Prefer abi.encode over abi.encodePacked

[code423n4]

Handle

t11s

Vulnerability details

Impact

Use of abi.encodePacked in PositionKey is safe, but unnecessary and not recommended. abi.encodePacked can result in hash collisions when used with two dynamic arguments (string/bytes). PositionKey does not use any dynamic types, but for maximum safety against future mistakes, using abi.encode is recommended.

There is also discussion of removing abi.encodePacked from future versions of Solidity (ethereum/solidity#11593), so using abi.encode now will ensure compatibility in the future.

Proof of Concept

https://github.com/code-423n4/2021-09-wildcredit/blob/edfc97a8b75bb290a7f7f61cda62d586ed42c73e/contracts/external/PositionKey.sol#L11

Recommended Mitigation Steps

Use abi.encode instead.

[talegift]

This was taken from the Uniswap repo so don't want to modify this.

[ghoul-sol]

on second look, I'll keep this as best practice