4 ms·
Just crazy enough to work! I love it. One hole I can poke in the concept is to copy the IR heartbeat signal and retransmit while destroying the mesh. >Besides
by 1970-01-01 3y ago
Just crazy enough to work! I love it. One hole I can poke in the concept is to copy the IR heartbeat signal and retransmit while destroying the mesh.
>Besides power transfer from stator to rotor, we need a reliable, bidirectional data link to transmit mesh status and a low-latency heartbeat signal. We chose to transport an 115 kBd UART signal through a simple IR link for a quick and robust solution. The link’s transmitter directly drives a standard narrow viewing angle IR led.
- camtarn 3y agoYeah. They did flag up earlier that wireless transmission between HSM and monitor would have to be encrypted. I wonder whether they missed that out in the prototype due to time issues, or whether the microcontroller they chose made it infeasible.
- crote 3y agoThat is trivially solved by using the output of a PRNG as heartbeat signal. You can't copy a signal which constantly and unpredictably changes.
- 1970-01-01 3y agoNo, its not trivial https://en.wikipedia.org/wiki/Random_number_generator_attack#Attacks https://en.wikipedia.org/wiki/Random_number_generator_attack...
- crote 3y agoJust because potential attacks exist doesn't mean it isn't a solved problem in practice. There are plenty of well-research PRNG algorithms out there, some of which are used in very high-profile applications like TLS and have been exposed to hostile parties for over a decade. If you are building an HSM you are almost guaranteed to already have a battle-hardened implementation of one lying around.
- 1970-01-01 3y agoIt really depends on what you expect as a threat. Ask a Casino owner if they fully trust an RNG system and you will get laughed at. Randomness is not encryption and can be broken with enough knowledge of the system.