The Internet of Things (IoT) network is rapidly expanding due to sudden technological advancements, which enable objects to become intelligent and contribute to the network. Before permitting a newly added IoT device to communicate with the network, it is essential to provide access and authenticate the device’s legitimacy by ensuring that it has not been tampered. Recently, blockchain technology has been integrated into Attribute Based Access Control (ABAC) protocols to supply a more robust security mechanism for access control in IoT. The IoT and blockchain-based ABAC serve as the foundation of this survey, offering a comprehensive introduction to both topics. Additionally, several security concerns and vulnerabilities associated with Blockchain Envisioned ABAC (BE-ABAC) are presented. A Comparison with related surveys has also been made. Besides, we also present a comparative analysis based on evaluation based on Distance from Average Solution (EDAS) to rank the best schemes among the suggested BE-ABAC schemes. In conclusion, we discuss some open research challenges in an IoT network that uses blockchain to manage access control.

With the popularization and growing utilization of electronic health records (EHRs) coupled with the advancements in cloud computing, healthcare providers are interested in storing EHRs in third-party, semi-trusted cloud platforms. Given the collaborative nature of modern e-health environments, integrating access delegation is of paramount importance to strengthen the flexibility of the sharing of health information. However, access delegation has to be enforced in a controlled manner so that it will not jeopardize the security of the system. For such applications, attribute based encryption (ABE) mechanisms are quite useful given the fact that ABE facilitates an efficient way of enforcing secure, fine-grained access control over encrypted data. However, incorporating delegatability with ABE mechanisms is tricky, and the existing schemes lack the control over the process of delegation of encrypted data. As a solution, we propose a novel ABE based access control scheme which can enforce multi-level, controlled access delegation and demonstrated how it could be deployed in an e-health environment to securely share outsourced EHRs of patients. Furthermore, we have shown that the proposed scheme is secure against chosen plaintext attacks as well as attacks mounted via attribute collusion.

We propose an efficient anonymous, attribute-based credential scheme capable of provisioning multi-level credential delegations. It is integrated with a mechanism to revoke the anonymity of credentials for resolving access disputes and making users accountable for their actions. The proposed scheme has a lower end-user computational complexity in comparison to existing credential schemes with delegatability and has a comparable level of performance with the credential standards of U-Prove and Idemix. Furthermore, we demonstrate how the proposed scheme can be applied to a collaborative e-health environment to provide its users with the necessary anonymous access with delegation capabilities.

Personal health records (PHR) are an emerging health information exchange model, which facilitates PHR owners to efficiently manage their health data. Typically, PHRs are outsourced and stored in third-party cloud platforms. Although, outsourcing private health data to third-party platforms is an appealing solution for PHR owners, it may lead to significant privacy concerns, because there is a higher risk of leaking private data to unauthorized parties. As a way of ensuring PHR owners' control of their outsourced PHR data, attribute based encryption (ABE) mechanisms have been considered due to the fact that such schemes facilitate a mechanism of sharing encrypted data among a set of intended recipients. However, such existing PHR solutions suffer from inflexibility and scalability issues due to the limitations associated with the adopted ABE mechanisms. To address these issues, we propose a distributed multi-authority ABE scheme and thereby we show how a patient-centric, attribute based PHR sharing scheme which can provide flexible access for both professional users such as doctors as well as personal users such as family and friends is realized. We have shown that the proposed scheme supports on-demand user revocation as well as secure under standard security assumptions. In addition, the simulation results provide evidence for the fact that our scheme can function efficiently in practice. Furthermore, we have shown that the proposed scheme can cater the access requirements associated with distributed multiuser PHR sharing environments as well as more realistic and scalable compared with similar existing PHR sharing schemes.

Electronic health records (EHRs) play a vital role in modern health industry, allowing the possibility of flexible sharing of health information in the quest of provisioning advanced and efficient healthcare services for the users. Although sharing of EHRs has significant benefits, given that such records contain lot of sensitive information, secure sharing of EHRs is of paramount importance. Thus, there is a need for the realization of sophisticated access control mechanisms for secure sharing of EHRs, which has attracted significant interest from the research community. The most prominent access control schemes for sharing of EHRs found in literature are role based and such solutions have the drawback of requiring the users to be registered in the system. Therefore, we propose a secure attribute based EHR sharing scheme using selective disclosure of attributes, which can meet the security requirements of EHRs. The proposed model is policy based and the access decisions are made based on the possibility of a user for being able to provide a proof that the user possesses a set of attributes that satisfies the access policy referenced to the access requested resource. Furthermore, the proposed model is capable of granting access for registered users in the system as well as unregistered but legitimate users, paving the way towards realizing a secure and flexible EHR sharing scheme.

Scyther [1] is designed to check the security and vulnerabilities of security protocols. In this paper, we use Scyther to analyze two discrete logarithm problem (DLP) based group authentication protocols proposed in [2]. These two protocols are claimed to satisfy several security requirements, but only part of them have been checked because of the properties and limitations of Scyther. Some positive results have been gained and show that the protocols provide mutual authentication and implicit key authentication and are secure against impersonation attack. An important innovation in this paper is that we have extended the expressing ability of Scyther by giving some reasonable assumption during the analysis and security checking.

This paper describes how location-aware role-based access control RBAC can be implemented on top of the Geospatial eXtensible Access Control Markup Language GeoXACML. It furthermore sketches how spatial separation of duty constraints both static and dynamic can be implemented using GeoXACML on top of the XACML RBAC profile. The solution uses physical addressing of geographical locations, which facilitates easy deployment of authorisation profiles to the mobile device. Location-aware RBAC can be used to implement location-dependent access control and also other security enhancing solutions on mobile devices, such as location-dependent device locking, firewall, intrusion prevention or payment anti-fraud systems. The system has been implemented and tested, both to verify the server capacity and also the client capacity running on a mobile device. Copyright © 2013 John Wiley & Sons, Ltd.

Unattended Wireless Sensor Networks (UWSNs) are characterized by long periods of disconnected operation and fixed or irregular intervals between sink visits. The absence of an online trusted third party implies that existing WSN trust management schemes are not applicable to UWSNs. In this paper, we propose a trust management scheme for UWSNs to provide efficient and robust trust data storage and trust generation. For trust data storage, we employ a geographic hash table to identify storage nodes and to significantly decrease storage cost. We use subjective logic based consensus techniques to mitigate trust fluctuations caused by environmental factors. We exploit a set of trust similarity functions to detect trust outliers and to sustain trust pollution attacks. We demonstrate, through extensive analyses and simulations, that the proposed scheme is efficient, robust and scalable.

This paper proposes an architecture and a methodology for privacy handling in Critical Information Infrastructures. Privacy is in this respect considered as both the risk of revealing person-sensitive information, for example from critical infrastructures in health institutions, but also to identify and avoid leakage of confidential information from the critical information infrastructures themselves. The architecture integrates privacy enhancing technologies into an enterprise service bus, which allows for policy-controlled authorisation, anonymisation and encryption of information in XML elements or attributes in messages on the service bus. The proposed methodology can be used to identify, quantify and reduce leakages of private or confidential information. It also suggests privacy enforcement mechanisms to increase the resilience against sensitive information leakages caused by cyber attacks.

Unattended Wireless Sensor Networks (UWSNs) are characterized by long periods of disconnected operation and fixed or irregular intervals between visits by the sink. The absence of an online trusted third party, i.e., an on-site sink, makes existing trust management schemes used in legacy wireless sensor networks not applicable to UWSNs directly. In this paper, we propose a trust management scheme for UWSNs to provide efficient, robust and scalable trust data storage. For trust data storage, we employ geographic hash table to efficiently identify data storage nodes and to significantly reduce storage cost. We demonstrate, through detailed analyses and extensive simulations, that the proposed scheme is efficient, robust, and scalable.

Body Area Network (BAN) consists of various types of small physiological sensors, transmission modules and low computational components and can thus form an E-health solution for continuous all-day and any-place health monitoring. To protect confidentiality of collected data, a shared group key is usually deployed in a BAN, and consequently a secure communication group is generated. In this paper, we propose a bi-directional security and collusion resilience key management scheme for BAN, referred to as FoSBaS. Detailed analysis shows that the scheme can provide both forward security and backward security and resist against collusion attacks. Furthermore, the FoSBaS is implemented on a Sun SPOT based sensor network testbed to evaluate its performance. Experimental results show that a group key can be updated within 102.13 ms with 60.22 mJ energy consumption on a 12 node BAN with 28 bits pairwise key.

Q&A social media have gained a lot of attention during the recent years. People rely on these sites to obtain information due to a number of advantages they offer as compared to conventional sources of knowledge. However, for the same question one may find highly contradicting answers, causing a

In this paper we propose a decentralized privacy-preserving scheme for mobile ad hoc networks (MANETs), where nodes establish security associations. In order to achieve privacy and security, we use homomorphic encryption and polynomial intersection so as to find the common friends of two nodes. Through our experimental results we verify the correctness of our scheme given the limitations of MANETs.

How to discover a captured node and to resist node capture attack is a challenging task in Wireless Sensor Networks (WSNs). In this paper, we propose a node capture resistance and key refreshing scheme for mobile WSNs which is based on the Chinese remainder theorem. The scheme is able of providing forward secrecy, backward secrecy and collusion resistance for diminishing the effects of capture attacks. By implementing our scheme on a Sun SPOT based sensor network testbed, we demonstrate that the time for updating a new group key varies from 56 ms to 546 ms and the energy consumption is limited to 16.5 - 225 mJ, depending on the length of secret keys and the number of sensors in a group.

In this paper, we present the novel concept of fractional public keys and an efficient zero-round multi-party Diffie-Hellman key agreement scheme that is based on fractional public keys. Shared group keys are computed highly efficiently by using the fractional public keys of multiple participants as exponents. The scheme provides therefore an efficient and elegant way of multi-party key agreement without key establishment data transmissions. The presented cryptographic scheme is collusion resistant to any number of users.

Unattended Wireless Sensor Networks (UWSNs) operated in hostile environments face a risk on data security due to the absence of real-time communication between sensors and sinks, which imposes sensors to accumulate data till the next visit of a mobile sink to off-load the data. Thus, how to ensure forward secrecy, backward secrecy and reliability of the accumulated data is a great challenge. For example, if a sensor is compromised, pre-compromise data accumulated in the sensor is exposed to access. In addition, by holding key secrecy of the compromised sensor, attackers also can learn post-compromise data in the sensor. Furthermore, in practical UWSNs, once sensors stop working for accidents due to node crash or battery depletion, all the data accumulated will be lost. To address the challenges, we propose a secure and reliable data distribution scheme in this paper. Detailed analysis shows that our scheme can provide forward secrecy, probabilistic backward secrecy and data reliability. To further improve probabilistic backward secrecy and data reliability, a constrained optimization data distribution scheme is proposed. Detailed analysis and simulation results show the superiority of the proposed scheme in comparison with several previous approaches developed for UWSNs.

It is important to analyse the privacy impact of Intrusion Detection System (IDS) rules, in order to understand and quantify the privacy-invasiveness of network monitoring services. The objective in this paper is to classify Snort rules according to the risk of privacy violations in the form of leaking sensitive or confidential material. The classification is based on a ruleset that formerly has been manually categorised according to our PRIvacy LEakage (PRILE) methodology. Such information can be useful both for privacy impact assessments and automated tests for detecting privacy violations. Information about potentially privacy violating rules can subsequently be used to tune the IDS rule sets, with the objective to minimise the expected amount of data privacy violations during normal operation. The paper suggests some classification tasks that can be useful both to improve the PRILE methodology and for privacy violation evaluation tools. Finally, two selected classification tasks are analysed by using a Nai¿ve Bayes classifier.

Today, Peer-to-Peer SIP based communication systems have attracted much attention from both academia and industry. The decentralized nature of P2P might provide the distributed peer-to-peer communication system without help of the traditional SIP server. However, it comes to the cost of reduced manageability and therefore causes security problems, e.g. distrust, privacy leaks, unpredictable availability, etc. In this paper, we investigate on P2PSIP security issues and propose a proxy-based system architecture that improves security during P2PSIP session initiation. The main issues considered in this architecture include Source inter-working, Encryption & Decryption, Policy Management, Destination inter-working, etc. We also implement a prototype with 16 Chord Secure Proxys (CSPs) and 496 P2PSIP peers. After that we analyze this system architecture in several aspects: number of hops and delay, trust upgrading, and the protection of security breaches (e.g. malicious or compromised intermediate peer). We take Chord as the P2PSIP overlay as example. However, this system architecture is independent of Chord overlay and could be extended to the other DHT (Distributed Hash Table) technologies.

Electronic patient records (EPR) may contain highly confidential and sensitive medical data, and it is therefore essential that such information is properly protected. Medical teams that are providing care to a patient has a legitimate need to access the medical data of the concerning patient, and this could be a valid criteria for medical professionals to obtain access to such data. Moreover, since teams consist of more than one individual, the consent or agreement among a number of the members of a medical team could by itself be a proper basis for trust and therefore a legitimate basis for medical teams to acquire access to medical data. In this paper, we present three closely related cryptographic protocols for secure team-based EPR access acquisition where the crypto graphically verifiable mutual consent from some minimum number of participants of a medical team is the granting criteria for the team to acquire EPR access. The schemes are based on threshold cryptography and are moreover broadcast-oriented, and are thus well-suited for wireless networks. All schemes do also provide secure transfer of medical data.

In this paper, we present three related and efficient cryptographic schemes for secure communication for hierarchically composed user groups. In such a group, each user is associated with a hierarchical level, so that the group members are divided into two or more hierarchical security classes. Most existing hierarchical cryptographic schemes provide hierarchical deduction of hierarchically arranged predefined keys. In contrast, the first scheme provides secure establishment of hierarchically ordered session keys. Since it prohibits long-term key deduction for underlying (and overlying) classes, such keys do not need to be updated session-wise. An essential security property is that the users can only obtain hierarchical session keys for their own and underlying levels, while it is prevented that a user can obtain hierarchical session keys of overlying levels.This scheme is extended to a hierarchical public key cryptosystem based on the ElGamal cryptosystem, and furthermore to an ElGamal-based threshold decryption scheme. Due to the threshold security requirement, at least t arbitrary group members are required to carry out decryption. The threshold scheme requires only one round of broadcasting in the decryption phase, and is thuswell-suitable for wireless networks.

A common property of practically all multi-party key agreement protocols is that they are non-hierarchical, i.e., they do not support user hierarchies. However, in real life, it is likely that members of groups and organizations differ in ranking according to their job positions so that people of higher rankings are privileged the same and higher privileged information than people of lower rankings. Hierarchical access control schemes address this issue, but they assume rather fixed scenarios based on centralized key distribution with predefined root keys and key parameters set by a trusted center. In this paper, we propose a decentralized efficient hierarchical multi-party key agreement protocol well-suited for ad-hoc wireless networks that ensures secure user hierarchies.

In cellular systems the issue of home control is an important one. With the subscriber being capable of roaming onto a large set of more-or-less trusted access networks, it has become important to strengthen the home network control. In this paper we propose a spatial mechanism directly incorporated in the authentication mechanism to improve on the degree of control a home network has for a roaming subscriber.