Biblio

With the rapid development of Internet of things (IOT) and big data, the number of network terminal devices and big data transmission are increasing rapidly. Traditional cloud computing faces a great challenge in dealing with this massive amount of data. Fog computing which extends the computing at the edge of the network can provide computation and data storage. Attribute based-encryption can effectively achieve the fine-grained access control. However, the computational complexity of the encryption and decryption is growing linearly with the increase of the number of attributes. In order to reduce the computational cost and guarantee the confidentiality of data, distributed access control with outsourced computation in fog computing is proposed in this paper. In our proposed scheme, fog device takes most of computational cost in encryption and decryption phase. The computational cost of the receiver and sender can be reduced. Moreover, the private key of the user is generated by multi-authority which can enhance the security of data. The analysis of security and performance shows that our proposed scheme proves to be effective and secure.

In blockchain-based systems, malicious behaviour can be detected using auditable information in transactions managed by distributed ledgers. Besides cryptocurrency, blockchain technology has recently been used for other applications, such as file storage. However, most of existing blockchain- based file storage systems can not revoke a user efficiently when multiple users have access to the same file that is encrypted. Actually, they need to update file encryption keys and distribute new keys to remaining users, which significantly increases computation and bandwidth overheads. In this work, we propose a blockchain and proxy re-encryption based design for encrypted file sharing that brings a distributed access control and data management. By combining blockchain with proxy re-encryption, our approach not only ensures confidentiality and integrity of files, but also provides a scalable key management mechanism for file sharing among multiple users. Moreover, by storing encrypted files and related keys in a distributed way, our method can resist collusion attacks between revoked users and distributed proxies.

The strong development of the Internet of Things (IoT) is dramatically changing traditional perceptions of the current Internet towards an integrated vision of smart objects interacting with each other. While in recent years many technological challenges have already been solved through the extension and adaptation of wireless technologies, security and privacy still remain as the main barriers for the IoT deployment on a broad scale. In this emerging paradigm, typical scenarios manage particularly sensitive data, and any leakage of information could severely damage the privacy of users. This paper provides a concise description of some of the major challenges related to these areas that still need to be overcome in the coming years for a full acceptance of all IoT stakeholders involved. In addition, we propose a distributed capability-based access control mechanism which is built on public key cryptography in order to cope with some of these challenges. Specifically, our solution is based on the design of a lightweight token used for access to CoAP Resources, and an optimized implementation of the Elliptic Curve Digital Signature Algorithm (ECDSA) inside the smart object. The results obtained from our experiments demonstrate the feasibility of the proposal and show promising in order to cover more complex scenarios in the future, as well as its application in specific IoT use cases.