Biblio

This paper is concerned with three ensembles of systematic low density generator matrix (LDGM) codes, all of which were provably capacity-achieving in terms of bit error rate (BER). This, however, does not necessarily imply that they achieve the capacity in terms of frame error rate (FER), as seen from a counterexample constructed in this paper. We then show that the first and second ensembles are capacity-achieving under list decoding over binary-input output symmetric (BIOS) memoryless channels. We point out that, in principle, the equivocation due to list decoding can be removed with negligible rate loss by the use of the concatenated codes. Simulation results show that the considered convolutional (spatially-coupled) LDGM code is capacity-approaching with an iterative belief propagation decoding algorithm.

Security and privacy issues of the Internet of Things (IoT in short, hereafter) attracts the hot topic of researches through these years. As the relationship between user and server become more complicated than before, the existing security solutions might not provide exhaustive securities in IoT environment and novel solutions become new research challenges, e.g., the solutions based on symmetric cryptosystems are unsuited to handle with the occasion that decryption is only allowed in specific time range. In this paper, a new scalable one-time file encryption scheme combines reliable cryptographic techniques, which is named OTFEP, is proposed to satisfy specialized security requirements. One of OTFEP's key features is that it offers a mechanism to protect files in the database from arbitrary visiting from system manager or third-party auditors. OTFEP uses two different approaches to deal with relatively small file and stream file. Moreover, OTFEP supports good node scalability and secure key distribution mechanism. Based on its practical security and performance, OTFEP can be considered in specific IoT devices where one-time file encryption is necessary.