https://github.com/ppad-tech/bolt4
Onion routing protocol, per BOLT #4.
https://github.com/ppad-tech/bolt4
haskell lightning onion
Last synced: about 4 hours ago
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Onion routing protocol, per BOLT #4.
- Host: GitHub
- URL: https://github.com/ppad-tech/bolt4
- Owner: ppad-tech
- License: mit
- Created: 2026-04-18T03:31:17.000Z (2 months ago)
- Default Branch: master
- Last Pushed: 2026-04-20T08:28:28.000Z (about 2 months ago)
- Last Synced: 2026-04-20T09:27:30.732Z (about 2 months ago)
- Topics: haskell, lightning, onion
- Language: Haskell
- Homepage:
- Size: 132 KB
- Stars: 0
- Watchers: 0
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG
- License: LICENSE
- Agents: AGENTS.md
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README
# ppad-bolt4
[](https://hackage.haskell.org/package/ppad-bolt4)
[](https://docs.ppad.tech/bolt4)
A pure Haskell implementation of [BOLT #4][bolt4] (onion routing) from
the Lightning Network protocol specification, including packet
construction and processing, error handling, and route blinding.
## Usage
A sample GHCi session:
```
> :set -XOverloadedStrings
>
> -- construct an onion packet for a 3-hop route
> import qualified Crypto.Curve.Secp256k1 as Secp256k1
> import qualified Data.ByteString as BS
> import qualified Lightning.Protocol.BOLT4.Construct as Construct
> import qualified Lightning.Protocol.BOLT4.Process as Process
> import Lightning.Protocol.BOLT4.Types
>
> -- session key (32 bytes random, use CSPRNG in production)
> let sessionKey = BS.replicate 32 0x41
>
> -- node keys (in production, these come from the network)
> let Just hop1Sec = Secp256k1.parse_integer (BS.replicate 32 0x01)
> let Just hop1Pub = Secp256k1.mul Secp256k1._CURVE_G hop1Sec
>
> -- build a minimal payload
> let payload = emptyHopPayload { hpAmtToForward = Just 1000
> , hpOutgoingCltv = Just 144 }
> let hop = Construct.Hop hop1Pub payload
>
> -- construct packet (returns packet + shared secrets for error handling)
> let assocData = BS.replicate 32 0x00 -- typically payment_hash
> let Right (packet, secrets) = Construct.construct sessionKey [hop] assocData
>
> -- process at receiving node
> let result = Process.process (BS.replicate 32 0x01) packet assocData
> case result of
> Right (Process.Receive info) -> print (riPayload info)
> _ -> putStrLn "not final hop"
```
## Modules
The library is organized into the following modules:
* `Lightning.Protocol.BOLT4.Construct` - onion packet construction
* `Lightning.Protocol.BOLT4.Process` - onion packet processing
* `Lightning.Protocol.BOLT4.Error` - failure message handling
* `Lightning.Protocol.BOLT4.Blinding` - route blinding support
* `Lightning.Protocol.BOLT4.Types` - core data types
* `Lightning.Protocol.BOLT4.Codec` - serialization (BigSize, TLV)
* `Lightning.Protocol.BOLT4.Prim` - cryptographic primitives
## Documentation
Haddocks are hosted at [docs.ppad.tech/bolt4][hadoc].
## Security
This is a pre-release library that claims no security properties whatsoever.
## Development
You'll require [Nix][nixos] with [flake][flake] support enabled. Enter a
development shell with:
```
$ nix develop
```
Then do e.g.:
```
$ cabal build
$ cabal test
$ cabal bench
```
[bolt4]: https://github.com/lightning/bolts/blob/master/04-onion-routing.md
[hadoc]: https://docs.ppad.tech/bolt4
[nixos]: https://nixos.org/
[flake]: https://nixos.org/manual/nix/unstable/command-ref/new-cli/nix3-flake.html