A Key Pre-Distribution Scheme Based on µ-PBIBD for Enhancing Resilience in Wireless Sensor Networks

Many key pre-distribution (KPD) schemes based on combinatorial design were proposed for secure communication of wireless sensor networks (WSNs). Due to complexity of constructing the combinatorial design, it is infeasible to generate key rings using the corresponding combinatorial design in large scale deployment of WSNs. In this paper, we present a definition of new combinatorial design, termed “µ-partially balanced incomplete block design (µ-PBIBD)”, which is a refinement of partially balanced incomplete block design (PBIBD), and then describe a 2-D construction of µ-PBIBD which is mapped to KPD in WSNs. Our approach is of simple construction which provides a strong key connectivity and a poor network resilience. To improve the network resilience of KPD based on 2-D µ-PBIBD, we propose a KPD scheme based on 3-D Ex-µ-PBIBD which is a construction of µ-PBIBD from 2-D space to 3-D space. Ex-µ-PBIBD KPD scheme improves network scalability and resilience while has better key connectivity. Theoretical analysis and comparison with the related schemes show that key pre-distribution scheme based on Ex-µ-PBIBD provides high network resilience and better key scalability, while it achieves a trade-off between network resilience and network connectivity

Online/Offline MA-CP-ABE with Cryptographic Reverse Firewalls for IoT

Devices in the Internet of Things (IoT) usually use cloud storage and cloud computing to save storage and computing cost. Therefore, the efficient realization of one-to-many communication of data on the premise of ensuring the security of cloud storage data is a challenge. Ciphertext-Policy Attribute-Based Encryption (CP-ABE) can not only protect the security of data in the cloud and achieve one-to-many communication but also achieve fine-grained access control for data. However, the single-authority CP-ABE faces the crisis of single point of failure. In order to improve security, the Multi-Authority CP-ABE (MA-CP-ABE) is adopted. Although there are provably-secure MA-CP-ABE schemes, Edward Snowden’s research shows that provably-secure cryptographic schemes are vulnerable to backdoor attacks, resulting in secret disclosure, and thus threatening security. In addition, ABE requires huge computational overhead in key generation, encryption and decryption, which increase with the increase in the number of attributes and the complexity of the access structure, and there are a large number of resource-constrained devices in the IoT. To mitigate this issue, we construct the Online/Offline MA-CP-ABE with Cryptographic Reverse Firewalls (OO-MA-CP-ABE-CRFs) scheme. This scheme not only uses Cryptographic Reverse Firewall (CRF) to resist backdoor attacks but also uses online/offline key generation, online/offline encryption and outsourcing encryption technology to optimize the efficiency of the MA-CP-ABE scheme with reverse firewall, reducing the storage and computing cost of users. Finally, the security of the OO-MA-CP-ABE-CRFs scheme is proved, and the experimental results indicate that the scheme is efficient and practical

Safety and immunogenicity of a quadrivalent, inactivated, split-virion influenza vaccine (IIV4-W) in healthy people aged 3-60 years: a phase III randomized clinical noninferiority trial

Background A quadrivalent split influenza vaccine IIV4-W against both influenza A and B viruses is urgently needed. Methods To evaluate the safety and immunogenicity of IIV4-W in people aged 3–60 years, 2400 participants recruited in a double-blind phase III trial and were randomly assigned to the IIV4-W, TIV1 and TIV2 groups. The immunogenicity indicators were measured at 28 days postvaccination and for 180 days for safety follow-up. Results Adverse events (AEs) occurred in 162 (20.28%), 116 (14.55%) and 123 (15.41%) participants in the IIV4-W, TIV1 and TIV2 groups, respectively. All these AEs were mild and self-limiting, and no serious AEs related to the vaccines were observed. IIV4-W elicited a non-inferior immune response for matched strains (the lower limit of 95% CI for GMT ratio >0.67, for SCR and SPR difference >-10%) and superior immune response for the additional B strains (the lower limit of 95% CI for GMT ratio >1.5, for SCR difference >10%) versus TIVs. The lower limit of the 95% confidence interval of the GMT increase fold, the seroconversion rate and the seroprotection rate exceeded 2.5, 40% and 70% for the four strains in IIV4-W respectively. Conclusions IIV4-W was noninferior to the TIV-matched strains and was superior to the additional B strain. IIV4-W was safe in the participants and elicited high antibody titers