How to send a message to a MAVLink2 drone signed by Mission Planner using pymavlink

This is an introduction to sending messages to signed drones using Python code.
It utilizes the MAVLink2 and a Python library for MAVLink called pymavlink.
However, it is assumed that signatures have already been configured using Mission Planner.

【System Reruirements】

・Python：3.10.9
・pymavlink：2.4.37
・SITL：ArduCopter V4.4.0
・Mission Planner：1.3.80

【Set up signature】

Select [SETUP] on the toolbar and click [Advanced] > [Mavlink Signing]

Then click [Add] and enter a friendly name in the input field, and click [OK].

Next, enter the string you wish to set as your signature key in the input field and click [OK].
Communication is performed with the key set here.

Finally, click [Use] to activate the signature.

You are now ready to set up your signature.

【Attention】

We have tested the software using ArduPilot's SITL, but please be aware that it may not function correctly in other environments.
It is intended only to send messages to drones. It is not intended to enable full communication with the drone.
The Python code is simple, about 30 lines.
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