Privacy preservation in healthcare monitoring systems has always been a concern for both patients and doctors. To address this issue, many protocols have been designed. In this article, we examine the proposed scheme by Nasr Esfahani and colleagues, evaluating it from a security perspective. Their proposed scheme uses a three-layer hierarchical template chain to store and maintain critical medical information of patients in a centralized and secure manner. Additionally, by using Zero-Knowledge Proof (ZKP) and ring signature methods, they demonstrate that their scheme protects medical data against both internal and external attacks. According to potential scenarios, the Nasr Esfahani et al. protocol has shown good performance against many attacks, such as storage attacks and replay attacks, but it is vulnerable to integrity violation attacks. The success probability of the attacks presented in this article is one, and the complexity is only a single execution of the protocol.