The health care ecosystem involves various interconnected stakeholders with different, and sometimes conflicting security and privacy needs. Sharing medical data, sometimes generated by remote medical devices, is a challenging task. Although several solutions exist in the literature covering functional requirements such as interoperability and scalability, as well as security & privacy requirements such as fine-grained access control and data privacy, balancing between them is not a trivial task as off-the-shelf solutions do not exist. On one hand, centralized cloud architectures provide scalability and interoperable access, but make strong trust assumptions. On the other, decentralized blockchain based solutions favor data privacy and independent trust management, but typically do not support dynamic changes of the underlying trust domains. To cover this gap, in this paper, we present a novel hierarchical multi expressive blockchain architecture. At the top layer, a proxy blockchain enables independently managed trust authorities to interoperate. End-users from different health care domains, such as hospitals or device manufacturers are able to access and securely exchange medical data, provided that a commonly agreed domain-wise access policy is enforced. At the bottom layer, one or more domain blockchains allow each domain (e.g. a hospital or device manufacturer) to enforce their policy and allow fine-grained access control with attribute-based encryption. This architecture is designed to provide the autonomous management of trusted medical data/devices and the transactions of mutually untrusted stakeholders, as well as an inherent forensics mechanism tailored for granular auditing. Smart contracts are used to enforce decentralized policies. Ciphertext-policy attribute based encryption (CP-ABE) is used to distribute the decryption process among end users and the system, as well as support an efficient credential revocation mechanism. We demonstrate the efficiency of the proposed architecture through a proof of concept implementation. Finally we analyse the major security and performance characteristics.

This paper examines two unlinkably anonymous, simple RFID identification protocols that require only the ability to evaluate hash functions and generate random values, and that are provably secure against Byzantine adversaries. The main contribution is a universally composable security model tuned for RFlD applications. By making specific setup, communication, and concurrency assumptions that are realistic in the RFID application setting, we arrive at a model that guarantees strong security and availability properties, while still permitting the design of practical RFID protocols. We show that two protocols are provably secure within the new security model. Our proofs do not employ random oracles - the protocols are shown to be secure in the standard model under the assumption of existence of pseudo-random function families

The National Strategy for Global Supply Chain Security published in 2012 by the White House identifies two primary goals for strengthening global supply chains: first, to promote the efficient and secure movement of goods, and second to foster a resilient supply chain. The Internet of Things (IoT), and in particular Radio Frequency Identification (RFID) technology, can be used to realize these goals. For product identification, tracking and real-time awareness, RFID tags are attached to goods. As tagged goods move along the supply chain from the suppliers to the manufacturers, and then on to the retailers until eventually they reach the customers, two major security challenges can be identified: (I) to protect the shipment of goods that are controlled by potentially untrusted carriers; and (II) to secure the transfer of ownership at each stage of the chain. For the former, grouping proofs in which the tags of the scanned goods generate a proof of “simulatenous” presence can be employed, while for the latter, ownership transfer protocols (OTP) are used. This paper describes enhanced security solutions for both challenges. We first extend earlier work on grouping proofs and group codes to capture resilient group scanning with untrusted readers; then, we describe a modified version of a recently published OTP based on channels with positive secrecy capacity adapted to be implemented on common RFID systems in the supply chain. The proposed solutions take into account the limitations of low cost tags employed in the supply chain, which are only required to generate pseudorandom numbers and compute one-way hash functions.