Hashes, Nonces, and Replay Attacks on the Arduino

from blog Lord.io, | ↗ original
When J.J. and I designed the Hacker School door system, one of our problems was keeping the system secure. There are two parts of the door system, DoorDuino, which is an Arduino that unlocks the door, and Doorbot, which is a Sinatra server that registers users and receives text messages. These two pieces talk to each other over HTTP. When it...