pamoja-lorawan

LoRaWAN 1.0.x MAC framing for pamoja: build and parse data-frame PHYPayloads with the message integrity code and payload encryption the spec mandates, plus the over-the-air-activation join exchange, so a long-range node speaks LoRaWAN, no_std and allocation-free. The secured-packet half ahead of the radio driver.

The same capability in every language

LoRaWAN 1.0.x MAC framing for the pamoja SDK.

LoRaWAN is how a low-power node reaches a network kilometres away over a license-free radio, which is why it is the SDK's first-class answer for rural and remote reach. The pamoja-lora crate gives the link budget, the exact time a transmission spends on air; this crate gives the bytes that go in it: the secured LoRaWAN frame.

A LoRaWAN frame is not just a payload with an address. The standard wraps every frame in two cryptographic guarantees, because a long-range public-band link is wide open: a message integrity code keyed to the network proves the frame is authentic and intact, and the payload is encrypted to the application so only its owner can read it. This crate builds and verifies exactly that, with no radio and no allocation:

• Session - an activated device's address and session keys. It encodes an uplink or downlink data frame, encrypting the payload and appending the MIC, and decodes one received, verifying the MIC before decrypting.
• Uplink and Downlink - the data frame to send, built up from the fields a sender sets (confirmed, adaptive data rate, acknowledgement, frame options).
• RxData - a decoded frame: its header fields and its recovered payload.
• Device - the root credentials for over-the-air activation: it builds the join-request a device broadcasts and turns the network's join-accept into a ready Session, deriving the session keys the spec prescribes.
• JoinRequest and JoinGrant - the other half of that exchange, so a deployment can run its own network instead of joining someone else's: verify the request a device sent, then grant it an address and sign the reply. Both sides derive the same session keys from the same nonces, with no key ever on the air.
• FrameHeader - what a frame says about itself before any key is involved: its message type, the device address, and the counter. A receiver holding many sessions reads this first to find the one a frame belongs to, then decodes.

The cryptography is the LoRaWAN construction over AES-128: an AES-CMAC MIC and an AES keystream for the payload, with the device address and frame counter folded into both so a frame cannot be lifted out of its place in the stream. Driving the radio arrives with the hardware-I/O layer; this is the secured-packet half ahead of it.

Examples

use pamoja_lorawan::{Session, Uplink};

// A node activated with a device address and its two session keys.
let session = Session::new(0x2601_1BDA, [0x2B; 16], [0x99; 16]);

// Encode a confirmed uplink reading; the payload is encrypted and the MIC appended.
let frame = session
    .encode_uplink(&Uplink::new(42, 1, b"temp=4.8").confirmed())
    .unwrap();

// The network, holding the same session, verifies and decrypts it.
let rx = session.decode(frame.as_bytes(), 42).unwrap();
assert!(rx.confirmed());
assert_eq!(rx.payload(), b"temp=4.8");

License

MIT - part of the pamoja workspace: one memory-safe Rust core with bindings for every language.