25 lines
819 B
Markdown
25 lines
819 B
Markdown
|
+++
|
||
|
|
title = "OPT Controller"
|
||
|
|
+++
|
||
|
|
|
||
|
|
Common crypto software runs on systems with an OS. Our approach is to
|
||
|
|
reduce the attack surface of an operating system with its user programs
|
||
|
|
by delegating the crypto part to a system as simple as possible.
|
||
|
|
|
||
|
|
## System scetch:
|
||
|
|
|
||
|
|
<!-- {{attachment:sketch.gif|system setup|width="500"}} -->
|
||
|
|
|
||
|
|
An AVR controller with keyboard and display is used to gather the plain
|
||
|
|
text which is held only in the controllers RAM. An One Time Pad
|
||
|
|
encryption is performed using a large keyfile stored on the SDCARD
|
||
|
|
attached to the AVR.
|
||
|
|
|
||
|
|
The AVR communicates using an ES8266 module.
|
||
|
|
|
||
|
|
The encrypted text is sent to an central server. That could be done via
|
||
|
|
SMTP or an simple HTTP request.
|
||
|
|
|
||
|
|
The encrypted answer is downloaded and decrypted in the AVR. the plain
|
||
|
|
text is shown on the display attached to the AVR.
|