Lightning Network reaches new milestone as Blockstream completes first end-to-end Bitcoin transaction

Progress on Bitcoin’s Lightning Network continues to advance.

Following French startup Acinq’s promising Lightning routing network trial last week, Montreal-based startup Blockstream has announced the completion of the first end-to-end transaction via the Lightning Network, the much-anticipated technology that will boost the bitcoin network’s transaction processing capabilities.

Dubbed "Lightning's first strike," the team's developers successfully sent a transaction from one party to another using a test version of the Lightning Network, a process that involved invoicing the bitcoin transaction and routing the payment through multiple nodes.

Blockstream's experiment involved sending transactions on the Bitcoin test network, transferring a total of 0.01 BTC, which was used to 'buy' a photo of a cat sitting in front of a sunset.

Although the transaction size may seem insignificant, the trial marks the beginning of the Lightning Network’s move from proof-of-concept to implementation. Most implementations so far have focused on high-level issues such as routing and privacy, rather than demonstrating how to scale bitcoin.

Rusty Russell, a core technical engineer at Blockstream, told CoinDesk:

“We have all the pieces. It’s really exciting. In some ways, it’s really trivial to connect them together. In other ways, it’s really a milestone in making lightning possible.”

Blockstream, like several other startups, has been a contributor to the Lightning Network.

In particular, Russell has been working on a Lightning Network implementation since March 2015. Similarly, Christian Decker, a core technical engineer at Blockstream who joined in August, originally proposed dual-Lightning micropayment channels, another way to develop micropayment channels for the same purpose: scaling Bitcoin.

Internal details

However, Blockstream engineers said their end-to-end implementation is very different from Acinq’s. Rather than focusing on efficient routing, Blockstream engineers are testing a transaction that successfully goes through the network.

The Blockstream blog explains:

"Their work showed that, using a simple analogy, one can create a kind of 'street map' for getting from point A to point B in an efficient way, and our experiment was to walk down those streets."

The test was conducted on the Bitcoin test network.

Russell said:

“This test allows us to get a closer look at real-world implementations of the Lightning Network.”

The engineers also pointed out that the transaction speed was about a fraction of a millisecond, compared to the 10-minute block confirmation time required for transactions executed on the Bitcoin blockchain. They concluded that the results of this test show that the Lightning Network can significantly improve the user experience.

Decker said:

"It was incredible for us. It took us a long time to come to our senses and continue with the test deal."

Future Lightning Network Development

This promising progress will continue in the coming weeks.

All the different Lightning Network project implementers plan to meet in Milan, Italy, following this week’s big bitcoin developer conference Scaling Bitcoin to work on new standards.

Along the way, the plan is to “build a small ecosystem” for micropayment channels on the bitcoin testnet, Decker said. Blockstream is further working on its work in a nearly public way so anyone can try out the technology, or “you can buy something on your own testnet.”

But while Blockstream’s implementation is a viable end-to-end system, engineers say there are a number of other features (in the works) that need to be added to the testnet version.

For example, every node in the test network has global knowledge of the network's topology, so as long as a path is found in the network, an efficient routing system that can be extended to more network nodes is not used.

Somehow, they were able to put the pieces together to complete a working testnet transaction.

“I think it’s incredibly exciting. I’m amazed. Because when you’ve been working in a field for a few years, it’s hard to appreciate how exciting the work is.”