Update ERC-5564: Move to Last Call

ERCS/erc-5564.md

@@ -1,18 +1,20 @@
 ---
 eip: 5564
 title: Stealth Addresses
-description: Private, non-interactive transfers and interactions
+description: Private, non-interactive transfers and engagements
 author: Toni Wahrstätter (@nerolation), Matt Solomon (@mds1), Ben DiFrancesco (@apbendi), Vitalik Buterin (@vbuterin)
 discussions-to: https://ethereum-magicians.org/t/eip-5566-stealth-addresses-for-smart-contract-wallets/10614
-status: Review
+status: Last Call
+last-call-deadline: 2024-04-30
 type: Standards Track
 category: ERC
 created: 2022-08-13
+requires: 6538
 ---
 
 ## Abstract
 
-This specification establishes a standardized method for interacting with stealth addresses, which allow senders of transactions or transfers to non-interactively generate private accounts exclusively accessible by their recipients. Moreover, this specification enables developers to create stealth address protocols based on the foundational implementation outlined in this ERC, utilizing a singleton contract to emit the necessary information for recipients. In addition to the base implementation, this ERC also outlines the first implementation of a cryptographic scheme, specifically the SECP256k1 curve.
+This specification establishes a standardized method for interacting with stealth addresses, which allow senders of transactions or transfers to non-interactively generate private accounts exclusively accessible by their recipients. Moreover, this specification enables developers to create stealth address protocols based on the foundational implementation outlined in this ERC, utilizing a singleton contract deployed at `0x55649E01B5Df198D18D95b5cc5051630cfD45564` to emit the necessary information for recipients. In addition to the base implementation, this ERC also outlines the first implementation of a cryptographic scheme, specifically the SECP256k1 curve.
 
 
 ## Motivation
@@ -87,17 +89,15 @@ function computeStealthKey(
 
 The implementation of these methods is scheme-specific. The specification of a new stealth address scheme MUST specify the implementation for each of these methods. Additionally, although these function interfaces are specified in Solidity, they do not necessarily ever need to be implemented in Solidity, but any library or SDK conforming to this specification MUST implement these methods with compatible function interfaces.
 
-A 256 bit integer (`schemeId`) is used to identify stealth address schemes. A mapping from the schemeId to its specification MUST be declared in the ERC that proposes to standardize a new stealth address scheme. It is RECOMMENDED  that `schemeId`s are chosen to be monotonically incrementing integers for simplicity, but arbitrary or meaningful `schemeId`s  may be chosen. Furthermore, the schemeId MUST be added to [this overview](../assets/eip-5564/scheme_ids.md). These extensions MUST specify:
+A 256 bit integer (`schemeId`) is used to identify stealth address schemes. A mapping from the schemeId to its specification MUST be declared in the ERC that proposes to standardize a new stealth address scheme. It is RECOMMENDED  that `schemeId`s are chosen to be monotonically incrementing integers for simplicity, but arbitrary or meaningful `schemeId`s  may be chosen. This ERC introduces schemeId `1` with the following extensions:
 
-- The integer identifier for the scheme.
+- `1` is the integer identifier for the scheme, 
+
+- `viewTags` MUST be included in the announcement event and is used to reduce the parsing time for the recipients. 
 
-- The algorithm for encoding a stealth meta-address (i.e. the spending public key and viewing public key) into a `bytes` array, and decoding it from `bytes` to the native key types of that scheme.
-
-- The algorithm for the `generateStealthAddress` method.
-
-- The algorithm for the `checkStealthAddress` method.
-
-- The algorithm for the `computeStealthKey` method.
+- SECP256k1 is the algorithm for encoding a stealth meta-address (i.e. the spending public key and viewing public key) into a `bytes` array, and decoding it from `bytes` to the native key types of that scheme. 
+- 
+- SECP256k1 with view tags will be used in `generateStealthAddress`, `checkStealthAddress`, and `computeStealthKey` methods.
 
 This specification additionally defines a singleton `ERC5564Announcer` contract that emits events to announce when something is sent to a stealth address. This MUST be a singleton contract, with one instance per chain. The contract is specified as follows:
 
@@ -156,18 +156,18 @@ The new address format for the stealth meta-address extends the chain specific a
 Thus, a stealth meta-address on Ethereum has the following format:
 
 ```
-st:eth:0x<spendingKey><viewingKey>
+st:eth:0x<spendingPubKey><viewingPubKey>
 ``` 
 
-Stealth meta-addresses may be managed by the user and/or registered within a publicly available `Registry` contract, as delineated in [ERC-6538](./eip-6538). This provides users with a centralized location for identifying stealth meta-addresses associated with other individuals while simultaneously enabling recipients to express their openness to engage via stealth addresses.
+Stealth meta-addresses may be managed by the user and/or registered within a publicly available `Registry` contract, as delineated in [ERC-6538](./eip-6538.md). This provides users with a centralized location for identifying stealth meta-addresses associated with other individuals while simultaneously enabling recipients to express their openness to engage via stealth addresses.
 
 *Notably, the address format is used only to differentiate stealth addresses from standard addresses, as the prefix is removed before performing any computations on the stealth meta-address.*
 
 ---
 
 ### Initial Implementation of SECP256k1 with View Tags
 
-This ERC provides a foundation that is not tied to any specific cryptographic system through the `IERC5564Announcer` contract. In addition, it introduces the first implementation of a [stealth address scheme](../assets/eip-5564/scheme_ids.md) that utilizes the SECP256k1 elliptic curve and view tags. The SECP256k1 elliptic curve is defined with the equation $y^2 = x^3 + 7 \pmod{p}$, where $p = 2^{256} - 2^{32} - 977$.
+This ERC provides a foundation that is not tied to any specific cryptographic system through the `IERC5564Announcer` contract. In addition, it introduces the first implementation of a stealth address scheme that utilizes the SECP256k1 elliptic curve and view tags. The SECP256k1 elliptic curve is defined with the equation $y^2 = x^3 + 7 \pmod{p}$, where $p = 2^{256} - 2^{32} - 977$.
 
 The following reference is divided into three sections:
 
@@ -252,15 +252,19 @@ The stealth address specification standardizes a protocol for generating and loc
 
 The authors recognize the trade-off between on- and off-chain efficiency. Although incorporating a Monero-like view tags mechanism enables recipients to parse announcements more efficiently, it adds complexity to the announcement event.
 
-The recipient's address and the `viewTag` MUST be included in the announcement event, allowing users to quickly verify ownership without querying the chain for positive account balances.
+The recipient's address and the `viewTag` must be included in the announcement event, allowing users to quickly verify ownership without querying the chain for positive account balances.
 
 ## Backwards Compatibility
 
 This ERC is fully backward compatible.
 
+### Deployment Method
+
+The `ERC5564Announcer` contract is deployed at `0x55649E01B5Df198D18D95b5cc5051630cfD45564` using `CREATE2` via the deterministic deployer at `0x4e59b44847b379578588920ca78fbf26c0b4956c` with a salt of `0xd0103a290d760f027c9ca72675f5121d725397fb2f618f05b6c44958b25b4447`.
+
 ## Reference Implementation
 
-You can find the implementation of the ERC above in the Specification section.
+You can find the implementation of the `ERC5564Announcer` contract [here](../assets/eip-5564/contracts/ERC5564Announcer.sol) and the interface `IERC5564Announcer.sol` [here](../assets/eip-5564/contracts/interfaces/IERC5564Announcer.sol).
 
 ## Security Considerations
 

assets/erc-5564/contracts/ERC5564Announcer.sol

@@ -0,0 +1,43 @@
+// SPDX-License-Identifier: CC0-1.0
+pragma solidity 0.8.23;
+
+/// @notice `ERC5564Announcer` contract to emit an `Announcement` event to broadcast information
+/// about a transaction involving a stealth address. See
+/// [ERC-5564](https://eips.ethereum.org/EIPS/eip-5564) to learn more.
+contract ERC5564Announcer {
+  /// @notice Emitted when something is sent to a stealth address.
+  /// @param schemeId Identifier corresponding to the applied stealth address scheme, e.g. 1 for
+  /// secp256k1, as specified in ERC-5564.
+  /// @param stealthAddress The computed stealth address for the recipient.
+  /// @param caller The caller of the `announce` function that emitted this event.
+  /// @param ephemeralPubKey Ephemeral public key used by the sender to derive the `stealthAddress`.
+  /// @param metadata Arbitrary data to emit with the event. The first byte MUST be the view tag.
+  /// @dev The remaining metadata can be used by the senders however they like. See
+  /// [ERC-5564](https://eips.ethereum.org/EIPS/eip-5564) for recommendations on how to structure
+  /// this metadata.
+  event Announcement(
+    uint256 indexed schemeId,
+    address indexed stealthAddress,
+    address indexed caller,
+    bytes ephemeralPubKey,
+    bytes metadata
+  );
+
+  /// @notice Called by integrators to emit an `Announcement` event.
+  /// @param schemeId Identifier corresponding to the applied stealth address scheme, e.g. 1 for
+  /// secp256k1, as specified in ERC-5564.
+  /// @param stealthAddress The computed stealth address for the recipient.
+  /// @param ephemeralPubKey Ephemeral public key used by the sender.
+  /// @param metadata Arbitrary data to emit with the event. The first byte MUST be the view tag.
+  /// @dev The remaining metadata can be used by the senders however they like. See
+  /// [ERC-5564](https://eips.ethereum.org/EIPS/eip-5564) for recommendations on how to structure
+  /// this metadata.
+  function announce(
+    uint256 schemeId,
+    address stealthAddress,
+    bytes memory ephemeralPubKey,
+    bytes memory metadata
+  ) external {
+    emit Announcement(schemeId, stealthAddress, msg.sender, ephemeralPubKey, metadata);
+  }
+}

assets/erc-5564/contracts/interfaces/IERC5564Announcer.sol

@@ -0,0 +1,41 @@
+// SPDX-License-Identifier: CC0-1.0
+pragma solidity 0.8.23;
+
+/// @notice Interface for calling the `ERC5564Announcer` contract, which emits an `Announcement`
+/// event to broadcast information about a transaction involving a stealth address. See
+/// [ERC-5564](https://eips.ethereum.org/EIPS/eip-5564) to learn more.
+interface IERC5564Announcer {
+  /// @notice Emitted when something is sent to a stealth address.
+  /// @param schemeId Identifier corresponding to the applied stealth address scheme, e.g. 1 for
+  /// secp256k1, as specified in ERC-5564.
+  /// @param stealthAddress The computed stealth address for the recipient.
+  /// @param caller The caller of the `announce` function that emitted this event.
+  /// @param ephemeralPubKey Ephemeral public key used by the sender to derive the `stealthAddress`.
+  /// @param metadata Arbitrary data to emit with the event. The first byte MUST be the view tag.
+  /// @dev The remaining metadata can be used by the senders however they like. See
+  /// [ERC-5564](https://eips.ethereum.org/EIPS/eip-5564) for recommendations on how to structure
+  /// this metadata.
+  event Announcement(
+    uint256 indexed schemeId,
+    address indexed stealthAddress,
+    address indexed caller,
+    bytes ephemeralPubKey,
+    bytes metadata
+  );
+
+  /// @notice Called by integrators to emit an `Announcement` event.
+  /// @param schemeId Identifier corresponding to the applied stealth address scheme, e.g. 1 for
+  /// secp256k1, as specified in ERC-5564.
+  /// @param stealthAddress The computed stealth address for the recipient.
+  /// @param ephemeralPubKey Ephemeral public key used by the sender.
+  /// @param metadata Arbitrary data to emit with the event. The first byte MUST be the view tag.
+  /// @dev The remaining metadata can be used by the senders however they like. See
+  /// [ERC-5564](https://eips.ethereum.org/EIPS/eip-5564) for recommendations on how to structure
+  /// this metadata.
+  function announce(
+    uint256 schemeId,
+    address stealthAddress,
+    bytes memory ephemeralPubKey,
+    bytes memory metadata
+  ) external;
+}