Staking Contract

Basic staking contract where:

• Users stake an ERC20.
• Owner funds the staking contract with ETH to be distributed.
• Users can claim ETH in relation the amount and time staked.

Improvements

1. Allow anyone to fund the contract to increase reward pool:
   • Remove the onlyOwner modifier from fundETHRewards and receive functions.
2. Allow users to withdraw partial rewards:
   • if rewards > address(this).balance the claimRewards function reverts
3. Use SafeERC20 library from OpenZeppelin for safer token transfers:
   • SafeERC20 wraps the standard ERC20 functions (transfer, transferFrom, etc.) to handle the low-level call to the token contract
4. Improve coverage / add invariant testing
5. Implement a more sophisticated reward calculation that takes into account different staking periods and reward multipliers:
   • the current reward calculation is simple and linear, based solely on the amount staked and the time it has been staked
   • a more sophisticated calculation can involve different reward rates for different staking periods. For example, longer staking periods could have higher reward rates to incentivize long-term staking
   • this can be achieved by defining multiple reward tiers, where each tier corresponds to a different staking period and has a different reward rate.
6. Integrate ERC-4626 Tokenized Vault standard:
   • assets provided to the vault can be utilized in other yield-generating protocols (e.g. lending platforms, yield farms) to earn additional rewards
   • tokenized shares minted to users can be utilized in other DeFi protocols, providing additional yield opportunities or serving as collateral
   • leverage the security audits and community scrutiny of the ERC-4626 standard, reducing the risk of vulnerabilities

Sepolia Deployment

• MockERC20 - 0xFD97fB4e074F5B5822A0d868093E82D29429d23c
• StakingContract - 0x705b9c2aFd015B1d4fBec7D7a95eedca7b0296E9

Sepolia Interaction

• mint some MockERC20 tokens
• approve StakingContract to spend MockERC20 tokens
• stake MockERC20 tokens

WARNING:

• the contract has ~0.1ETH available for rewards
• deposit only a few tokens and see how the rewards accumulate (on stake/withdraw)
• depositing too many tokens which result in having the accruedReward > contract balance would make the claimRewards function revert (see improvement 2).