Multi-Factor Password-Authenticated Key Exchange via Pythia PRF Service

Multi-factor authentication(MFA)was proposed by Pointcheval et al.[Pointcheval and Zimmer(2008)]to improve the security of single-factor(and two-factor)authentication.As the backbone of multi-factor authentication,biometric data are widely observed.Especially,how to keep the privacy of biometric at the password database without impairing efficiency is still an open question.Using the vulnerability of encryption(or hash)algorithms,the attacker can still launch offline brute-force attacks on encrypted(or hashed)biometric data.To address the potential risk of biometric disclosure at the password database,in this paper,we propose a novel efficient and secure MFA key exchange(later denoted as MFAKE)protocol leveraging the Pythia PRF service and password-to-random(or PTR)protocol.Armed with the PTR protocol,a master password pwd can be translated by the user into independent pseudorandom passwords(or rwd)for each user account with the help of device(e.g.,smart phone).Meanwhile,using the Pythia PRF service,the password database can avoid leakage of the local user’s password and biometric data.This is the first paper to achieve the password and biometric harden service simultaneously using the PTR protocol and Pythia PRF.

Screening of Drought Resistance Identification Indexes for Rice(Oryza sativa L.) Cultivars in Ningxia

The morphological characters, physiological characters, yield traits and yield per plant of total 49 rice cultivars from Ningxia were investigated under conditions of water stress and non-water stress so as to determine the relationship between each trait and yield per plant under water stress and the relationship between each relative character and drought resistance coefficient under water stress and non-water stress. The correlation, grey correlation, stepwise regression and path analyses showed that the tiller number per plant, plant height, grain density, effective panicle number per plant and grain number per panicle, total 5 traits, were significantly correlated with the drought resistance of rice, and they could be used to identify the drought resistance of rice in Ningxia. In addition, the drought resistance of rice was graded qualitatively according to the subordinate function value of corresponding drought resistance coefficient. The results showed that among the 49 rice cultivars from Ningxia,6 rice cultivars were highly drought resistant, and 9 rice cultivars were moderately drought resistant, suggesting that the evaluation method was feasible and effective.

Blockchain Data Analysis from the Perspective of Complex Networks:Overview

Cryptocurrency based on blockchain technology has gradually become a choice for people to invest in,and several users have participated in the accumulation of massive transaction data.Complete transaction records in blockchains and the openness of data provide researchers with opportunities to mine and analyze data in blockchains.Network modeling and analysis of cryptocurrency transaction records are common methods in blockchain data analysis.The analysis of attribute graphs can provide insights into various economic indicators,illegal activities,and general Internet security,among others.Accordingly,this article aims to summarize and analyze the literature on cryptocurrency transaction data from the perspective of complex networks.To provide systematic guidance for researchers,we put forward a blockchain data analysis framework based on the introduction of the relevant background and reviewed the work from five aspects:blockchain data model,data acquisition on blockchains,existing analysis tools,available insights,and common analysis methods.For each aspect,we introduce the research problems,summarize the methods,and discuss the results and findings.Finally,we present future research points and several open questions in the study of cryptocurrency transaction networks.