A Ciphertext Policy Attributes-based Encryption Scheme with Policy Revocation

There are a lot of data exchanges among the parties by using cloud computing. So data protection is very important in cloud security environment. Especially, data protection is needed for all organization by security services against unauthorized accesses. There are many security mechanisms for data protection. Attributes-based Encryption (ABE) is a one-to-many encryption to encrypt and decrypt data based on user attributes in which the secret key of a user and the ciphertext are dependent upon attributes. Ciphertext policy attributes-based encryption (CP-ABE), an improvement of ABE schemes performs an access control of security mechanisms for cloud storage. In this paper, sensitive parts of personal health records (PHRs) are encrypted by ABE with the help of CP-ABE. Moreover, an attributes-based policy revocation case is considered as well as user revocation and it needs to generate a new secret key. In proposed policy revocation case, PHRs owner changes attributes policy to update available user lists. A trusted authority (TA) is used to issue secret keys as a third party. This paper emphasizes on key management and it also improves attributes policy management and user revocation. Proposed scheme provides a full control on data owner as much as he changes policy. It supports a flexible policy revocation in CP-ABE and it saves time consuming by comparing with traditional CP-ABE

Efficacy and safety of dihydroartemisinin-piperaquine for treatment of Plasmodium vivax malaria in endemic countries: meta-analysis of randomized controlled studies

Background: This study aimed to synthesize available evidence on the efficacy of dihydroartemisinin-piperaquine (DHP) in treating uncomplicated Plasmodium vivax malaria in people living in endemic countries. Methodology and Principal Findings: This is a meta-analysis of randomized controlled trials (RCT). We searched relevant studies in electronic databases up to May 2013. RCTs comparing efficacy of (DHP) with other artemisinin-based combination therapy (ACT), non-ACT or placebo were selected. The primary endpoint was efficacy expressed as PCR-corrected parasitological failure. Efficacy was pooled by hazard ratio (HR) and 95% CI, if studies reported time-to-event outcomes by the Kaplan-Meier method or data available for calculation of HR Nine RCTs with 14 datasets were included in the quantitative analysis. Overall, most of the studies were of high quality. Only a few studies compared with the same antimalarial drugs and reported the outcomes of the same follow-up duration, which created some difficulties in pooling of outcome data. We found the superiority of DHP over chloroquine (CQ) (at day > 42-63, HR:2.33, 95% CI:1.86-2.93, I: 0%) or artemether-lumefentrine (AL) (at day 42, HR:2.07, 95% CI:1.38-3.09, I: 39%). On the basis of GRADE criteria, further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. Discussion/Conclusion: Findings document that DHP is more efficacious than CQ and AL in treating uncomplicated P. vivax malaria. The better safety profile of DHP and the once-daily dosage improves adherence, and its fixed coformulation ensures that both drugs (dihydroartemisinin and piperaquine) are taken together. However, DHP is not active against the hypnozoite stage of P. vivax. DHP has the potential to become an alternative antimalarial drug for the treatment uncomplicated P. vivax malaria. This should be substantiated by future RCTs with other ACTs. Additional work is required to establish how best to combine this treatment with appropriate antirelapse therapy (primaquine or other drugs under development)