<p>Watchtowers are monitoring for attempted Lightning channel closes using revoked states and when they identify one they can broadcast the justice transaction claiming <strong>all</strong> (eltoo may change this in future but that is not possible under current consensus rules) the funds in the channel for the &quot;cheated&quot; party. This attempted closing of a channel using a revoked state may be done accidentally or maliciously. The security assumption for Lightning relies on being online 24/7 (or close to it) so that you can respond to an attempted channel close with a revoked state with your own justice transaction in a timely manner. With a watchtower (or multiple watchtowers in place) a party in a Lightning channel no longer has to be online 24/7 as they can rely on the watchtower to monitor the chain and respond if required.</p>

CC BY-SA 4.0
2021-11-16T04:27:59.400Z
What if the watchtower goes offline for that duration?
Patoshi パトシ
CC BY-SA 4.0
2021-11-16T09:13:15.570Z
Of course, you're not protected if both you and your watchtower go offline for a significant period. Like with an insurance policy, if your insurer goes bankrupt you aren't covered. A watchtower's primary job is to stay online. You could have multiple watchtowers which reduces the probability of them all going offline at the same time though.
Michael Folkson
CC BY-SA 4.0
2021-11-15T16:51:52.323Z
2021-11-15T16:51:52.323Z
Michael Folkson
<p>I'm still learning about Bitcoin lightning and learned about watchtowers. What are they doing exactly for the network and its users?</p>

<lightning-network><watchtower>
What are Bitcoin Lightning Watchtowers exactly doing for the network and users?
Patoshi パトシ
# What are Bitcoin Lightning Watchtowers exactly doing for the network and users?

(Asked by: username_0 on 2021-11-15)

I'm still learning about Bitcoin lightning and learned about watchtowers. What are they doing exactly for the network and its users?

**Tags:** lightning-network, watchtower


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## 1 answers

### Answer by username_1 on 2021-11-15. Score: 4

Watchtowers are monitoring for attempted Lightning channel closes using revoked states and when they identify one they can broadcast the justice transaction claiming **all** (eltoo may change this in future but that is not possible under current consensus rules) the funds in the channel for the "cheated" party. This attempted closing of a channel using a revoked state may be done accidentally or maliciously. The security assumption for Lightning relies on being online 24/7 (or close to it) so that you can respond to an attempted channel close with a revoked state with your own justice transaction in a timely manner. With a watchtower (or multiple watchtowers in place) a party in a Lightning channel no longer has to be online 24/7 as they can rely on the watchtower to monitor the chain and respond if required.

> **Comments:**
> **username_0**: What if the watchtower goes offline for that duration?  
> **username_1**: Of course, you're not protected if both you and your watchtower go offline for a significant period. Like with an insurance policy, if your insurer goes bankrupt you aren't covered. A watchtower's primary job is to stay online. You could have multiple watchtowers which reduces the probability of them all going offline at the same time though.  

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