Watchtowers send LN breach remedy transactions (justice transactions) when they detect that one of their client’s counterparty has broadcast an outdated channel close transaction.
The service provided by watchtowers allows their clients to go offline for significant amounts of time without having to worry about their funds being stolen by a counterparty. Watchtowers are not entrusted with any funds, just the responsibility of monitoring the block chain and broadcasting transactions, although breach remedy transactions can be designed so that the watchtower receives a portion of the safeguarded funds if their services are needed.
Optech newsletter and website mentions
- 2019-12-28 2019 year-in-review: watchtowers
- 2019-12-11 Discussion about watchtowers for eltoo payment channels
- 2019-12-04 Watchtower BOLT specification proposed
- 2019-09-25 Watchtower storage costs
- 2019-07-03 LND 0.7.0-beta release with initial watchtower support
- 2019-06-19 LND PR #3133 adding support for altruist watchtowers
- 2019-03-19 LND PR #2618 implementing private watchtower support
- 2019-01-22 LND PR #2439 adding a default policy for the watchtower
- 2019-01-22 LND PR #2448 adding a standalone watchtower
- 2018-11-20 LND PR #2124 adding support for detecting and using onchain spends
- 2018-10-30 LND PRs #1535 and #1512 adding server-side communication for watchtowers
- 2018-08-07 LND PR #1543 adding watchtower version 0 encoding and encryption