I would like to have a physical key to decrypt Linux machines at boot. This is just an idea and I would like to know if there are already projects or established methods to achieve this. Let me explain better. I would like to have an usb device full of random data no partition, then make this thumb read only. First of all: is this possible? Is there some kind of bit that would prevent data write? Something like the SD physical lock, just not physical. Then: what encryption with Linux? I would like to have a pre-boot authentication with simmetrical encryption.. With the hash of the random data key as password.
And a last question: are there some kind of ASIC usb devices to speedup encryption?
Thank you all.