# Storage variables can be cached to save gas Low/Info · Three Sigma · Cross-chain bridge · 15th July, 2024 Finding 3S-OB-N03 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 Reading/writing from the same storage variable more than once should be avoided to save gas. ### Recommendation BRC20Factory::burn() can cache the [fee](https://github.com/orangecryptohq/orange-bridge-contract/blob/main/src/BRC20Factory.sol#L111) (read twice). Vault::deposit() cache the [fee](https://github.com/orangecryptohq/orange-bridge-contract/blob/main/src/Vault.sol#L84-L89) (read thrice). Vault::acceptAdmin() can cache the [pendingAdmin](https://github.com/orangecryptohq/orange-bridge-contract/blob/main/src/Vault.sol#L153-L156) (read 4 times). Vault::withdraw() can cache [signers.length](https://github.com/orangecryptohq/orange-bridge-contract/blob/main/src/Vault.sol#L115) (read number of signers times). ### Status Addressed in [#68ce26f](https://github.com/orangecryptohq/orange-bridge-contract/commit/68ce26ff8cacbbd39efae4662c2fdde12d16671c9). --- Related findings: - [Storage variables should be cached whenever possible to save gas](https://0xsimao.com/findings/glacier-storage-cached-whenever-gas): Glacier - [Storage variables can be cached to save gas](https://0xsimao.com/findings/mitosis-storage-variables-cached-gas): Mitosis - [Variables should be cached to memory to save gas](https://0xsimao.com/findings/metazero-ii-variables-cached-memory-gas): MetaZero Staking - [genesisLimit can be placed as constant variables to save gas.](https://0xsimao.com/findings/metazero-i-genesis-placed-constant-gas): MetaZero Omnichain NFTs