# Domain separator calculation is not fork safe Medium · Three Sigma · Cross-chain bridge · 15th July, 2024 Finding 3S-OB-L07 of the Orange Bridge security review. - Protocol: https://www.orangeweb3.com/ - Report: /reports/orange - Source: https://cdn.sanity.io/files/qoqld077/production/686ad4e1d5035d69002f5f97e281e3c5a8b7ce00.pdf --- ### Description The domain separator is cached in the constructor of the [contracts](https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/utils/cryptography/EIP712.sol#L80-L86), which could lead to signature signing softwares in case of a hard fork. When a hard fork happens, block.chainid changes, which affects the domain separator, but as it is only computed in the constructor, it will be forever incorrect. Messages can still be signed but EIP712 will be broken. ### Recommendation The EIP712 contract from OpenZeppelin handles this by caching the original domain separator and recomputing it if block.chainid has changed. ### Status Addressed in [#143cee8](https://github.com/orangecryptohq/orange-bridge-contract/commit/143cee88bcb606bb7c898943e7d3c6f15091eb93).