Skip to content

README.md

Latest commit

 

History

History
38 lines (26 loc) · 3.34 KB

README.md

File metadata and controls

38 lines (26 loc) · 3.34 KB
Raw

ARC-403 Interface (draft)

This package defines the canonical interface for ARC-403 authorization contracts — the compliance hook the Token and MultiToken contracts in this repository call on every hooked transfer and burn when an auth_contract is configured.

Draft status: the ARC-403 specification is still under active discussion on the forum. This interface tracks the draft as implemented by the tokens in this repository and may change if the specification changes.

Contracts

Noir limits each package to a single contract, so the two hook variants live in two packages under this directory:

  • Arc403Authorizer (package arc403_interface, this directory) — the fungible-token hook:
    • authorize_private(from: AztecAddress, amount: u128, selector: Field) (private)
    • authorize_public(from: AztecAddress, amount: u128, selector: Field) (public)
  • Arc403MultiTokenAuthorizer (package arc403_multitoken_interface, in multitoken/) — the multi-token (per-id) hook:
    • authorize_private(from: AztecAddress, id: Field, amount: u128, selector: Field) (private)
    • authorize_public(from: AztecAddress, id: Field, amount: u128, selector: Field) (public)

The function bodies in these packages are empty stubs: the artifacts define the ABI and are not meant to be deployed. Never deploy the stubs as a real authorizer — an empty hook body approves everything. To write an authorization contract, implement these exact signatures in your own contract and revert to deny the triggering token operation. The selector argument is the selector of the token function that invoked the hook, letting a policy distinguish e.g. burns from transfers.

Why a stub contract?

This mirrors aztec-packages' own protocol_interface packages (FeeJuice, ContractInstanceRegistry), whose empty-bodied #[aztec] contracts exist purely to provide a generated Noir call interface. The #[aztec] macro derives the caller-side interface exclusively from function names, parameter types, and #[external] attributes — bodies are never read — so calls through a stub are byte-identical to calls through the real implementation. The alternative idiom (raw FunctionSelector::from_signature + context.call_*_function, as used by authwit) was considered and rejected: it leaves implementers with no compilable artifact to conform to, and forfeits compile-time type-checking at the token's call sites.

Consuming the interface from Noir

arc403_interface = { git = "https://github.com/AztecProtocol/aztec-standards", directory = "src/arc403_interface" }
# or, for the per-id multi-token variant:
arc403_multitoken_interface = { git = "https://github.com/AztecProtocol/aztec-standards", directory = "src/arc403_interface/multitoken" }
use arc403_interface::Arc403Authorizer;
// e.g. from a contract that needs to call an authorizer:
Arc403Authorizer::at(auth_contract).authorize_public(from, amount, selector);

Test doubles used by this repository's own suites live in src/token_contract/src/test/test_authorization_contract and src/multitoken_contract/src/test/multitoken_authorization_contract; they are spy implementations of this interface.