Here is an example hardware signing device in the coldcard: https://store.coinkite.com/store

I first thought I saw this in your hand, and not a phone.

The faraday cage can be used to help protect from your HSD’s secrets from being stolen. This is approaching tin foil hat levels, which some may say is healthy.

😆

A Faraday cage is a metal mesh or foil structure that blocks electromagnetic emissions... Not anything sexual unless you want it to be.