PN Code Diversification Based Spread Spectrum Flow Watermarking Technology

Compared with passive flow correlation technology, active flow watermarking technology has the advantages of high accuracy and low false positive rate in the aspects of stepping stone attack tracking and anonymous abuser association. Multi-flow attack can detect the existence of flow watermark, restore the flow watermark, and even remove the flow watermark from target watermarked flow. To improve the multi-flow attack resistance capability of flow rate-based direct sequence spread spectrum (DSSS) flow watermarking technology, a pseudo-noise (PN) code diversification based spread spectrum flow watermarking technology is proposed. Each watermark bit is spread by different PN code fragments before embedded into target flow, which can eliminate the inter-dependence between these watermarked flows and effectively defend against multi-flow attack. Compared with the embedding position randomization method, the complexity of our proposed technology is low and the false positive rate doesn't increase. Compared with the watermark bit reordering method, our proposed technology is more suitable for the DSSS flow watermarking technology and the multi-flow attack resistant effect is better.