Regarding "Trezor" bitcoin wallet (I don't know how many models there are, or much about this). I just saw this below on twitter. Unsure if referring to same model.
The model below is alleged to be insecure with what is said to be older (or previous) firmware. The original article mentions pin codes having been added (to something) to address the previous vulnerability.
I don't understand exactly how this unit is vulnerable myself, maybe limited to a particular circumstance, or maybe it is super easy, I don't know.
"Extracting the Private Key from a TREZOR Bitcoin Wallet with a $70 Oscilloscope"
https://blog.adafruit.com/2018/06/07/extracting-the-private-key-from-a-trezor-bitcoin-wallet-with-a-70-oscilloscope/"Extracting the Private Key from a TREZOR ... with a 70 $ Oscilloscope"
https://jochen-hoenicke.de/trezor-power-analysis/
"However, also the generation of the public key may leak some information via a side channel. Until firmware 1.3.2 of TREZOR this was not PIN protected. Therefore, I investigated whether it is possible to use a side channel to recover the private key from the public key computation.""Also, if you have passphrase protection, this attack does not work even with firmware 1.3.1, so you may consider adding that, too."The main article simply mentions there being a 'seed' involved in some of the calculations. I am no cryptographer and I don't know anything about bitcoin wallets, but with no further description of this seed, it sounded weird to me. I am also wondering what the difference between 'private key' and 'master private key' would be.