E-healthcare assists medical specialists in remotely collecting patient health data and providing remote health diagnoses. The roles are distributed among the system's users, contrasted between admin to data entry within certain rules and policies. Role-based access control (RBAC) is a technique of advanced access control that restricts key operations of users (addition, deletion and modification) access based on a user's role within a healthcare system. This paper proposes a privacy-preserving using RBAC and smart multi-factor authentication for the healthcare system to overcome the limitation flaw in previous schemes such as security risk tolerance, scalability and dynamism. This work relies on low-complexity cryptographic hash functions and symmetric operations to authenticate users while using an asymmetric cryptosystem based on the Schnorr digital signature lightweight operation to authenticate the administrator to provide multi-factor authentication. The administrator represents the system's core, and any his information leak could attack the entire system and its components. The proposed scheme conducted two thorough formal security proofs for the proposed work based on informal analysis and the Scyther tool. Furthermore, comparisons with other schemes reveal that the proposed scheme provides greater security features, and resisting attacks than the others while also being efficient in computing and communication costs.

Authentication of vehicles and users, integrity of exchanged messages, and privacy preservation are essential features in VANETs. VANETs are used to collect information on road conditions, vehicle location and speed, and traffic congestion data. The open exchange of information within VANETs poses serious security threats. Furthermore, existing schemes have higher communication and computational costs, making them incompatible with resource-constrained VANET applications. This study proposes a multifactor authentication and privacy-preserving security scheme for VANETs based on blockchain and fog computing to meet all these requirements. The proposed scheme uses fingerprints and Quick Response (QR) codes as a multifactor to authenticate vehicle users and fog-cloud computing techniques to reduce the computational burden on RSUs and improve service quality and resilience. Additionally, the scheme synchronizes a consistent ledger across all RSUs using blockchain technology to store and distribute vehicle authentication statuses. Through a thorough comparison with relevant current protocols, the scheme shows a much-reduced computing expense and communication burden in situations with high vehicle density within a timeframe of 6.3846 ms and 544 bytes for communication costs. In addition, the proposed scheme demonstrates a successful balance between efficacy and complexity, protecting confidentiality, anonymous authentication, and ensuring integrity and conditional tracking. Formal and informal security analysis showed that the proposed scheme is more reliable, practical, and secure against many hostile attacks, such as modification attacks, 51% attacks, Sybil attacks, and MITM attacks.

Advances in cloud computing and Internet technologies have pushed more and more data owners to outsource their data to remote cloud servers to enjoy with huge data management services in an efficient cost. However, despite its technical advances, cloud computing introduces many new security challenges that need to be addressed well. This is because, data owners, under such new setting, loss the control over their sensitive data. To keep the confidentiality of their sensitive data, data owners usually outsource the encrypted format of their data to the untrusted cloud servers. Several approaches have been provided to enable searching the encrypted data. However, the majority of these approaches are limited to handle either a single keyword search or a Boolean search but not a multikeyword ranked search, a more efficient model to retrieve the top documents corresponding to the provided keywords. In this paper, we propose a secure multi-keyword ranked search scheme over the encrypted cloud data. Such scheme allows an authorized user to retrieve the most relevant documents in a descending order, while preserving the privacy of his search request and the contents of documents he retrieved. To do so, data owner builds his searchable index, and associates with each term document with a relevance score, which facilitates document ranking. The proposed scheme uses two distinct cloud servers, one for storing the secure index, while the other is used to store the encrypted document collection. Such new setting prevents leaking the search result, i.e. the document identifiers, to the adversary cloud servers. We have conducted several empirical analyses on a real dataset to demonstrate the performance of our proposed scheme.

Cloud security represents a main hindrance that causes to retard its widespread adoption. Authentication considers a significance element of security in cloud environment, aiming to verify a user's identity when a user wishes to request services from cloud. There are many authentication schemes that depend on username/password, but they are considered weak techniques of cloud authentication. A more secure scheme is the two-factor authentication that does not only verify the username/password pair, but also needs a second factor such as a token device, biometric. However, the feasibility of second-factor authentication is limited by the deployment complexity, high cost and the cloud security is compromised when the token is missing or purloined. Furthermore, these schemes are failed to resist well-known attacks such as replay attacks, reflection attacks. This paper proposes two-factor authentication scheme based on Schnorr digital signature and feature extraction from fingerprint to overcome above aforementioned issues. Security analysis and experimental results illustrate that our proposed scheme can withstand the common security attacks as well, and has a good performance of password authentication.

Internet of Things is a new generation of network service platform that allows everyday objects including small devices in sensor networks to be capable of connecting to the internet. Such an innovative technology can lead to positive changes in human life. An e-health service based on the Internet of Things has great potential. The popularity of intelligent mobile medical devices, wearable bio-medical sensor devices, cloud computing, and big data analysis have dramatically changed the usage pattern and business rule of e-health services based on the Internet of Things. The rapid development of e-health services based on the Internet of Things poses risks in security and privacy. In this study, we propose a new security scheme for an e-health service. This scheme allows both the local base station and hospital cloud server to authenticate each other, to secure the collection of health data. Our scheme uses the crypto hash function to check the integrity of authentication exchanges. In addition, it provides mutual authentication with anonymity and terminates with a session key agreement between each local base station and the hospital cloud server. To assess our scheme, we conduct performance and security analysis. Results show that our scheme is secure, lightweight, and resistant to different types of attacks.