With the dramatically increasing deployment of IoT devices, storing and protecting the large volume of IoT data has become a significant issue. Traditional cloud-based IoT structures impose extremely high computation and storage demands on the cloud servers. Meanwhile, the strong dependencies on the centralized servers bring significant trust issues. To mitigate these problems, we propose a distributed data storage scheme employing blockchain and cetrificateless cryptography. Our scheme eliminates the traditional centralized servers by leveraging the blockchain miners who perform “transaction” verifications and records audit with the help of certificateless cryptography. We present a clear definition of the transactions in a non-cryptocurrency system and illustrate how the transactions are processed. To the best of our knowledge, this is the first work designing a secure and accountable IoT storage system using blockchain. Additionally, we extend our scheme to enable data trading and elaborate how data trading can be efficiently and effectively achieved.

Blockchain for Large-Scale Internet of Things Data Storage and Protection

In this paper, we propose new constructions for regular girth-8 quasi-cyclic low-density parity-check (QC-LDPC) codes based on circulant permutation matrices (CPM). The constructions assume symmetries in the structure of the parity-check matrix and employ a greedy exhaustive search algorithm to find the permutation shifts of the CPMs. As a result of symmetries, the new codes have a more compact representation compared with their counterparts. In majority of cases, also, they achieve the girth 8 at a shorter block length for the same degree distribution (code rate). Deterministic (explicit) constructions are also presented to expand the proposed parity-check matrices to larger block lengths and higher rates. The proposed long high-rate codes are often substantially shorter than regular girth-8 QC-LDPC codes of similar rate in the literature. Simulation results demonstrate that the proposed symmetric codes have competitive performance in comparison with similar existing QC-LDPC codes that lack symmetry.

Symmetrical Constructions for Regular Girth-8 QC-LDPC Codes

A method of operating a hub used in an internet of things (IoT) network system which includes a first controller and an IoT device is provided. The method includes: performing secure pairing with the first controller using a first communication, receiving first information related to the IoT device from the first controller paired with the hub, authenticating the first controller using the first information, and performing secure pairing with the IoT device using a second communication.

Method of sharing key between devices using physical access restriction

For any row weight L, several novel classes of (J = 5, L) and (J = 6, L) quasi-cyclic LDPC codes are deterministically constructed with girth eight. From these results, it is proved that (5, L) QC-LDPC codes with girth eight exist for any circulant permutation matrix (CPM) size P ≥ (2L + 3)(L - 1) + 1, and that girth-eight (6, L) QC-LDPC codes exist for any P ≥ 2(L+5)(L-1)+1. The two novel bounds remarkably improve the existing bounds of L^2(L-1) + 1 and (L^2+1)(L-1)+1, respectively. Moreover, for any column weight J and any row weight L, a construction for (J,L) QC-LDPC codes with girth eight is also proposed. This is the first deterministic and systematic construction which can generate girth-eight QC-LDPC codes with J ≥ 7.

Deterministic Girth-Eight QC-LDPC Codes with Large Column Weight

In this paper, the problem involving joint blind frame synchronization and encoder identification for binary low-density parity-check (LDPC) codes of binary phase-shift keyed (BPSK) signals is tackled. The unknown encoder and time-delay can be blindly estimated simultaneously using the average log-likelihood ratios (LLRs) of syndrome a posteriori probability (APP). A new two-stage search method with a search step of size q by exploiting the quasi-cyclic nature of the parity-check matrix is devised to reduce the complexity of the blind frame synchronization algorithm. Numerous Monte Carlo simulations are evaluated to demonstrate the effectiveness of the new joint blind frame-synchronization and encoder-identification scheme for multi-path situations.

Joint Blind Frame Synchronization and Encoder Identification for Low-Density Parity-Check Codes

Some explicit constructions for exponent matrices which correspond to Tanner graphs with girth at least eight are proposed. From these results, for any row weight of L>3, (3,L) quasi-cyclic LDPC codes with girth at least eight are constructed for any circulant permutation matrix (CPM) size P>L(L+mod(L,2))/2.

Several Explicit Constructions for (3,L) QC-LDPC Codes with Girth at Least Eight

The invention discloses a wireless body area network security access method. Two interaction modes, namely, the unicast mode and the multicast mode, are set; two launching modes are set, and in other words, a network coordinator launches hand shaking and sensor nodes launch hand shaking; thus, when a certain part is injured and the blood pressure suddenly rises or in other words, the measurement indexes of a certain or some sensor nodes exceed the corresponding index limitations, the corresponding sensor nodes actively launch the hand shaking process, the situations of patients are rapidly fed back to medical staff, and patients are helped in time. According to the method, dynamic negotiation of a user conversation key is achieved through enhanced four-step hand shaking, hand shaking information is reduced, all the information is encrypted, the unicast access mode and the multicast access mode are set, and the remote access problem is solved through a multi-hop method. The method has the advantages that the access efficiency of a large number of sensing nodes is high, security is high, and the energy consumption is low, and the method can be used for the access of the sensing nodes in a wireless body area network and the dynamic negotiation of the user conversation key.

Wireless body area network security access method

For any row weight L and any circulant permutation matrix size P > (L − 1)2 + b 0(L − 1) (b 0 = L − 2 + mod(L,2)), a class of (3,L) quasi-cyclic (QC) low-density parity-check (LDPC) codes is explicitly constructed with girth eight, based on the quadratic function f(x) = x 2 + bx and its derivative, where b is either of the two integers {b 0, − b 0 − 2(L − 2)}. Compared with a similar construction from the so-called difference sequence, the proposed construction is not only much more simple in concept, but also completely deterministic in the sense that no computer search or computing is required. Simulation results show that the new codes significantly outperform the girth-eight codes constructed by the earliest-sequence-based method.

Deterministic construction of girth-eight (3, L ) QC-LDPC codes from quadratic function

Most of the piggybacking designs can only effectively repair systematic nodes. In this letter, we propose a new piggybacking method for repairing parity nodes based on the existing piggybacking design. By elaborately designing piggyback functions and making full use of each parity node, the improved piggybacking design reduces the repair bandwidth of parity nodes while retaining the repair bandwidth of systematic nodes. Compared with the existing designs, the proposed method has lower complexity, fewer substripes and better comprehensive repair properties in large-scale distributed storage systems.

A New Piggybacking Design With Low-Repair Bandwidth and Complexity

Nonuniform quantisation of mid-variables such as the forward and backward recursion metrics for the MAP turbo code decoding algorithm is studied. It is shown that the performance of nonuniform mid-variable quantisation is much better than that of uniform quantisation.

Rong Sun

Papers

Several Explicit Constructions for (3,L) QC-LDPC Codes with Girth at Least Eight

Wireless body area network security access method

Deterministic construction of girth-eight (3, L ) QC-LDPC codes from quadratic function

A New Piggybacking Design With Low-Repair Bandwidth and Complexity

Nonuniform quantisation of mid-variables for decoding of turbo codes