Watchtowers fortify the Lightning Network against fraud
” A Bitcoin scaling solution, the Lightning Network adds a second layer to the Bitcoin blockchain that allows users to create payment channels between any two parties. The payment channels can be closed after use or kept open indefinitely. Because they’re set up between two parties, transactions are instant and fees are extremely low. Lightning makes it possible for Bitcoiners to use the payment network to pay for items of low value, such as a cup of coffee, without incurring the larger fees and longer confirmation times of the main Bitcoin blockchain. But while the network has seen significant adoption — with 8,789 nodes running 34,650 channels at the time of writing — the technology is still in the experimental stage and it involves certain risks, including the potential for fraud. By supervising the activity on the network, the new ‘watchtowers’ aim to eliminate the possibility that the party on the other side of your channel could cheat you out of your funds.
The software architecture — which was initially proposed in the original Lightning white paper of 2016 — has been implemented into the Lightning Network Daemon with June’s update. It will allow network participants to enlist the protection of a transaction monitoring service that prevents users from committing fraud by rebroadcasting old transactions. ”