AW-Tool Sign ECDSA Documentation

The aw-tool-sign-ecdsa package provides functionality for performing ECDSA signing operations using Lit Protocol's PKPs (Programmable Key Pairs). This tool enables secure signing of arbitrary messages or transactions while enforcing policy-based controls.

Files Overview (in src/lib)

1. ipfs.ts

Handles IPFS CIDs for different environments (development, testing, production). Falls back to default CIDs if the build output is not found.

Key Features:

• Default CIDs: Predefined CIDs for datil-dev, datil-test, and datil environments
• Dynamic CID Loading: Attempts to load CIDs from dist/ipfs.json at runtime
• Fallback Mechanism: Uses default CIDs if the file is missing or unreadable

2. lit-action.ts

Contains the main logic for executing a Lit Action to perform ECDSA signing operations.

Key Features:

• PKP Info Retrieval: Fetches PKP details (token ID, Ethereum address, public key) from the PubkeyRouter contract
• Delegatee Validation: Verifies that the session signer is a valid delegatee for the PKP
• Policy Enforcement: Validates message prefixes against the allowed prefixes in the policy
• Message Signing: Signs messages using the PKP's public key via Lit Actions
• Error Handling: Comprehensive error handling and response formatting

3. policy.ts

Defines and validates the ECDSA signing policy schema using Zod.

Key Features:

• Policy Schema: Validates policy fields:
  • type: Must be 'SignEcdsa'
  • version: Policy version string
  • allowedPrefixes: Array of allowed message prefixes
• Encoding/Decoding: Converts policies to and from ABI-encoded strings using ethers
• Type Safety: Uses Zod for schema validation and TypeScript type inference

4. tool.ts

Configures the ECDSA signing tool for different Lit networks.

Key Features:

• Parameter Schema: Validates required parameters:
  • pkpEthAddress: The Ethereum address of the PKP
  • message: The message to be signed
• Network Configuration: Creates network-specific tools for each supported Lit network
• Tool Definition: Implements the AwTool interface with:
  • Name and description
  • Parameter validation and descriptions
  • Policy integration with SignEcdsaPolicy