EIP712 Signed-Typed Data

The Delegatable framework uses the EIP712 signed-typed data specification for signing Delegations and Invocations.

EIP712 core benefits are human-readable and machine-verifiable data structures. In other words, Users can more easily understand what they're signing (and the side-effects) and we can still process the signature on-chain, for minimal additional gas-costs.

If you are not familiar with the EIP712 specification it's recommended to review the following resources:

• Specification: https://eips.ethereum.org/EIPS/eip-712
• Guide: https://medium.com/metamask/eip712-is-coming-what-to-expect-and-how-to-use-it-bb92fd1a7a26
• Signing Data: https://docs.ethers.io/v5/api/signer/#Signer-signTypedData
• Verifying Data: https://docs.ethers.io/v5/api/utils/signing-key/#utils-verifyTypedData

Data Structures

The Delegatable framework uses multiple data structures to enable counterfactual, revocable delegation.

• Delegation
  • delegate: address
  • authority: bytes32
  • caveats: Caveat[]
• SignedDelegation
  • delegation: Delegation
  • signature: bytes
• Caveat
  • enforcer: address
  • terms: byes
• Invocation
  • transaction: Transaction
  • authority: ReplayProtection
• Invocations
  • batch: Invocation[]
  • replayProtection: ReplayProtection
• SignedInvocation
  • invocations: Invocation[]
  • signature: bytes
• Transaction to: address gasLimit: uint256 data: bytes
• ReplayProtection
  • nonce: uint
  • queue: uint
• IntentionToRevoke
  • delegationHash: bytes32
• SignedIntentionsToRevoke
  • signature: bytes
  • intentionToRevoke: IntentionToRevoke

Diving Into the Nested Data Structure

The Delegatable framework uses 10 distinct data structures.

Top-level data types (e.x. Invocation) also include nested data types like Transaction. The nested data types, like Transaction continue to define data structures matching native transactions with properties like to, gasLimit and data.

export const delegatableTypes = {
  EIP712Domain: [
    { name: 'name', type: 'string' },
    { name: 'version', type: 'string' },
    { name: 'chainId', type: 'uint256' },
    { name: 'verifyingContract', type: 'address' },
  ],
  Invocation: [
    { name: 'transaction', type: 'Transaction' },
    { name: 'authority', type: 'SignedDelegation[]' },
  ],
  Invocations: [
    { name: 'batch', type: 'Invocation[]' },
    { name: 'replayProtection', type: 'ReplayProtection' },
  ],
  SignedInvocation: [
    { name: 'invocations', type: 'Invocations' },
    { name: 'signature', type: 'bytes' },
  ],
  Transaction: [
    { name: 'to', type: 'address' },
    { name: 'gasLimit', type: 'uint256' },
    { name: 'data', type: 'bytes' },
  ],
  ReplayProtection: [
    { name: 'nonce', type: 'uint' },
    { name: 'queue', type: 'uint' },
  ],
  Delegation: [
    { name: 'delegate', type: 'address' },
    { name: 'authority', type: 'bytes32' },
    { name: 'caveats', type: 'Caveat[]' },
  ],
  Caveat: [
    { name: 'enforcer', type: 'address' },
    { name: 'terms', type: 'bytes' },
  ],
  SignedDelegation: [
    { name: 'delegation', type: 'Delegation' },
    { name: 'signature', type: 'bytes' },
  ],
  IntentionToRevoke: [{ name: 'delegationHash', type: 'bytes32' }],
  SignedIntentionToRevoke: [
    { name: 'signature', type: 'bytes' },
    { name: 'intentionToRevoke', type: 'IntentionToRevoke' },
  ],
};