In present, almost all of inline code dissemination algorithms focus on securing the propagation of code images and overlook the security vulnerabilities in the image management aspects of code dissemination, such as rebooting and erasing code images. In this paper, we first investigate the security issues in remote image management for code dissemination in wireless sensor networks and analyze the advantage and disadvantage of the algorithm proposed by Liu et al which employs three different key chains to design three different schemes. To reduce the computation load of authentication operation, a message cipher puzzle-based image management algorithm is proposed. In this approach, a one-way hash key chain is introduced to authenticate the Reboot and Erase command and a weak authentication mechanism is introduced to protect the version number. The message cipher puzzle-based authentication method is efficient, because it only introduces a few hash function operations and comparisons

Mobile communication technologies have been widely utilized in daily lives, many low-computing-power and weakly-structured-storage devices have emerged, such as PDA, cell phones and smart cards, etc. How to solve the security problems in such devices has become a key problem in secure mobile communication. In this paper, we would like to propose an efficient signature-encryption scheme. The security of the signature part is not loosely related to Discrete Logarithm Problem (DLP) assumption as most of the traditional schemes but tightly related to the Decisional Diffie-Hellman Problem (DDHP) assumption in the Random Oracle Models. Different from the existing solutions, our scheme introduces a trusted agent of the receiver who can filter the “rubbish” messages beforehand. Thus, with high efficiency in computation and storage, it is particularly suitable for the above mobile devices with severely constrained resources and can satisfy the security requirements of mobile computations.

Based on previous research, this paper puts forward a kind of routing protocol based on node convergence degree and the trust value which named BCDTV. We focus on algorithm design and work process, including the election of cluster head and the establishment of cluster, the collection and transmission of the information. We use the gradational design algorithm when calculation the trust of every nodes. Simulation results show that the protocol can prevent some malicious behavior of malicious nodes effectively.