With the development of communication and information technologies, the telemedicine system has infiltrated many aspects of medicine field. It allows doctors to simultaneously diagnose patients in different areas, which provides great convenience to people. However, the increasing medical data brings serious challenges to people, such as data storage and processing. To reduce data management costs and enjoy convenient services, more and more individuals and medical institutions prefer to store data in the cloud. Recently, many public key encryption with keyword search (PEKS) schemes have been designed to address the security and privacy of the outsourced data. However, most of the existing schemes support only single-keyword search, and cannot suitable for multi-user environment. To resolve these issues, we construct a certificateless public key encryption with conjunctive keyword search scheme for multi-user system (mCLPECK), in which the same data only needs to be encrypted once and can be searched by multi-receiver. At the same time, the mCLPECK scheme supports multi-keyword search. Furthermore, we show the proposed scheme can resist chosen keyword attacks, and has lower storage and computation overhead compared to other related schemes.

随着通信和信息技术的发展，远程医疗系统已经渗透到医学领域的许多方面。它使医生可以同时诊断不同地区的患者，为人们提供了极大的便利。但是，不断增长的医疗数据给人们带来了严峻的挑战，例如数据存储和处理。为了降低数据管理成本并享受便捷的服务，越来越多的个人和医疗机构倾向于将数据存储在云中。最近，已经设计了许多带有关键字搜索（PEKS）方案的公钥加密来解决外包数据的安全性和私密性。但是，大多数现有方案仅支持单关键字搜索，并且不适合多用户环境。为了解决这些问题，我们为多用户系统（mCLPECK）构造了带有联合关键字搜索方案的无证书公钥加密，其中相同的数据仅需加密一次即可被多接收者搜索。同时，mCLPECK方案支持多关键字搜索。此外，我们表明，与其他相关方案相比，该方案可以抵抗选定的关键字攻击，并具有较低的存储和计算开销。