Lightning network ushered in a heavy upgrade! The long-awaited "watch tower" will fill the missing link.

The lightning network's "watchtowers" — the long-awaited next step in protecting lightning network security — are coming soon.

Watchtowers have long been considered a missing part of the Bitcoin lightning network layer, as this part is critical to combating fraud on this experimental, chain-level Layer 2 network, which allows Bitcoin to pay. Become faster and more scalable. With the release of LND software version 0.7 in June, Lightning Labs will launch the most complete lightning network watch tower to date.


When someone uses a lightning network, it is necessary for people using the network to stay online to ensure that their "transaction opponents" are not trying to steal the funds. But this is obviously a nightmare for user experience; for example, customers don't have to monitor Wells Fargo's accounts every day to make sure they are not being cheated.

The watchtower "monitors" the old "states" broadcast. In other words, if a bad actor tries to spread an old deal—adding extra money to himself—the watch tower will punish him.

Therefore, the watchtower outsources this anti-fraud function, so users do not have to perform this kind of monitoring themselves.

Conner Fromknecht, director of cryptography at Lightning Labs, has been the driving force behind this implementation, even at a virtual lightning conference in April to make design decisions (such as how the watch tower made privacy decisions) A speech was delivered. In the past year, Lightning Labs CTO Olaoluwa Osuntokun and other team members worked with him to make design decisions.

As Osuntokun explained to CoinDesk:

"An important factor (in my opinion) is that now we have a direct deterrent against any possible violation attempts. Now the lookout tower code is public and has a strong inhibitory effect on the attacker because the attacker knows Potential victims are likely to have a watchtower monitoring them."

The concept of the watchtower is not new, as it was originally proposed in the original Lightning Network White Paper in 2015 to prevent fraud.

In fact, as CoinDesk reported, Lightning Labs has been working on this feature since at least early last year. But the upcoming release may be the most advanced implementation to date for real-world use.

Running a "tower"

Since the birth of the Watchtower, there have been a number of technical tests, including MIT's Lit, an open source project led by lightning network white paper co-author Tadge Dyja, and the blockchain service company BitFury's Lighting Peach project. .

But the upcoming release of LND, one thing to look forward to is that users will be able to click on the watchtower to see the real participants who are testing the lightning network today.

There is also Bitcoin Lightning Wallet, which implements the watchtower on the so-called "Olympus Server". However, Osuntokun pointed out that the LND watch tower code can be run by anyone.

Osuntokun told CoinDesk: "The importance of this version is that once deployed, any routing node can run its own watchtower to protect its infrastructure. Any company that uses (Lightning Network) can now start to operate the watch tower to protect it. Your own node."

But not everyone wants to run their own watchtowers, especially because they consume a lot of data. So people can start connecting to the tower outside to protect their money.

As more such towers emerge, users can connect to as many towers as possible, as long as they want to make sure they don't believe that only one tower can make sure their money is safe. However, this situation may not happen immediately.

Osuntokun expects that the introduction of the watchtower will lead to a "safer network" that paves the way for users to make payments on networks that were previously considered unsafe. This includes allowing users to invest more money into the lightning channel through a technology named SpongeBob, he said.

'Ecash' tokens and more

This upcoming release is a big step forward for the long-awaited technology, but the Osuntokun and Lightning Lab teams still have plans to improve the lookout tower software.

For example, those running the watchtower will run for free. But Lightning Labs is planning an upgrade that allows people to pay a small fee to the watchtower, thus providing users with "economic incentives" to run these watch towers.

Interestingly, however, there is some debate about the need for this approach.

Lightning Network White Paper co-author Dryja believes that if the lightning network works, you should not actually use the watch tower too much. This is because, if the watchtower works, the bad elements should not try to broadcast the status of the old passage, because the watchtower will ensure that the bad elements lose their money when making such an attempt.

If there is a watchtower in operation, this arrangement should theoretically be a barrier to preventing people from trying to defraud. Therefore, they are rarely used and are therefore paid. But it is difficult to predict this outcome until the watchtower is deployed and begins to draw attention to users.

As they tried to protect the privacy of the watchtower as much as possible, the team was working on a way to make the payments to the watchtower more private.

To this end, they are considering creating "some sort of Ecash token." Ecash is an anonymous currency created by cryptographer David Chaum in the 1980s and is considered one of the pioneers of bitcoin.

The idea is to allow Lightning Network users to pay for the watchtower in a “non-linkable” way.

Then there is still a big step to go. Currently, LND is the only lightning network client that follows an official specification with a running watchtower. Therefore, other implementations also need to implement their own watch towers.