It is widely believed that hyper elliptic curve cryptosystems (HECCs) are not attractive for wireless sensor network because of their complexity compared with systems based on lower genera, especially elliptic curves. Our contribution shows that for low cost security applications HECs cryptosystems can outperform elliptic curve cryptosystems. The aim of this paper is to propose a discrete logarithm problem-based lightweight secure communication system using HEC. We propose this for different genus curves over varied prime fields performing a full scale study of their adaptability to various types of constrained networks. Also, we propose to evaluate the performance of the protocol for computational times with respect to different genus for main operations like Jacobian, Divisor identifications, key generation, signature generation/verification, message encryption, and decryption by changing the size of the field. A formal security model was established based on the hardness of HEC-Decision Diffie-Hellman (HEC-DDH). Finally, a comparative analysis with ECC-based cryptosystems was made, and satisfactory results were obtained. KEYWORDSDiffie-Hellman, elliptic curve, genus, hyper elliptic curve, Jacobian, wireless sensor networks | INTRODUCTIONIn modern world, most of the wireless systems require resource constrained devices such as RFID tags, sensors, smart cards, small processors, PDA's, and smart phones. These devices play a major role in providing security for satellite communication, internet security, e-banking, e-commerce, Internet Of Things (IOT) applications, and embedded systems. Implementing security for wireless communication system using these devices is the most challenging problem. Many cryptographic algorithms were developed to accomplish their requirements for secure data communication in wireless systems. These algorithms have many limitations, which include increased power consumption, communication, and computational complexity with increased processing time. Thus, an efficient cryptographic algorithm that overcomes these limitations is the need of the hour.Public key cryptography (PKC) 1 offers a solution to the above limitations by using 2 different keys known as the public and private keys. The secret (private) key is chosen by the user and is well known only to him. The public key is computed from the private key by using a reversible mathematical process and is made open to all. Both the keys are interoperable on each other and are used for the decryption and encryption processes. As the private key is never revealed, PKC is highly secured unlike symmetric key cryptography. Based on the arithmetic operations, PKC is broadly

With the rapid increase in the popularity of groupware applications whose security mainly relied on the key being used, which made multi‐party/group secret key agreements significant. However, the brute‐force attacks to interpret the group key made group communication vulnerable. The logical solution to overcome this is changing the group key frequently. In this direction, we propose blockchain‐based multiple shared keys agreement among a group of participants. As with conventional methods, the proposed protocol does not rely on strong random number generation and/or master key. In this technique, the privacy‐preserving smart contract acts as group controller (GC) and forms two parties with each of the other nodes. The GC, while generating these two‐party keys in the first round instead of exchanging one public key, it exchanges “m” public keys with each of the other nodes and generates m2 shared two‐party keys with each of the respective nodes. Now in the second round, GC generates m2 sequential products of two‐party shared keys and stores them securely as private data objects in the privacy‐preserving smart contract. Next GC computes m2sequential public keys to each of the respective nodes by multiplying these products with the inverse of individual members shared keys sequentially of the group nodes in trusted execution environment and shares them with respective group nodes. On receiving respective public keys, each group node computes the multiple multiparty shared keys by multiplying it with their individual shared keys. Furthermore, an upper limit for the number of shared keys obtained in terms of the number of keys exchanged.

Multi-Agent Systems can support e-Healthcare applications for improving quality of life of citizens. In this direction, we propose a healthcare system architecture named smart healthcare city. First, we divide a given city into various zones and then we propose a zonal level three-layered system architecture. Further, for effectiveness we introduce a Multi-Agent System (MAS) in this three-layered architecture. Protecting sensitive health information of citizens is a major security concern. Group key agreement (GKA) is the corner stone for securely sharing the healthcare data among the healthcare stakeholders of the city. For establishing GKA, many efficient cryptosystems are available in the classical field. However, they are yet dependent on the supposition that some computational problems are infeasible. In light of quantum mechanics, a new field emerges to share a secret key among two or more members. The unbreakable and highly secure features of key agreement based on fundamental laws of physics allow us to propose a Quantum GKA (QGKA) technique based on renowned Quantum Diffie–Hellman (QDH). In this, a node acts as a Group Controller (GC) and forms 2-party groups with remaining nodes, establishing a QDH-style shared key per each two-party. It then joins these keys into a single group key by means of a XOR-operation, acting as a usual group node. Furthermore, we extend the QGKA to Dynamic QGKA (DQGKA) by adding join and leave protocol. Our protocol performance was compared with existing QGKA protocols in terms of Qubit efficiency (QE), unitary operation (UO), unitary operation efficiency (UOE), key consistency check (KCC), security against participants attack (SAP) and satisfactory results were obtained. The security analysis of the proposed technique is based on unconditional security of QDH. Moreover, it is secured against internal and external attack. In this way, e-healthcare Multi-Agent System can be robust against future quantum-based attacks.

Summary The rapid increase in health care data breaches with the existing centralized systems emphasizes a decentralized health care system while ensuring reliability, privacy, security, and trust. Further, to ensure trust in the medical community, scientist, and pharmaceutical, it is essential to improve the quality of health care data management. In this direction, we proposed a blockchain‐based decentralized privacy‐preserving EMR management (DPEM), which can ensure accountability and integrity. We propose a four‐layered framework for DPEM consisting of a data preparation layer, access control and security layer, data sharing layer, and data storage layer with the objectives: (i) To provide privacy‐preserving in DPEM, we propose a new elliptic curve‐based content extraction signature (EC‐CES) through which patients can exclude EMR's sensitive information to eradicate leakage of privacy information in the data sharing process. (ii) To provide secure data sharing, blockchain smart contracts are used to define the predefined access permissions of the patients. (iii) To provide secure storage, we use a cloud facility to store actual EMRs, and consortium blockchain is used to store respective indexes of EMRs so that the data leakages of EMRs could be optimized and simultaneously, indexes in consortium blockchain will take care the integrity of EMRs. (iv) To provide access control in data sharing, we adopted ciphertext‐policy attribute‐based encryption (CP‐ABE) access control policy to empower the owners of data to secure the cloud storage and give access to authorized users through the encrypted link to the cloud storage with access control policies blinded. Finally, the security analysis demonstrates that DPEM is an optimized way of achieving EMRs secure data sharing.

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