BEP-410: Add Agent for Validators (#410)

BEPs/BEP-410.md

@@ -0,0 +1,106 @@
+<pre>
+  BEP: 410
+  Title: Add Agent for Validators
+  Status: Draft
+  Type: Standards
+  Created: 2024-07-15
+</pre>
+
+# BEP-410: Add Agent for Validators
+
+- [BEP-410: Add Agent for Validators](https://github.com/bnb-chain/BEPs/pull/410)
+    - [1. Summary](#1-summary)
+    - [2. Abstract](#2-abstract)
+    - [3. Motivation](#3-motivation)
+    - [4. Specification](#4-specification)
+    - [5. Reference Implementations](#5-reference-implementations)
+    - [6. License](#6-license)
+
+
+## 1. Summary
+
+This BEP attempts to enhance the security of validator account management through account isolation by delegating some of the validator operator's permissions to other accounts.
+
+## 2. Abstract
+
+Currently, validators need to manage the operator key, consensus key, and vote key. Among these, the operator key is used for operating a validator, including creating a validator, editing the information of a validator, and undelegating. 
+When creating a validator, the operator key is also used for self-delegating with more than 2001 BNB. Since the operator key holds a large amount of staking, it is not suitable for daily management of the validator. 
+Therefore, we have introduced a new `updateAgent` interface in the system contract. Through this interface, the operator can delegate another account to manage the validator.
+
+## 3. Motivation
+
+Before this BEP, the consensus address, commission rate, validator description and vote address can only be changed by the operator which also manages staking for the validator.
+To reduce the usage of operator key and improve the security of operator key management, validators can set an agent to help them to take on the mentioned tasks below.
+
+## 4. Specification
+### Data Structure
+The current [`Validator`](https://github.com/bnb-chain/bsc-genesis-contract/blob/2dbebb57a0d436d6a30b78c1f123395035249035/contracts/BC_fusion/StakeHub.sol#L154) struct is as follows.
+```solidity
+struct Validator {
+    address consensusAddress;
+    address operatorAddress;
+    address creditContract;
+    uint256 createdTime;
+    bytes voteAddress;
+    Commission commission;
+    Description description;
+    bool jailed;
+    uint256 jailUntil;
+    uint256 updateTime;
+    uint256[20] __reservedSlots;
+} 
+```
+
+
+The new `Validator` struct is as follows. This BEP adds a new field `agent` and reduce a slot of `__reservedSlots` in the `Validator` struct to keep
+the slot layer compatibility of upgradeable contracts.
+
+```solidity
+struct Validator {
+    address consensusAddress;
+    address operatorAddress;
+    address creditContract;
+    uint256 createdTime;
+    bytes voteAddress;
+    Description description;
+    Commission commission;
+    bool jailed;
+    uint256 jailUntil;
+    uint256 updateTime;
+    // The agent can perform transactions on behalf of the operatorAddress in certain scenarios.
+    address agent;
+    uint256[19] __reservedSlots;
+} 
+```
+
+### Interface
+
+The validator operator can set the agent address for the validator by calling the following function. 
+The `newAgent` cannot be any operator address or any existing agent.
+Each validator can only have one agent assigned at a time. Updating to a new agent will override the previous one.
+
+```solidity
+    function updateAgent(address newAgent) external validatorExist(msg.sender);
+```
+
+### Agent Permission
+
+The agent is allowed to edit the consensus address, commission rate, description and vote address of the validator.
+The methods that can be accessed are as follows:
+
+```solidity
+    function editConsensusAddress(address newConsensusAddress) external;
+    function editCommissionRate(uint64 commissionRate) external;
+    function editDescription(Description memory description) external;
+    function editVoteAddress(bytes calldata newVoteAddress, bytes calldata blsProof) external;
+```
+
+It is notable that even after the agent is set, the operator retains the ability to edit the information listed below.
+
+## 5. Reference Implementations
+See https://github.com/bnb-chain/bsc-genesis-contract/pull/568.
+
+
+## 6. License
+
+The content is licensed under [CC0](https://creativecommons.org/publicdomain/zero/1.0/).

README.md

@@ -75,6 +75,7 @@ Here is the list of subjects of BEPs:
 | [BEP-366](./BEPs/BEP-366.md) | PGreenfield Atomic Object Update                           | Standards | Candidate |
 | [BEP-402](./BEPs/BEP-402.md) | Complete Missing Fields in Block Header to Generate Signature          | Standards | Candidate |
 | [BEP-404](./BEPs/BEP-404.md) | Clear Miner History when Switching Validator Set          | Standards | Candidate |
+| [BEP-410](./BEPs/BEP-410.md) | Add Agent for Validators          | Standards | Draft     |