The paper "Improved blockchain-based user authentication protocol with ring signature for internet of medical things" addresses the challenges of secure and privacy-preserving authentication in the Internet of Medical Things (IoMT). The authors propose an Improved Chain Code Blockchain-based Key Agreement Authentication Mechanism (CCBKAAM) that utilizes SM9-based Secure Threshold Ring Signature (SM9-STRS) to enhance security and privacy. This mechanism employs multiple key generation-based cipher identification algorithms for parameter maintenance and integrates a threshold ring signature to overcome the limitations of single-key generation schemes. The CCBKAAM uses Chain Codes over the Ethereum network for block construction during mutual user authentication and an Improved PBFT Voting protocol for consensus. The protocol stores identities and associated parameters on the blockchain to support communication during authentication, effectively resisting various attacks. Performance analysis shows that the proposed mechanism reduces communication and computation overhead by 32.19% and 28.94%, respectively, and minimizes storage overhead by up to 35.42%. The introduction highlights the importance of IoT and cloud computing in healthcare, emphasizing the need for secure and real-time data processing. It discusses the challenges of integrating blockchain with IoMT, including real-time response, mobility, processing power, traffic overhead, and storage. The paper identifies the need for a blockchain-based authentication protocol to ensure confidentiality, integrity, and availability in decentralized IoMT environments. The proposed work aims to address these challenges by integrating IoMT with blockchain technology, leveraging its decentralized, reliable, traceable, and open features to enhance privacy, confidentiality, and interoperability. The research questions focus on the integration of IoMT and blockchain, addressing issues such as device compatibility and interoperability.The paper "Improved blockchain-based user authentication protocol with ring signature for internet of medical things" addresses the challenges of secure and privacy-preserving authentication in the Internet of Medical Things (IoMT). The authors propose an Improved Chain Code Blockchain-based Key Agreement Authentication Mechanism (CCBKAAM) that utilizes SM9-based Secure Threshold Ring Signature (SM9-STRS) to enhance security and privacy. This mechanism employs multiple key generation-based cipher identification algorithms for parameter maintenance and integrates a threshold ring signature to overcome the limitations of single-key generation schemes. The CCBKAAM uses Chain Codes over the Ethereum network for block construction during mutual user authentication and an Improved PBFT Voting protocol for consensus. The protocol stores identities and associated parameters on the blockchain to support communication during authentication, effectively resisting various attacks. Performance analysis shows that the proposed mechanism reduces communication and computation overhead by 32.19% and 28.94%, respectively, and minimizes storage overhead by up to 35.42%. The introduction highlights the importance of IoT and cloud computing in healthcare, emphasizing the need for secure and real-time data processing. It discusses the challenges of integrating blockchain with IoMT, including real-time response, mobility, processing power, traffic overhead, and storage. The paper identifies the need for a blockchain-based authentication protocol to ensure confidentiality, integrity, and availability in decentralized IoMT environments. The proposed work aims to address these challenges by integrating IoMT with blockchain technology, leveraging its decentralized, reliable, traceable, and open features to enhance privacy, confidentiality, and interoperability. The research questions focus on the integration of IoMT and blockchain, addressing issues such as device compatibility and interoperability.