I was going to rebut this, but @RandomSmith got there first:
I’ll just add that while the ESP32 does indeed have a tiny amount of RAM, it has plenty enough to handle basic cryptographic operations such as key signing and certificate verification.
Nor do you need as much power as an ESP32 offers. Zigbee, the IOT protocol used by Philips Hue, supports encrypted comms. Those light bulbs are not exactly bursting with CPU power! (We’ll ignore the fact that early versions of Zigbee did a poor job of managing that encryption so it was easily broken 
)
In the United States, it is explicitly illegal to reverse engineer any software. Exceptions can be granted by the Patent and Trademark Office, but they are time limited and rarely granted. (It’s a bad law, purchased by the software industry for the low low price of campaign donations to committee members.)
Can’t speak for rest of the world.
Yes:
…so long as you don’t mind not being able to use their Bambu Handy app. But there are other phone apps available:
- Bambu Companion: Bambu Companion for iPhone. No cloud needed (I use this)
- Joint Craft: Joint Craft - 3D Printer app App - App Store (I use this too)
- PandaBeFree for iPhone: https://www.reddit.com/r/BambuLab/comments/1rsl7o3/i_built_a_free_opensource_ios_app_for_bambu_lab/
- LanBu for Android: https://www.reddit.com/r/BambuLab/comments/1llym3a/open_beta_lanbu_lan_only_mode_print_monitoring/
Some of these require Developer Mode or LAN Only Mode. Some use Bambu’s own cloud authentication system to communicate with the printer, which I imagine Bambu doesn’t love but has been ignoring.
Edit: This is what Joint Craft looks like:
