a central sink or base station (BS). The unique role of the BS makes it a natural target for an adversary that desires to achieve the most impactful attack possible against a WSN. An adversary may employ traffic analysis techniques such as evidence theory to identify the BS based on network traffic flow even when the WSN implements conventional security mechanisms. This motivates a need for WSN operators to achieve improved BS anonymity to protect the identity, role, and location of the BS. Many traffic analysis countermeasures have been proposed in literature, but are typically evaluated based on data traffic only, without considering the effects of network synchronization on anonymity performance. In this paper we use evidence theory analysis to examine the effects of WSN synchronization on BS anonymity by studying two commonly used protocols, Reference Broadcast Synchronization (RBS) and Timing-synch Protocol for Sensor Networks (TPSN).

The electric network frequency (ENF) signal can be captured in multimedia recordings due to electromagnetic influences from the power grid at the time of recording. Recent work has exploited the ENF signals for forensic applications, such as authenticating and detecting forgery of ENF-containing multimedia signals, and inferring their time and location of creation. In this paper, we explore a new potential of ENF signals for automatic synchronization of audio and video. The ENF signal as a time-varying random process can be used as a timing fingerprint of multimedia signals. Synchronization of audio and video recordings can be achieved by aligning their embedded ENF signals. We demonstrate the proposed scheme with two applications: multi-view video synchronization and synchronization of historical audio recordings. The experimental results show the ENF based synchronization approach is effective, and has the potential to solve problems that are intractable by other existing methods.