hackypi.

1. 01 · Why I built it

   Showing a risk without causing one.

   A penetration test sometimes has to prove that a plugged-in USB device is a way in. I wanted a device that proves it safely, and nothing else.

2. 02 · The hard part

   From a demo to a platform.

   It began as a one-file demo. I rebuilt it in phases into firmware with a state machine, an approval gate and an evidence chain, and released it after testing on the real board.

Who stays in controlIt ships disarmed, fails closed on any bad setting, and every scoped step waits for the operator's yes.

1. 01

   Set up per engagement

   Target OS, keyboard layout, engagement ID and policies go in a settings file, because a USB keyboard cannot detect the host on its own. Every value is checked at boot.

2. 02

   Fail closed

   Any error in that file forces it to disarmed, where it only shows status and sends nothing.

3. 03

   Look before touching

   Once armed it counts down three seconds on screen, identifies the host and runs read-only checks.

4. 04

   Ask first

   Each scoped step waits for the operator's approval. A no, or no answer in time, drops it back to disarmed.

5. 05

   Clean up and seal

   It releases every key, then seals the audit log on the microSD card with SHA-256 hashes.

• A strict state machine

  Twenty-four states with only legal moves between them, so it can never jump from idle to typing.

• Permission with an end date

  Authorization expires, and is checked against the target's OS, host and subnet before anything runs.

• Read-only by rule

  A safety check stops any reconReconnaissance: mapping everything a target exposes before testing it. (Reconnaissance: mapping everything a target exposes before testing it.) step that would change the host.

• Proof of silence

  It counts every keystroke it sends, and tests assert that the count stays at zero while disarmed.

• Evidence you can check

  A JSON audit log on the microSD card, with a SHA-256 manifest that shows if anything was altered.

• A bench self-test

  A test mode checks the screen, card, keyboard and memory before an engagement, then stops.

1. 01 · A security awareness talk

   Showing the risk safely.

   Plugged in disarmed, it shows its status and sends zero keystrokes.

2. 02 · A booked, scoped test

   Proving the access path.

   Armed for one target: a countdown, read-only checks, one approved step, then cleanup and sealed evidence.

3. 03 · Proving it fails safe

   The wrong target.

   A wrong target, an expired authorization or an out-of-scope host is refused, with zero keystrokes sent.