Support for TPM Using PyOpenSSL with Azure IoT SDK

[IniterWorker]

First, this is a proof of concept of the implementation. It is stable and we are actively using it in our current project. However, we believe it is necessary to contribute these changes upstream, as they affect two projects: azure-iot-sdk-python to support PyOpenSSL and paho.mqtt.python.

This Draft is mainly for early feedback purpose.

Reference/Link to the issue solved with this PR (if any)

• Does iot-sdk-python support PKCS#11? #1093
• Q: Python-based device provisioning with Custom HSM #278
• Use DPS with TPM in Python #1066
• Is it possible "simulated TPM device using Python device SDK (azure-iot-sdk-python)" is running in linux OS? and how? #339
• Passing a device certificate to provisioning client on linux #254
• How to connect to IoT Hub using protected private key in TPM #1179

Description of the problem

There is currently no straightforward way to use a TPM with the azure-iot-sdk-python.

Description of the solution

This PR leverages PyOpenSSL to provide a custom context with OpenSSL PKCS#11 support, enabling the use of a TPM. This requires changes to both the azure-iot-sdk-python and paho.mqtt.python to support the PyOpenSSL context.

• See Draft: Add support for PyOpenSSL in paho.mqtt.python eclipse-paho/paho.mqtt.python#849 for related changes in paho.mqtt.python.

[AndreRicardo-Zoetis]

+1
Would also like to see this.

[cartertinney]

I'll bring this up as a potential feature, but this seems more of a candidate for a major revision as it rethinks a lot of assumptions about SSL and API shape.