With the rapid development of technologies such as the Internet of Things (IoT) and cloud computing, portable health clinics (PHCs) have been realized and widely used in telemedicine. Relying on the significant advantages of 5G communications, China has actively promoted the construction of smart healthcare and built a multi-function and high-quality telemedicine information service platform.The realization of telemedicine represented by PHCs is inseparable from the technical support of remote data-sharing systems. At present, the remote data-sharing system combining IoT and the cloud server (CS) has attracted wide attention due to its flexibility and efficiency, but its privacy and security issues are rarely studied. Considering the sensitivity of medical data, this paper endeavors to study the security and privacy issues in the PHC data-sharing system. As a result, in the PHC system, this study achieves the secure uploading of IoT awareness data, normalization of personalized ciphertexts, dynamic multi-user fine-grained access control, and efficient decryption operations, and it also presents formal security verification. The specific innovations of this study are as follows: (1) The classical proxy re-encryption (PRE) and attribute-based encryption algorithms are improved, and an IPRE-TO-FAME combined encryption mechanism is proposed to ensure the data-sharing security of the PHC system with cloud-edge collaboration. (2) To address the challenge of key updates caused by many highly distributed IoT terminals, this paper uses the idea of PRE to realize the key updates on the basis of the unilateral transformation without changing the keys to IoT terminals. Meanwhile, the re-encryption entities can be regarded as fully trusted in the application scenarios of this study, which is different from the situation of the conventional PRE mechanism, where the re-encryption entities are usually untrusted third-party servers. Therefore, the conventional PRE algorithm is improved, and an efficient improved PRE (IPRE) algorithm is put forward to adapt to the scenarios proposed in this study. (3) The classical fast attribute-based message encryption (FAME) mechanism is improved to enable dynamic multi-user fine-grained access control. In this way, users can easily use portable intelligent devices to access data anytime and anywhere. The security proofs, theoretical analysis, and experimental results reveal that the proposed solution is highly secure and practical, which is an effective way to ensure secure PHC data sharing.