Fine-Grained and Fair Identity Authentication Scheme for Mobile Networks Based on Blockchain

With the popularity of the internet,users hope to better protect their privacy while obtaining network services.However,in the traditional centralized authentication scheme,identity information such as the user's private key is generated,stored,and managed by the network operator.Users can't control their identity information,which will lead to a great threat to the privacy of users.Based on redactable blockchain,we propose a fine-grained and fair identity authentication scheme for mobile networks.In our proposed scheme,the user's identity information is generated and controlled by the users.We first propose a notion of score chameleon hash(SCH),which can delete or update the information of illegal users so as to dynamically update the status of users and provide users with more fine-grained and fair services.We propose another notion of self-updating secret sharing(SUSS),which allows users to update the trapdoor and the corresponding hash key after redacting the blockchain without requiring trusted authority to redistribute the trapdoor.Experimental results show that,compared with the immutable blockchain Bitcoin,the redactable blockchain in our identity authentication scheme provides users with fine-grained and fair redacting functions,and can be adopted with a small additional overhead.

Application Status and Prospects of Biogas Fertilizer in Modern Agricultural Production

On the basis of introducing the nutrient composition and biogas fertilizer,the effects of biogas fertilizer on soil,crops and environment are summarized. Biogas fertilizer can improve soil structure,increase soil organic matter,available nutrient contents and enzyme activity,increase crop yield,quality and resistance,and relieve the non-point source pollution effectively. The harmlessness,application technology and risk are analyzed. Some suggestions are put forward to control the source pollution,strengthen the research of fermentation technology,define the standard of biogas fertilizer,and carry out large and medium-sized biogas engineering.

π-Armendariz rings relative to a monoid

Let M be a monoid. A ring R is called M-π-Armendariz if whenever a = a1g1＋ a292 ＋ …＋angn, β= b1h1 ＋ b2h2 ＋ …＋ bmhm ∈ R[M] satisfy αβ ∈ nil（R[M]）, then aibj ∈ nil（R） for all i, j. A ring R is called weakly 2-primal if the set of nilpotent elements in R coincides with its Levitzki radical. In this paper, we consider some extensions of M-Tr-Armendariz rings and further investigate their properties under the condition that R is weakly 2-primal. We prove that if R is an M-π-Armendariz ring then nil（R[M]） = nil（R）[M]. Moreover, we study the relationship between the weak zip-property （resp., weak APP-property, nilpotent p.p.-property, weak associated prime property） of a ring R and that of the monoid ring RIM] in case R is M-π-Armendariz.

The Knowledge on HCV:From the Discovery to the Elimination

From being described as“non-A,non-B”hepatitis in 1975 and being identified in 1989,to the emergence of direct-acting antiviral drugs(DAAs),knowledge on hepatitis C virus(HCV)has achieved a qualitative leap in recent decades.Although more than 95%of HCV patients can be cured by DAAs,the high detection rate,high treatment cost,and relative high recurrence rate for some subtypes(eg,type 3b)make it still a public health problem worldwide.Due to the widespread availability of DAAs,vaccine research has received relatively little attention.The purpose of this review is to look back to the discovery of the HCV,its life cycle,innate and adaptive immune responses,and the evolution of treatment options for HCV.