Add BIP-352 Silent Payments scanning support #26
Description
Hi! I've implemented BIP-352 Silent Payments scanning specified here. Before opening a PR, I wanted to check if this is something you'd consider merging.
You can see the implementation on my fork:
https://github.com/pzafonte/kernel-node/tree/silent-payments
What it adds:
- Scanning primitives (ECDH, tagged hashing, output key derivation)
- Input public key extraction (P2WPKH, P2TR, P2PKH, P2SH-P2WPKH)
- Transaction and block-level scanning
- In-memory wallet with UTXO tracking and spend detection
- Transaction history
- Binary persistence (save/load wallet state)
- Cap'n Proto IPC interface (import-keys, balance, history)
- 52 unit tests
All code lives in a single new module (src/silentpayments.rs) plus
IPC additions to existing files. No changes to existing node logic.
Happy to split into smaller PRs if preferred.