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TPM Integration Guide

TPM solutions from Variscite

How to Integrate a Trusted Platform Module into Your Server / Client Application with Variscite SoMs

A Trusted Platform Module (TPM) is a dedicated security component designed to securely generate, store and manage cryptographic keys and other sensitive data. In embedded systems, it establishes a hardware-based root of trust that also enables features such as unique device identity.

Variscite offers both HW and SW based solutions, either as a dedicated HW TPM chip performing security relevant tasks in dedicated temper-resistant hardware, or as a firmware-based solution based on SEC-TPM, leveraging Arm TrustZone.

This guide walks through integrating a Trusted Platform Module (TPM) into a simple client/server application running on Variscite SoMs.

We’ll start with a minimal example and progressively add security features - beginning with plain-text communication and ending with TPM-backed private keys. The goal is to make the journey approachable for engineers who are new to TLS concepts, while still providing practical value for those already familiar with secure communication.

If you already have a solid understanding of TLS and mutual authentication, feel free to jump directly to Part 4, where we introduce TPM integration and discuss how it strengthens your application's security model.

What we'll build

The tutorial is structured in incremental parts:

Part 1 - Basic Client/Server in Python

We start with a minimal Python client and server communicating in clear text. This provides a simple baseline to understand the mechanics of the application before introducing security layers.

Part 2 - Adding TLS with Server Authentication

Next, we enable TLS to encrypt communication and authenticate the server. This protects against eavesdropping and ensures the client is talking to the expected endpoint.

Part 3 - Adding Client Authentication (Mutual TLS)

We extend the setup to mutual TLS (mTLS), allowing the server to verify that only authorized devices can connect.

Part 4 - Introducing the TPM

Here we discuss how a TPM enhances security by protecting private keys in hardware and strengthening device identity. We also briefly discuss manufacturing and deployment.

Part 5 - TPM-Backed Private Key

We modify the Python client to use a private key secured by the TPM.

Part 6 - TPM Integration in a C Application

We repeat the TPM-backed key integration for a C-based client application.

Part 7 - Summary and Advanced Topics

We summarize the concepts and provide an outlook on more advanced TPM topics, such as authorization mechanisms.

This step-by-step approach allows you to understand not only how to integrate a TPM, but also why it improves the security posture of your system.

Additional Resources

To make it easier to follow along, we provide:

  • Complete source code for client.py, server.py, and client.c for each part. The documentation focuses on the incremental changes between steps, but the full source code is available here