Modern adaptive image steganography with minimizing a distortion function has high performance of undetectability. However, when an image with hidden information is attacked by JPEG compression, its robustness cannot be guaranteed, that remarkably limits its extension from the lab to the real world. In this paper, a novel image steganographic algorithm is proposed that is robust to JPEG compression. First, by using the sign of DCT coefficients, that remains unchangeable before and after JPEG compression, we select the candidate coefficients for resisting JPEG compression. Second, the designed distortion function assigns cost for each candidate DCT coefficient. Finally, relying on both error correction code and Syndrome-Trellis Codes, an encoded message is embedded into the cover image with minimum embedding distortion. Compared with prior arts, extensive experimental results highlight both undetectability and robustness of our proposed algorithm. INDEX TERMS Robust steganography, distortion function, JPEG compression, sign of DCT coefficients.

No abstract

No abstract

No abstract

Self-monitoring is an important mechanism for the security of wireless sensor networks. In this work we propose a novel distributed node self-monitoring mechanism for wireless sensor networks. Assuming a sensor node can detect the communications (sending message) of its neighboring nodes, we design a one-to-many self-monitoring mechanism, in which the selected nodes, named Monitor Nodes (MNs), can monitor their neighboring nodes. A distributed dominating set approximation algorithm is design to obtain the MN set. The cooperation among MNs guarantees all regular nodes (RNs) are monitored. However, the MNs may be compromised by external attackers and produces false alarms. To improve the one-to-many selfmonitoring mechanism, we design a many-to-one dynamical monitoring approach to take the MNs under surveillance. The neighboring nodes of a MN are dynamically selected to monitor their MN. In the proposed mechanism, a node produces an alert when it detects abnormal behaviors of the node under surveillance. The sink node collects the alert messages to make judgment to the potential abnormal nodes. The proposed selfmonitoring mechanism can be used to detect and position multiple inter-network attacks, including selective forwarding, black-hole and DoS. Simulations demonstrate the effectiveness of the proposed node self-monitoring mechanism.978-1-4244-7618-3 /10/$26.00 ©2010 IEEE