Conclusion:
This thesis examined the deployment of the Chinese ShangMi (SM) cipher suites within both the Chinese and global TLS ecosystem and assessed their implications for interop- erability and Internet fragmentation. The results show that SM cipher suites have not replaced globally standardized cipher suites but instead coexist with them in a limited and compatibility-oriented manner. Support for SM cipher suites remains restricted to specialized implementations and is closely tied to TLS 1.3 deployment, while global TLS libraries and platforms continue to rely on IETF-standard algorithms. Overall, the findings demonstrate that fragmentation in secure communication protocols is shaped less by cryptographic standards themselves and more by deployment practices, software support asymmetries, protocol version mismatches, and network-level reachability constraints. Even when protocol compatibility exists, regional network controls and operational decisions can prevent successful communication across borders. Taken together, this work highlights that maintaining global interoperability in TLS requires not only standardized cryptography but also aligned deployment practices and open network environments.