Distinguishing mutual and unilateral channel closing in the Bitcoin blockchain

Ever wonder how can one tell the difference between a mutual and an unilateral Lightning Network channel closing?

Gaurav AgrawalLightning Channels can be ended two different way:

a mutual, cooperative closing simply called Closing Transaction an unilateral, uncooperative closing called Commitment Transaction

It is easy to make a difference: Lightning Network Specifications say the locktime field of mutual closing is always 0. Let’s see how to check this in practice!

We will find funding transaction for a channel using Lightning Network Explorer 1ml.com. Then we find hash ID of spending transaction using Bitcoin Block Explorer btc.com. Then we get spending transaction using web based interface to the Bitcoin API: chainquery.com. And we compare it’s locktime to zero.

What a Mutual Closing looks like

We can see some closed channels here: https://1ml.com/channel?order=closedchannels

Take this example: https://1ml.com/channel/567676753988747264