Interval-Based Spread Spectrum Watermarks for tracing multiple network flows

Most existing timing-based and traffic rate-based watermarking schemes are ineffective at tracing multiple network flows in parallel due to their interference with each other, even worse, most of them are visible to multi-flow attack and/or MSAC attack, as they embed different network flows using the same interval positions and/or improper parameters. By combining Interval-Based Watermarking (IBW) modulation approach with Spread Spectrum (SS) coding technique, we propose an Interval-Based Spread Spectrum Watermarking (IBSSW) scheme for tracing multiple network flows efficiently and simultaneously, which embeds signal by modulating the statistical character of packets arriving time and utilizes multiple orthogonal Pseudo-Noise (PN) codes as random seeds for randomizing the locations of the embedded watermark across different network flows. A statistical analysis of IBSSW, with no assumptions or limitations concerning the distribution of packet times, proves its effectiveness of multi-flow traceback under conditions of repacketization and timing perturbation, and robustness against multi-flow and MSAC attacks. Empirical results demonstrate that IBSSW can efficiently trace multiple network traffic at the same time.