Secure Multimedia Transmission over RTP

The evolution of wireless handsets from simple mobile phones to smart devices, capable of capturing multimedia information and accessing Internet, has enabled its users to share multimedia contents with other network-capable devices in the vicinity or across the Internet. However, multimedia contents may include private information that a user may share only if it is secure from sniffing and other digital attacks.Achieving security by fully encrypting multimedia contents is not a viable solution for mobile devices, as they run on limited battery power and employ relatively slower processors compared to their desktop counterparts. These limitations have forced the handsets manufacturers to move the security operations to other parts of the networks thus compromising scalability as well as privacy. This paper presents a highly scalable approach for securing multimedia streams on mobile devices by encrypting intelligently selected portions of the coded bit stream.The proposed solution does not require media decoding and encrypts on the average less than 1% of the packet load. For all practical purposes, the proposed scheme provides robust security equivalent to that of a fully encrypted bit stream. The proposed scheme has been implemented on Nokia devices running Maemo, a mobile version of Debian distribution.