STCPv2 technology

Secure transport from kernel to application

STCPv2 is a secure transport architecture built to give applications one communication model across Linux, Raspberry Pi and Zephyr-based embedded systems. The design separates application protocols from platform-specific networking while keeping the transport implementation close to the operating system where appropriate.

AF_STCP / PF_STCPRust coreLinux kernelRaspberry PiZephyrnRF9151
Core technology

What STCPv2 is

STCPv2 is not an application protocol such as MQTT or CoAP. It is the secure transport layer underneath them. Applications can retain familiar communication semantics while STCP handles secure peer transport and platform-specific integration.

Native Linux socket family

The Linux implementation integrates with the kernel socket layer as AF_STCP / PF_STCP = 45. The socket interface implements familiar operations including bind, listen, accept, connect, send and receive.

Shared Rust protocol core

Protocol logic is implemented in a shared Rust core rather than duplicated for every target. Linux and Raspberry Pi use the kernel integration around that core, while embedded targets expose the same architecture through their platform layer.

Secure transport layer

Security belongs to the transport architecture instead of being added independently by every application. This lets higher-level protocols use one common secure communication substrate.

Carrier abstraction

The STCP core is separated from the underlying carrier. Carrier implementations can map STCP traffic onto available network transports without changing the application-facing STCP model.

Cross-platform SDK

The STCP SDK is structured around a common API with target-specific platform implementations. The same SDK application is intended to build for x86 Linux, Raspberry Pi Linux and nRF9151 / Zephyr.

Application protocols above STCP

MQTT, CoAP and peer-to-peer software sit above STCP. They are consumers of the transport layer, not part of the transport itself, keeping application logic independent from platform networking details.

Architecture

One stack, multiple execution environments

The architecture has a stable application-facing layer and isolates the parts that must differ between operating systems and embedded platforms. On Linux, STCP is exposed through the native socket subsystem; on embedded systems, the same protocol architecture is reached through the SDK platform implementation.

Applications & application protocolsMQTT · CoAP · peer-to-peer software · custom STCP applications
STCP SDK / common application APIPlatform-independent interface used by application code.
STCPv2 protocol coreConnection state, secure transport logic, framing and shared protocol behavior.
Platform integrationLinux kernel socket implementation on Linux/Raspberry Pi; Zephyr platform implementation on embedded targets.
Carrier & network interfaceThe underlying network path used to move STCP traffic between peers.

x86-64 Linux

Native kernel module and AF_STCP socket API for development, profiling and production-style host testing.

Raspberry Pi / ARM64

Linux kernel integration using the same STCP architecture on an ARM64 edge platform.

nRF9151 / Zephyr

Embedded implementation for constrained devices and cellular/IoT deployment scenarios.

Linux kernel architecture

On Linux, STCP behaves like a native networking facility rather than a userspace wrapper around an unrelated application API.

Socket-facing layer

Applications use the Linux socket model. The STCP kernel module connects socket operations to the shared STCP core and maintains connection, accept and receive state.

Protocol-facing layer

The Rust core contains shared STCP behavior and is called by the platform integration for lifecycle, connection, send/receive and carrier processing operations.

Design goal: keep application code independent from the transport implementation. A program should not need a different communication architecture merely because it moves from a Linux host to Raspberry Pi or an embedded Zephyr target.

Built above STCP

Higher-level integrations demonstrate how existing application protocols can use STCP as their transport foundation.