pairlink 0.2.0

Local-network pairing between two phones over TCP: an out-of-band secret, a nonce-bound HMAC handshake, replay rejection, heartbeats and takeover. Pure Dart.

Changelog

All notable changes to this project will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

0.2.0 - 2026-09-05

Added

• PairEndpoint.id and PairSecret.pairId({required brand}): a public name for a pairing, the first four bytes of HMAC-SHA256 over the secret, in hex. Null for a typed code by construction — thirty-two bits of a keyed hash over 128 random bits reveal nothing, while the same hash over four digits would be a ten-thousand-row lookup table. It lets two phones that remember each other recognise each other BEFORE they connect, so a search never spends a stranger's attempt budget on a handshake that could not verify.

Fixed

• PanelSession reported one dropped socket TWICE. The transport's onDone emitted PanelDisconnected without detaching, so the idle timer stayed armed and fired again fifteen seconds later. A consumer that reacts to a drop with a bounded retry loop got the second report after it had finished, and started over with a fresh budget — the "stopped trying to reconnect, then connected on its own" shape seen on two phones on 2026-09-05.
• PanelSession reported a handshake that never completed as a drop. attach already says so by returning false; the extra event made a failed reconnect attempt look like a fresh outage.

0.1.0 - 2026-09-04

Added

• First released version: the v3 wire protocol (PROTOCOL.md), OutletSession, PanelSession, PairInvite, PairSecret, the socket transport and the discovery contracts, with the skeptic test suite.
• PairIdentity: the application's brand, mDNS serviceType and QR scheme are one value the application declares and passes in. Two applications on this protocol never share a key space.

Changed

• Breaking. OutletSession, PanelSession and PairInvite require an identity; PairInvite.tryParse takes one; PairSecret.deriveKey takes a brand. The constants kWireBrand and kServiceType are gone.