https://github.com/BlockstreamResearch/secp256k1-zkp/blob/d22774e248c703a191049b78f8d04f37d6fcfa05/include/secp256k1_ecdsa_s2c.h

Everything Blockstream does is opensource, I have never understood the hatred of the community towards blockstream, I guess ignorance is very bold.

As notes:

- Jade is fully opensource, both hardware, software and firmware.

- Because of this you can build your own Jade (DIY) avoiding supply chain issues.

- It solves the problem of secure elements through a multi-signature pin system.

- If you don't understand how such a multi-signature pin system works and you are fucking paranoid, you can build your own oracle server. This doesn't really make any sense if you understand how blockstream's oracle server works, other than blockstream may stop providing service.

- Jade is really inexpensive compared to other competitors.

- You can do air-gapped transactions.

- For those who criticize Bluetooth you can disable it through firmware so that it is totally inoperative due to the lack of low level driver.

Honestly, Jade is a HWW made for the community and by cryptographers and not for profit (in my opinion), blockstream does crazy things that don't exactly benefit their pockets (also in my opinion), that's why I don't understand many times the hate that is poured against them.

Here you have the instructions to make your own Jade:

https://github.com/Blockstream/Jade/tree/master/diy