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would it be difficult/possible to use this as a smart card with the proper code?
also great for espionage
Interestingly, Joe Grand's OpticSpy uses Tomu as an example optical covert channel: https://www.crowdsupply.com/grand-idea-studio/opticspy
Neat little device, looks like a Yubikey clone. One could get a similar device by hacking a Logitech unifying receiver, which contains a ..16MHz 8051 clone in it, and a radio to spare.
Earlier quoted context omitted.
thats ultimately the intent, to build a Yubikey-like security key, with everything open down through the firmare to the details of the soc
One key (pardon the pun) requirement of a 2FA key is that it can't be cloned - how would this be prevented? Can the microprocessor be locked to prevent reading its flash memory?
Earlier quoted context omitted.
thats ultimately the intent, to build a Yubikey-like security key, with everything open down through the firmare to the details of the soc
One key (pardon the pun) requirement of a 2FA key is that it can't be cloned - how would this be prevented? Can the microprocessor be locked to prevent reading its flash memory?
would it be difficult/possible to use this as a smart card with the proper code?
GnuK ( http://www.fsij.org/doc-gnuk/ ) implements an OpenGPG Smart Card. Unfortunately, it targets STM32 chips with 128KB flash and 20KB DRAM, and the EFM32HG309 in the Tomu is only 64KB/8KB. I don't know how much work it would be to squeeze the code into the Tomu.
Of course the GnuK site lists some STM32 boards designed specifically to run GnuK. Or if you don't care about open hardware you can buy a $2 STLink clone on aliexpress and flash GnuK on it.
Earlier quoted context omitted.
thats ultimately the intent, to build a Yubikey-like security key, with everything open down through the firmare to the details of the soc
One key (pardon the pun) requirement of a 2FA key is that it can't be cloned - how would this be prevented? Can the microprocessor be locked to prevent reading its flash memory?
The only way to clear that bit is to erase the entire flash, with the notable exception of the user data section, so don't put the secret in there :).
Relevant recent discussion: https://news.ycombinator.com/item?id=17587673
I've bought some of the official versions in their KickStarter and whenever I buy through some company/research funding - but can also recommend the cheaper Chinese implementations to be just as good for projects.