Lightning Network Daemon

The Lightning Network Daemon (lnd) - is a complete implementation of a Lightning Network node and currently deployed on testnet4 - the Bitcoin Test Network. It utilizes an upcoming upgrade to Bitcoin: Segregated Witness (segwit). The project's codebase uses the btcsuite set of Bitcoin libraries, and is currently dependant on btcd. In the current state lnd is capable of:

• creating channels
• closing channels
• completely managing all channel states (including the exceptional ones!)
• maintaining a fully authenticated+validated channel graph
• performing path finding within the network, passively forwarding incoming payments
• sending outgoing onion-encrypted payments through the network

Lightning Network Specification Compliance

lnd doesn't yet fully conform to the Lightning Network specification (BOLT's). BOLT stands for: Basic of Lightning Technologies. The specifications are currently being drafted by several groups of implementers based around the world including the developers of lnd. The set of specification documents as well as our implementation of the specification are still a work-in-progress. With that said, lnd the current status of lnd's BOLT compliance is:

• BOLT 1: Base Protocol
  • lnd currently utilizes a distinct wire format which was created before the emgergence of the current draft of BOLT specifications. We don't have an init message, but we do have analogues to all the other defined message types.
• BOLT 2: Peer Protocol for Channel Management
  • lnd implements all the functionality defined within the document, however we currently use a different set of wire messages. Additionally,lnd uses a distinct commitment update state-machine and doesn't yet support dynamically updating commitment fees.
• BOLT 3: Bitcoin Transaction and Script Formats
  • lnd currently uses a commitment design from a prior iteration of the protocol. Revocation secret generation is handled by elkrem and our scripts are slightly different.
• BOLT 4: Onion Routing Protocol
• BOLT 5: Recommendations for On-chain Transaction Handling
• BOLT 7: P2P Node and Channel Discovery
• BOLT 8: Encrypted and Authenticated Transport

Installation

In order to build from source, the following build dependencies are required:

• Go: Installation instructions can be found here.

  It is recommended to add $GOPATH/bin to your PATH at this point. Note: If you are building with Go 1.5, then you'll need to enable the vendor experiment by setting the GO15VENDOREXPERIMENT environment variable to 1. If you're using Go 1.6 or later, then it is safe to skip this step.

• Glide: This project uses Glide to manage dependencies as well as to provide reproducible builds. To install Glide, execute the following command (assumes you already have Go properly installed):

  $ go get -u github.com/Masterminds/glide
  

• btcd: This project currently requires btcd with segwit support, which is not yet merged into the master branch. Instead, roasbeef maintains a fork with his segwit implementation applied. To install, please see the installation instructions.

With the preliminary steps completed, to install lnd, lncli, and all related dependencies run the following commands:

$ git clone https://github.com/lightningnetwork/lnd $GOPATH/src/github.com/lightningnetwork/lnd
$ cd $GOPATH/src/github.com/lightningnetwork/lnd
$ glide install
$ go install . ./cmd/...

Updating

To update your version of lnd to the latest version run the following commands:

$ cd $GOPATH/src/github.com/lightningnetwork/lnd
$ git pull && glide install
$ go install . ./cmd/...

Tests

To check that lnd was installed properly run the following command:

go install; go test -v -p 1 $(go list ./... | grep -v  '/vendor/')

IRC

• irc.freenode.net
• channel #lnd
• webchat

Further reading

• Step-by-step send payment guide with docker
• Contribution guide