gotlcp

Two Chinese cryptographic transport standards, GB/T 38636-2020 for TLCP and GM/T 0128-2023 for DTLCP, both implemented in Go, each with its own set of documentation.

gotlcp is a Go implementation of the Transport Layer Cryptography Protocol, built to the GB/T 38636-2020 standard and based on TCP transport, also known as GMSSL. Alongside it the library covers DTLCP, the datagram version, which follows GM/T 0128-2023 and runs over UDP for scenarios that cannot rely on reliable TCP transport.

The DTLCP feature list is specific. The server requires dual certificates, a signature certificate and an encryption certificate. Session reuse works through an LRU cache and session tickets. The handshake is a four state machine covering preparing, sending, waiting, and finished. On top of that there is exponential backoff retransmission and stateless cookie protection against denial of service.

Documentation is split by protocol. The TLCP side links to guides on the protocol introduction, the handshake flow, cipher suites, certificate and key preparation for dual certificates, client and server config field details, and HTTPS configuration for TLCP clients and Gin or Fiber servers. The DTLCP side points to a quick start guide, a config and usage guide with security recommendations, and a design document covering the protocol stack architecture, record layer, handshake protocol, flight mechanism, retransmission state machine, and cookie based DoS protection. Together they are meant to be the reference for building TLCP and DTLCP applications.

The acknowledgements matter here. The SM series algorithms are implemented by the emmansun gmsm project, which optimizes algorithm efficiency through CPU instruction sets. The TLCP protocol code is trimmed from the Go 1.19 crypto tls module in the Go standard library. That gives anyone reading the repo a clear picture of where the cryptographic code originates.

• Source 1 · Project repository
• Source 2 · README