Biblio

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.

Due to the development of cloud computing and NoSQL database, more and more sensitive information are stored in NoSQL databases, which exposes quite a lot security vulnerabilities. This paper discusses security features of MongoDB database and proposes a transparent middleware implementation. The analysis of experiment results show that this transparent middleware can efficiently encrypt sensitive data specified by users on a dataset level. Existing application systems do not need too many modifications in order to apply this middleware.