Proxy re-encryption (PRE) provides a promising solution for applications requiring efficient and secure ciphertext conversion, such as secure cloud data sharing. While the one with the function of ciphertext evolution is more desirable for some long-term schemes involving key update. Recently, Yao et al. constructed an identity-based conditional proxy re-encryption scheme simultaneously supporting authorization and ciphertext evolution. However, its delegated ciphertext can be re-authorized, which may cause the authorization to exceed the original delegator’s expectation. In contrast, the single-hop PRE authorization scheme may be more appropriate for systems requiring better control over authorization. In this paper, an identity-based proxy re-encryption scheme with single-hop conditional delegation and multi-hop ciphertext evolution (IBPRE-SHCD-MHCE) is proposed. Also, its description, construction, and security analysis are given. The analysis and experimental comparison results show that the proposed scheme has improved the computational efficiency and storage consumption compared with the two underlying schemes.

In the Internet of Vehicles (IoVs), vehicles generate and disseminate information, which makes the related vehicular services realized. However, the IoVs is an untrusted environment. Vehicles cannot evaluate the credibility of the received information, which makes it a challenge to implement data sharing in IoVs. Blockchain, constantly directed main attention, are considered as a feasible solution to address the challenge, due to its advantages of decentralization, unforgeability, and collective maintenance. The consensus mechanism of blockchain requires the miners in the system with strong computing power for mining, while the computing power of nodes in IoVs is limited, which restricts the application of blockchain in IoVs. In fact, the application of blockchain in IoVs can be implemented by employing edge computing. The key entity of edge computing is the edge servers(ESs). Roadside nodes (RSUs) can be deployed as ESs of edge computing in IoVs. In this article, we study the ESs deployment scheme for covering more vehicle nodes in IoVs, and propose a randomized algorithm to calculate approximation solutions. Finally, we simulated the performance of the proposed scheme and compared it with other deployment schemes.

In this paper, we investigate the problem of optimal road side units (RSUs) placement in Vehicular Ad Hoc Network (VANET) on a highway, which enables the VANET maintain a good connectivity. Our goal is to find out minimal number of road side units, such that the vehicles could communicate with RSUs. These road side units are connected by wire. We develop a randomized algorithm to deploy road side units in the VANET. It gives an approximation to the optimal distance to guarantee the information can be passed to RSUs from the accident site via the VANET. Simulations are conducted to show the performance of our proposed method.