feat: support remote signer #4
Description
Add support for remote signing backends to improve key security in production deployments.
Currently, the oracle uses local keystores where the private key is decrypted and held in memory. For production environments handling significant value, best practice is to use remote signers where keys never touch application memory.
Proposed Backend
Web3Signer - Industry standard for Ethereum signing (used by SSV network, Prysm, Lighthouse and more)
- REST API for signing
- Supports keystores, HSMs, and cloud KMS internally
- https://docs.web3signer.consensys.io/
Configuration Example
wallet:
type: "web3signer"
web3signer_url: "http://localhost:9000"