0xnirlin - abi.encodePacked may get removed in solidity version 0.9.0

[sherlock-admin]

0xnirlin

medium

abi.encodePacked may get removed in solidity version 0.9.0

Summary

Protocol is using abi.encodePacked is being used in two contracts which is not recommended to be used due to hash collisions and also may get deprecated in future.

Vulnerability Detail

At following places protocol is using abi.encodePacked:
https://github.com/sherlock-audit/2023-04-footium/blob/main/footium-eth-shareable/contracts/FootiumPrizeDistributor.sol#L153-L161
https://github.com/sherlock-audit/2023-04-footium/blob/main/footium-eth-shareable/contracts/FootiumPrizeDistributor.sol#L116-L122
https://github.com/sherlock-audit/2023-04-footium/blob/main/footium-eth-shareable/contracts/FootiumAcademy.sol#L235-L241

which is not recommended to be used due to hash collision and may also get deprecated in 0.9.0 version of solidity, check following issue in solidity repo:
ethereum/solidity#11593

Impact

Can lead to unexpected results.

Code Snippet

https://github.com/sherlock-audit/2023-04-footium/blob/main/footium-eth-shareable/contracts/FootiumPrizeDistributor.sol#L153-L161
https://github.com/sherlock-audit/2023-04-footium/blob/main/footium-eth-shareable/contracts/FootiumPrizeDistributor.sol#L116-L122
https://github.com/sherlock-audit/2023-04-footium/blob/main/footium-eth-shareable/contracts/FootiumAcademy.sol#L235-L241

Tool used

Manual Review

Recommendation

use abi.encode or use bytes.concat