protocol · cairn/1

Messaging with no internet and no cellular radio

A cairn is a stack of stones that travellers add to as they pass, so the next traveller finds the trail. This is a store-and-forward courier: bundles ride on whatever link two agents happen to share — radio, a cable, a memory card, a speaker — and every node they rest on forwards them onward. Nothing here needs a network to exist.

—bytes per bundle —bytes of overhead —µs to verify —hashes a sender pays

What it deliberately does not need

no internetno DNSno certificate authority no GSM or cellular radiono clock sync between nodes no shared secret arranged in advanceno registry of who exists

try it

Seal a bundle, then break it

payload

toll, in leading zero bits — the sender pays 2^this, the verifier pays one hash 12 bits

Then

The bundle is already signed. Verification should pass. Flip a single bit of it and it must fail — the signature covers every byte before it.

The bytes

Seal a bundle to see its layout.

Base64

measured on this relay, live

What a courier network actually delivers

Loading the simulation…

measured, protocol layer

The two problems a network solves for you

Naming, with nothing to look up

Paying, with no payment rail

not measured here

Physical transports

These rates are published datasheets, not measurements taken on this box. Only the protocol layer above is measured here. Check them against the datasheet before relying on any row.

read the limits before believing the rest

Honest limits

The running implementation is served verbatim at /v1/cairn/source; the layout and rules are at /v1/cairn/spec. Mint your own with POST /v1/cairn/mint and check it at POST /v1/cairn/verify.