Towards enhanced key management in multi-phase ZigBee network architecture

ZigBee is one of impartment wireless technologies now being widely deployed in wireless sensor networks (WSNs). However, ZigBee exhibits several security concerns especially insufficiently addressed key management mechanism. The security of WSNs has a direct reliance on secure and efficient key management. This leaves key management as a fundamental research topic in the field of WSNs security. Among the proposed key management schemes for WSNs security, the localized encryption and authentication protocol (LEAP) has been regarded as an efficient protocol over the last years. LEAP supports the establishment of four types of keys. The security of these keys is under the assumption that the initial deployment phase is secure and the initial key is erased from sensor nodes after the initialization phase. Whilst the initial key is used again for node addition after the initialization phase whereas the new node can be compromised before erasing the key. A time-based key management scheme rethought the security of LEAP. We show the deficiency of the time-based key management scheme and developed an enhanced key management scheme for multi-phase ZigBee architecture in this paper. We show the proposed comprehensive key management solution keeps forward and backward secrecy and suits the application requirements and constraints through analysis and simulation

A Comparative and Comprehensive Characterization of Polyphenols of Selected Fruits from the Rosaceae Family

The present research presents a comprehensive characterization of polyphenols from peach, pear, and plum using liquid chromatography coupled with electrospray ionization quadrupole-time-of-flight-mass spectrometry (LC-ESI-QTOF-MS/MS), followed by the determination of their antioxidant potential. Plums showed the highest total phenolic content (TPC; 0.62 mg GAE/g), while peaches showed the highest total flavonoid content (TFC; 0.29 mg QE/g), also corresponding to their high scavenging activities (i.e., DPPH, ABTS, FRAP, and TAC). In all three fruit samples, a total of 51 polyphenolic compounds were tentatively identified and were mainly characterized from hydroxybenzoic acids, hydroxycinnamic acids, hydroxyphenylpentanoic acids, flavanols, flavonols, and isoflavonoids subclasses. Twenty targeted phenolic compounds were quantified using high-performance liquid chromatography with photodiode array detection (HPLC-PDA). The plum cultivar showed the highest content of phenolic acids (chlorogenic acid, 11.86 mg/100 g), whereas peach samples showed the highest concentration of flavonoids (catechin, 7.31 mg/100 g), as compared to pear. Based on these findings, the present research contributes and complements the current characterization data of these fruits presented in the literature, as well as ensures and encourages the utilization of these fruits in different food, feed, and nutraceutical industries

[4 + 3] Cycloaddition of Phthalazinium Dicyanomethanides with Azoalkenes Formed in Situ: Synthesis of Triazepine Derivatives

[4 + 3] cycloaddition of phthalazinium dicyanomethanides with in situ formed azoalkenes was achieved, providing an access to various 1,2,4-triazepine derivatives in moderate to excellent yields

Phosphine-Catalyzed [4 + 2] Annulation of Allenoate with Sulfamate-Derived Cyclic Imines: A Reaction Mode Involving γ′-Carbon of α‑Substituted Allenoate

A phosphine-catalyzed [4 + 2] cycloaddition of cyclic α-substituted allenoates with sulfamate-derived cyclic imines has been reported. Using dibenzylphenylphosphine as the nucleophilic catalyst, the reaction worked efficiently to yield various fused multicyclic heterocyclic compounds in high yields with excellent diastereoselectivities. It undergoes a new reaction mode involving γ′-carbon of α-substituted allenoate