Electronic health record (EHR) systems are extremely useful for managing patients' data and are widely disseminated in the health sector. The main problem with these systems is how to maintain the privacy of sensitive patient information. Due to not fully protecting the records from unauthorised users, EHR systems fail to provide privacy for protected health information. Weak security measures also allow authorised users to exceed their specific privileges to access medical records. Thus, some of the systems are not a trustworthy source and are undesirable for patients and healthcare providers. Therefore, an authorisation system that provides privacy when accessing patients' data is required to address these security issues. Specifically, security and privacy precautions should be raised for specific categories of users, doctor advisors, physician researchers, emergency doctors, and patients' relatives. Presently, these users can break into the electronic systems and even violate patients' privacy because of the privileges granted to them or the inadequate security and privacy mechanisms of these systems. To address the security and privacy problems associated with specific users, we develop the Pseudonymization and Anonymization with the XACML (PAX) modular system, which depends on client and server applications. It provides a security solution to the privacy issues and the problem of safe-access decisions for patients' data in the EHR. The~results of theoretical and experimental security analysis prove that PAX provides security features in preserving the privacy of healthcare users and is safe against known attacks.

Healthcare institutions require advanced technology to collect patients’ data accurately and continuously. The tradition technologies still suffer from two problems: performance and security efficiency. The existing research has serious drawbacks when using public-key mechanisms such as digital signature algorithms. In this paper, we propose Reliable and Efficient Integrity Scheme for Data Collection in HWSN (REISCH) to alleviate these problems by using secure and lightweight signature algorithms. The results of the performance analysis indicate that our scheme provides high efficiency in data integration between sensors and server (saves more than 24% of alive sensors compared to traditional algorithms). Additionally, we use Automated Validation of Internet Security Protocols and Applications (AVISPA) to validate the security procedures in our scheme. Security analysis results confirm that REISCH is safe against some well-known attacks.

Providing a mechanism to authenticate users in healthcare applications is an essential security requirement to prevent both external and internal attackers from penetrating patients' identities and revealing their health data. Many schemes have been developed to provide authentication mechanisms to ensure that only legitimate users are authorized to connect, but these schemes still suffer from vulnerable security. Various attacks expose patients' data for malicious tampering or destruction. Transferring healthrelated data and information between users and the health centre makes them exposed to penetration by adversaries as they may move through an insecure channel. In addition, previous mechanisms have suffered from the poor protection of users' authentication information. To ensure the protection of patients' information and data, we propose a scheme that authenticates users based on the information of both the device and the legitimate user. In this paper, we propose a Robust Authentication Model for Healthcare Users (RAMHU) that provides mutual authentication between server and clients. This model utilizes an Elliptic Curve Integrated Encryption Scheme (ECIES) and PHOTON to achieve strong security and a good overall performance. RAMHU relies on multi pseudonyms, physical address, and one-time password mechanisms to authenticate legitimate users. Moreover, extensive informal and formal security analysis with the automated validation of Internet security protocols and applications (AVISPA) tool demonstrates that our model offers a high level of security in repelling a wide variety of possible attacks.