---
lip: 14
title: Ownable2Step
author:
discussions-to: https://discord.gg/E2rJPP4
status: Draft
type: LSP
created: 2022-09-23
requires: ERC173
---

## Simple Summary
<!--"If you can't explain it simply, you don't understand it well enough." Provide a simplified and layman-accessible explanation of the LIP.-->
This standard describes a modified version of [EIP173](https://github.com/ethereum/EIPs/blob/master/EIPS/eip-173.md) that uses a a 2-step process to transfer or renounce ownership of a contract, instead of instant execution.

In addition, this standard defines hooks in the form of external calls to:
- notify when the new owner of the contract should accept ownership.
- notify the previous and new owner when ownership of the contract has been fully transferred.

## Abstract
<!--A short (~200 word) description of the technical issue being addressed.-->
The particular issue that this implementation of [EIP173](https://github.com/ethereum/EIPs/blob/master/EIPS/eip-173.md) solves is the irreversible nature of transferring or renouncing ownership of a contract.

Firstly, because owning the contract allows access to sensitive methods, transferring to the wrong address or renouncing ownership of the contract by accident in a single transaction can be highly dangerous. Having those two processes work in 2 steps substantially reduces the probability of transferring or renouncing ownership of the contract by accident.

## Motivation
<!--The motivation is critical for LIPs that want to change the Ethereum protocol. It should clearly explain why the existing protocol specification is inadequate to address the problem that the LIP solves. LIP submissions without sufficient motivation may be rejected outright.-->
When ownership of a contract is transferred in a single transaction, the new owner has no choice in wanting to own the contract or not. He is forced to own the contract once the transaction has been completed.

Making transfer of ownership a two-step process enables to give a choice for the new owner in deciding if he wants to become the owner of the contract or not.

Finally, transferring ownership of the contract in a single transaction does not guarantee that the address behind the new owner (EOA or contract) is controlled. For instance, if the new owner lost its private key or if the new owner is a contract that is in a locked state.

Letting the new owner accept ownership of the contract guarantees that the contract is owned by an address (EOA or contract) that can be controlled, and that control over the contract implementing LSP14 will not be lost.

## Specification

[ERC165] interface id: `0x94be5999`

_This interface id can be used to detect Ownable2Step contracts._

### Methods

Contains the methods from:
- [ERC173](https://github.com/ethereum/EIPs/blob/master/EIPS/eip-173.md#specification) (Ownable). *See below for details*

#### owner

function owner() external view returns (address);

Returns the `address` of the current contract owner.

#### pendingOwner

function pendingOwner() external view returns (address);

Returns the `address` of the upcoming new owner that was initiated by the current owner via `transferOwnership(address)`.

*Requirements:*

- MUST be `address(0)` if no ownership transfer is in progress.
- MUST be set when transferring ownership of the contract via `transferOwnership(address)` to a new `address`.
- SHOULD be cleared once the [`pendingOwner()`](#pendingowner) has accepted ownership of the contract.

#### transferOwnership

function transferOwnership(address newOwner) external;

Sets the `newOwner` as `pendingOwner()`. To transfer ownership fully of the contract, the pending owner MUST accept ownership via the function `acceptOwnership()`.

MUST emit a [`OwnershipTransferredStarted`](#ownershiptransferstarted) event once the new owner was set as `pendingOwner()`.

*Requirements:*

- MUST only be called by the current `owner()` of the contract.
- The `newOwner` MUST NOT be the contract itself `address(this)`

#### acceptOwnership

function acceptOwnership() external;

Allows the `pendingOwner()` to become the new owner of the contract.

This function MUST be called as the second step (after `transferOwnership(address)`) by the current `pendingOwner()` to finalize the ownership transfer.

MUST emit a [`OwnershipTransferred`](https://eips.ethereum.org/EIPS/eip-173#specification) event once the new owner has claimed ownership of the contract.

*Requirements:*

- MUST only be called by the `pendingOwner()`.

#### renounceOwnership

function renounceOwnership() public;

Leaves the contract without an owner. Once ownership of the contract is renounced, it MUST NOT be possible to call the functions restricted to the owner only.

Since renouncing ownership is a sensitive operation, it SHOULD be done as a two step process by calling `renounceOwnership(..)` twice. First to initiate the process, second as a confirmation.

MUST emit a [`RenounceOwnershipInitiated`](#renounceownershipinitiated) event on the first `renounceOwnership(..)` call.
MUST emit [`OwnershipTransferred`](https://eips.ethereum.org/EIPS/eip-173#specification) event after successfully renouncing the ownership.

*Requirements:*

- MUST be called only by the `owner()` only.
- The second call MUST happen AFTER the delay of 100 blocks and within the next 100 blocks from the first `renounceOwnership(..)` call.
- If the 200 block has passed, the `renounceOwnership(..)` call phase SHOULD reset the process, and a new one will be initated.

### Events

#### OwnershipTransferStarted

event OwnershipTransferStarted(address indexed previousOwner, address indexed newOwner);

MUST be emitted when the process of transferring owhership of the contract is initiated.

_Values:_

- `previousOwner` Address of the current owner of the conract that implements LSP14.

- `newOwner` Address that will receive ownership of the contract that implemets LSP14.

#### RenounceOwnershipInitiated

event RenounceOwnershipInitiated();

MUST be emitted when the process of renouncing ownership of the contract is initiated.

### Hooks

Every contract that supports the LSP14 standard SHOULD implement these hooks:

#### _notifyUniversalReceiver

function _notifyUniversalReceiver(
    address universalReceiver,
    bytes32 typeId,
    bytes memory data
)

Calls the `universalReceiver(..)` function on the `universalReceiver` address in the following situations:

- When transferring ownership to the new owner, if the new owner address supports LSP1 InterfaceID, with the parameters below:

- `typeId`: keccak256('LSP14OwnershipTransferStarted')
- `data`: TBD

- When accepting ownership by the new owner, if the old owner address supports LSP1 InterfaceID, with the parameters below:

- `typeId`: keccak256('LSP14OwnershipTransferred_SenderNotification')
- `data`: TBD

- When accepting ownership by the new owner, if the new owner address supports LSP1 InterfaceID, with the parameters below:

- `typeId`: keccak256('LSP14OwnershipTransferred_RecipientNotification')
- `data`: TBD

## Interface Cheat Sheet

interface ILSP14  /* is ERC173 */ {
         

    event OwnershipTransferStarted(address indexed previousOwner, address indexed newOwner);
    
    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    event RenounceOwnershipInitiated();


    function owner() external view returns (address);
    
    function pendingOwner() external view returns (address);

    function transferOwnership(address newOwner) external; // onlyOwner

    function acceptOwnership() external;
    
    function renounceOwnership() external; // onlyOwner

}

## Copyright

Copyright and related rights waived via [CC0](https://creativecommons.org/publicdomain/zero/1.0/).

[ERC165]: <https://eips.ethereum.org/EIPS/eip-165>
[LSP1-UniversalReceiver]: <./LSP-1-UniversalReceiver.md>
[LSP2-ERC725YJSONSchema]: <./LSP-2-ERC725YJSONSchema.md>