Cloud Computing Using Attribute Based Encryption

Published Date: 02 Nov 2017

Personal health record (PHR) is an emerging patient-centric model of health information exchange, which is often outsourced to be stored at a third party, such as cloud providers. However, there have been wide privacy concerns as personal health information could be exposed to those third party servers and to unauthorized parties. To assure the patients’ control over access to their own PHRs, it is a promising method to encrypt the PHRs before outsourcing. Yet, issues such as risks of privacy exposure, scalability in key management, flexible access and efficient user revocation, have remained the most important challenges toward achieving fine-grained, cryptographically enforced data access control. In this paper, we propose a novel patient-centric framework and a suite of mechanisms for data access control to PHRs stored in semi-trusted servers. To achieve fine-grained and scalable data access control for PHRs, we leverage attribute based encryption (ABE) techniques to encrypt each patient’s PHR file. Different from previous works in secure data outsourcing, we focus on the multiple data owner scenario, and divide the users in the PHR system into multiple security domains that greatly reduces the key management complexity for owners and users. A high degree of patient privacy is guaranteed simultaneously by exploiting multi-authority ABE. Our scheme also enables dynamic modification of access policies or file attributes, supports efficient on-demand user/attribute revocation and break-glass access under emergency scenarios. Extensive analytical and experimental results are presented which show the security, scalability and efficiency of our proposed scheme.

I. INTRODUCTION

Personal health record (PHR) is an emerging patient-centric model of health information exchange, which is often outsourced to be stored at a third party, such as cloud providers. However, there have been wide privacy concerns as personal health information could be exposed to those third party servers and to unauthorized parties. To assure the patients’ control over access to their own PHRs, it is a promising method to encrypt the PHRs before outsourcing. Yet, issues such as risks of privacy exposure, scalability in key management, flexible access and efficient user revocation, have remained the most important challenges toward achieving fine-grained, cryptographically enforced data access control. In this paper, we propose a novel patient-centric framework and a suite of mechanisms for data access control to PHRs stored in semi-trusted servers. To achieve fine-grained and scalable data access control for PHRs, we leverage attribute based encryption (ABE) techniques to encrypt each patient’s PHR file. Different from previous works in secure data outsourcing, we focus on the multiple data owner scenario, and divide the users in the PHR system into multiple security domains that greatly reduces the key management complexity for owners and users. A high degree of patient privacy is guaranteed simultaneously by exploiting multi-authority ABE. Our scheme also enables dynamic modification of access policies or file attributes, supports efficient on-demand user/attribute revocation and break-glass access under emergency scenarios. Extensive analytical and experimental results are presented which show the security, scalability and efficiency of our proposed scheme

II.EXISTING SYSTEM

Due to the high cost of building and maintaining specialized data centers, many PHR services are outsourced to or provided by third-party service providers. There are many security and privacy risks which could impede its wide adoption. The main concern is about the patients could not have full control over her sensitive personal health information (PHI), especially when they are stored on a third-party server. Due to the high value of the sensitive personal health information (PHI), the third-party storage servers are often the targets of various malicious behaviors which may lead to exposure of the PHI. As a famous incident, a Department of Veterans Affairs database containing sensitive PHI of 26.5 million military veterans, including their social security numbers and health problems was stolen by an employee who took the data home without authorization.

III.PROPOSED SYSTEM

In order to protect the personal health data stored on a semi-trusted server, we adopt attribute-based encryption (ABE) as the main encryption primitive. PHR owner herself should decide how to encrypt her files and to allow which set of users to obtain access to each file .A PHR file should only be available to the users who are given the corresponding decryption key, while remain confidential to the rest of users. Furthermore, the patient shall always retain the right to not only grant, but also revoke access privileges when they feel it is necessary.

A secret key is generated for every user in public domain and a common secret key is generated for personnel domain Different from the single data owner scenario considered in most of the existing works, in a PHR system, there are multiple owners who may encrypt according to their own ways, possibly using different sets of cryptographic keys. Letting each user obtain keys from every owner who’s PHR she wants to read would limit the accessibility since patients are not always online.

IV. SYSTEM DESIGN

Fig 4.1 System Design

V MODULES DESCRIPTION

1. PROFILE DEVELOPMENT

The profile development is the Central Authority of Scalable and Secure Sharing of Personal Health Records. The Core Development is responsible for Register PHR owners and PHR users and theirs Login processes. It is also responsible for Profile maintenance of PHR owners and PHR users. Register :This module responsible for registering and removing accounts of PHR owners and PHR users in our framework .Login :This module responsible for enable login and logout processes for PHR owners and PHR users accordingly .Profile Maintenance :In this module the PHR owners, Personal users, Public users, Attribute Authorities can maintain their profile. All users can modify their profile such as edit, show or remove their profiles.

2 .PHR MANIPULATION

In this module the PHR owner should decide how to encrypt her files and to allow which set of users to obtain access to each file. We refer to the two categories of users as personal and professional users, respectively. In order to protect the personal health data stored on a semi-trusted server, we adopt attribute-based encryption (ABE) as the main encryption primitive. Using ABE, access policies are expressed based on the attributes of users or data, which enables a patient to selectively share her PHR among a set of users by encrypting the file under a set of attributes, without the need to know a complete list of users .Create PHR:PHR owners can able to create theirs PHR file and can set its properties such as type, category with their own desire. They can encrypt any number of records and store it in our framework. Maintain PHR :In this phase the PHR owners can maintain their records. They can able to update records with latest changes. They can able to produce keys for decrypt records and distribute them for personal domain users .Set access privileges:

They can set access privileges to their records and set permissions for accessing records. They can reset access privileges to their records and can maintain record history. Using ABE, access policies are expressed based on the attributes of users or data, which enables a patient to selectively share her PHR among a set of users by encrypting the file under a set of attributes, without the need to know a complete list of users. They can able for dynamic modification of access policies.

3.MA IMPLEMENTATION

In the public domain, we use multi-authority ABE (MA-ABE) to improve the security and avoid key escrow problem. Each attribute authority (AA) in it governs a disjoint subset of user role attributes, while none of them alone is able to control the security of the whole system. We propose mechanisms for key distribution and encryption so that PHR owners can specify personalized fine-grained role-based access policies during file encryption .Request and obtain keys :Letting each user obtain keys from every owner who’s PHR she wants to read would limit the accessibility since patients are not always online. The MA s such as the American Medical Association (AMA), the American Board of Medical Specialties (ABMS), and the American Hospital Association (AHA) and Insurance Domains and Medical Companies are need to request the PHR for obtaining decryption keys for read PHR file. Provide keys to public users :Public users have to obtain their secret key from multiple AAs by request them. The MA check the user’s credential and may provide keys to them. Using the keys the user can access PHR file.

4.ED IMPLEMENTATION

The PHR owner shall always retain the right to not only grant, but also revoke access privileges when they feel it is necessary. The Emergency Department(ED) responsible for provide break-glass key, for access PHER file due to the emergency. The emergency key set by the PHR owner while encrypting the PHR file .Set Break-Glass access: When an emergency happens, the regular access policies may no longer be applicable. To handle this situation, break-glass access is needed to access the victim’s PHR. In our framework, each owner’s PHR’s access right is also delegated to an emergency department. To prevent from abuse of break-glass option, the emergency staff needs to contact the ED to verify her identity and the emergency situation, and obtain temporary read keys .Revoke privileges :After the emergency is over, the PHR owner can revoke the emergent access via the ED and the new break-glass key will be created.

V.CONCLUSION

A secret key is generated for every user in public domain and a common secret key is generated for personnel domain. Different from the single data owner scenario considered in most of the existing works, in a PHR system, there are multiple owners who may encrypt according to their own ways, possibly using different sets of cryptographic keys. Attribute authority will maintain the key management.