ERC5564Announcer.sol

Overview

The ERC5564Announcer contract is designed to facilitate the broadcasting of transactions involving stealth addresses by emitting an Announcement event. This event contains relevant information that can be used to reconstruct the transaction and validate its parameters.

Code: `ERC5564Announcer.sol` (opens in a new tab)

Events

Announcement

The Announcement event is emitted when the announce function is called. Here are the key components of this event:

schemeId (uint256): Identifier corresponding to the applied stealth address scheme (e.g., 1 for secp256k1 as specified in ERC-5564 (opens in a new tab)).
stealthAddress (address): The computed stealth address for the recipient.
caller (address): The address that called the announce function.
ephemeralPubKey (bytes): Ephemeral public key used by the sender to derive the stealthAddress.
metadata (bytes): Arbitrary data to emit with the event. The first byte MUST be the view tag. The remaining metadata can be used by the senders as per their requirements (refer to ERC-5564 (opens in a new tab) for recommended metadata structure).

Event Signature

event Announcement(
  uint256 indexed schemeId,
  address indexed stealthAddress,
  address indexed caller,
  bytes ephemeralPubKey,
  bytes metadata
);

Functions

announce

The announce function is used by integrators to emit the Announcement event. It takes the following parameters:

schemeId (uint256): Identifier corresponding to the applied stealth address scheme.
stealthAddress (address): The computed stealth address for the recipient.
ephemeralPubKey (bytes): The ephemeral public key used by the sender.
metadata (bytes): Arbitrary data to emit with the event. The first byte MUST be the view tag. The remaining metadata can be used freely by the senders.

Function Signature

function announce(
  uint256 schemeId,
  address stealthAddress,
  bytes memory ephemeralPubKey,
  bytes memory metadata
) external

Description

When called, this function emits the Announcement event with all the parameters supplied to it.

Usage

To use the announce function, you need to pass the required parameters as per the function signature:

contract MyContract {
    ERC5564Announcer public announcer;
 
    constructor(address announcerAddress) {
        announcer = ERC5564Announcer(announcerAddress);
    }
 
    function myAnnounceFunction(uint256 _schemeId, address _stealthAddress, bytes memory _ephemeralPubKey, bytes memory _metadata) public {
        announcer.announce(_schemeId, _stealthAddress, _ephemeralPubKey, _metadata);
    }
}