diff --git a/README.md b/README.md index 1133f12..8e4a2b5 100644 --- a/README.md +++ b/README.md @@ -1,6 +1,46 @@ # Entropy-RNG: Camera-Based Random Number Generator -This project uses a live video feed from a network camera (e.g. an **Axis M1013**) to generate cryptographically secure random numbers. The camera is pointed at a high-contrast, ever-changing scene (e.g. ceiling and lamps) so the pixel data carries genuine entropy. +This project uses a live video feed from a network camera (e.g. an **Axis M1013**) to generate cryptographically secure random numbers. The camera is pointed at a high-contrast, ever-changing scene (e.g. ceiling and lamps) so the pixel data carries genuine entropy. The output can be used locally (feeding the kernel RNG via `rngd`) or served over HTTP so remote systems can pull entropy to seed their own pools. + +--- + +## What Changed + +This section records the rewrite from the original scripts to the current pipeline. Each bullet maps to a commit in `git log`. + +### Core RNG fix (the important one) +The original code computed a SHA-256 of the camera frame into a variable named `entropy` and then **discarded it**, drawing instead from the OS CSPRNG via `secrets.randbits()`. The camera contributed nothing — the output was just relabeled `/dev/urandom`. + +- Replaced with a **NIST SP 800-90A HMAC-DRBG** (SHA-256) seeded from the frame hash. The camera now genuinely contributes entropy. +- The DRBG is reseeded every frame, so output changes even when camera noise is modest. +- Added `--interval` for loop rate control, `--out` for writing raw bytes to a FIFO, mutual exclusion of `--loop`/`--single`, and bit-multiple validation. + +### Health checks +- Added `health.py` with **FIPS 140-2 continuous tests** (monobit, runs, long-run) on the raw JPEG bytes before hashing. +- A frozen, all-identical, or degraded frame is rejected and never seeds the DRBG. +- Runs thresholds are doubled because we count 0-runs and 1-runs together. +- `--no-health` disables the checks for debugging. + +### Cleanup +- Removed `entropy-rng-cam.py` and `entropy-rng-opencv.py`, which were superseded by `entropy.py` and carried the same unused-entropy bug. +- Removed the empty 0-byte `file`. +- Added `requirements.txt` with pinned dependencies. + +### HTTP service + container deployment +- Added `api.py` — a FastAPI app that runs the camera producer in a background thread and serves the latest entropy blob over HTTP. +- Added `Dockerfile` for container builds, with a healthcheck against `/healthz`. +- All config is via environment variables for containers. + +### Auth (simple by design) +- Single shared secret via `X-API-Key` header, controlled by `ENTROPY_API_KEY`. +- Empty key means no auth, so you can start open and lock down by setting one env var. +- The API layer is where HMAC-signed blobs or mTLS plug in later — no architecture change needed. + +### Tests +- Added `test_entropy.py` — 16 tests covering the DRBG, health checks, a bit-balance smoke test, and API auth gating. All pass without a camera (the producer is stubbed). + +### Docs +- Rewrote this README and `notes.md` to match the new pipeline and commands. --- @@ -16,14 +56,32 @@ This project uses a live video feed from a network camera (e.g. an **Axis M1013* ## Requirements +### Software - Python 3.10+ -- `opencv-python`, `fastapi`, `uvicorn`, `pytest` +- Python packages: `opencv-python`, `fastapi`, `uvicorn`, `pytest` +### System libraries (Debian/Ubuntu) +OpenCV needs runtime libraries that are not pip-installed: +```bash +sudo apt-get install libgl1 libglib2.0-0 +``` + +### Install Python dependencies ```bash pip install -r requirements.txt ``` -On Debian/Ubuntu you also need OpenCV runtime libs: `apt-get install libgl1 libglib2.0-0`. +### Hardware +- An IP webcam serving an MJPEG stream over HTTP (e.g. Axis M1013 at `http://192.168.0.200/mjpg/video.mjpg`). +- The camera must be pointed at a dynamic, high-contrast scene. A static frame will fail health checks and be rejected. + +### For the kernel-RNG flow +- Linux with `rngd` installed (`rng-tools` package). +- `sudo` privileges to run `rngd`. + +### For container deployment +- Docker (or any OCI-compatible runtime) for local containers. +- Kubernetes for orchestrated deployment (optional). --- @@ -142,3 +200,4 @@ Covers the HMAC-DRBG (determinism, reseed, length, reseed limit), health checks - Point the camera at a dynamic scene. A static frame will fail health checks and be rejected. - The DRBG is reseeded from each frame, so output changes even if the camera noise is modest. - Auth is a single shared secret for now. When you need per-client keys, rotate to HMAC-signed blobs or mTLS — the API layer is where that plugs in. +- The 256-bits-per-frame entropy credit is conservative. If you want a defensible number for your specific camera, run `ent` or `rngtest` on a captured sample.