Contained Bitcoin Lightning developer, Joost Jager, has outlined an exploit of the micro-payments network that could result in channels being compromised with very little endeavor and negligible cost.

Nonetheless, he said he's hard at piece of work on a possible solution.

Jager specifies that the assail could be carried out on wumbo channels, which essentially permit larger transactions betwixt mutually agreeing parties on the Lightning network.

A wumbo channel removes the limit to the total amount of Bitcoin that can be held in a regular Lightning channel — which is around $1,760 worth at today's prices. Information technology besides removes the approx. $450 limit to how big an individual payment can be.

Jager said the wumbo channels can be exploited because the channel cannot concur more than than 483 hash and fourth dimension-lock contracts (HTLCs) at any time regardless of its chapters. So a malicious role player sending 483 micro-payments to themselves, and holding on to the HTLCs is enough to incapacitate a channel for up to ii weeks.

The developer demonstrated that this could exist accomplished by using the maximum road length to add loops and more contracts to quickly reach that total for just a minor initial outlay, five.8 million satoshis in this example.

If the script kid is lucky, they only need to send 54 payments to get information technology done. A single tiny channel takes double-digit amounts of Bitcoin out of business organisation.

He added that he had started a new firewall for Lightning nodes project called Excursion Breaker to address this problem. When asked whether this 'griefing attack' is the biggest unsolved set on vector on LN today, he added;

That depends on how you ascertain biggest. There are other attacks that can make you lose money which seems worse. But this one is ane of the biggest in terms of not knowing how to solve it.

With wumbo channels a user can signal that they want to send more BTC than the regular limits and observe a node that is willing to receive. Regular Lightning users sending micropayments will not exist affected but information technology is a much better option for business concern and enterprise payments.

Wumbo channels are growing in adoption and Bitfinex has been the latest to announce support for them;

The word "wumbo" comes from a cartoon series chosen SpongeBob SquarePants, and refers to the thought that 2 parties demand to concur to 'wumbo' together for the transaction to have place.