Tamper-evident paper-mail box for secure distribution of one-time pads

A simple device for secure transportation of OTP keycards, solves the problem of secure distribution of encryption keys. Tampering will be detected.

A logical sequel to RNG-5 hardware random number generator- one-time pad crypto system, very secure, virtually unbreakable peer-to-peer communication!

One-wire interface for LCD: When using a small MCU (e.g. like ATTiny), it would be very convenient to save those few pins for something else. A standard textual LCD needs 4 data lines, 2 lines for RS and E (enable) and even one more if you want to turn it on/off (all together 7 lines).

I started this project when asked by a friend of mine, a guitar player, to try to make a better tuner than those commercially available. Their usual problems are bad digital signal processing and small and hardly leggible displays.

Zener diode noise is processed, captured and recorded on an SD card. Passes all NIST tests for random signals.