Clear DefinitionsAccess Control List (ACL) in dApps
ACLs in dApps are like a guest list at a private club, where only names on the list can enter certain rooms or access VIP areas.
ACLs provide explicit, programmable permission checks for blockchain applications.
Address-role mapping: Associates accounts with permission levels or roles.
On-chain enforcement: Smart contract code checks ACL before executing protected functions.
Dynamic updates: Roles can be granted or revoked via governance or admin calls.
Gas considerations: ACL checks incur computation and storage costs on each call.
A DAO contract uses an ACL mapping to allow only addresses with the "PROPOSER_ROLE" to submit governance proposals, enforced by OpenZeppelin’s AccessControl library.
In Solidity, ACLs are implemented via `mapping(address => bool)` or `mapping(bytes32 => mapping(address => bool))`. Roles are represented by `bytes32` identifiers; `hasRole()` modifiers guard functions. Granting/revoking emits `RoleGranted`/`RoleRevoked` events. ACL storage resides in the contract’s slot, and lookups cost ~2100 gas per check. Complex systems may use on‑chain Merkle roots to compress large ACLs.
Incorrect role assignments or missing revoke logic can lock out administrators or grant unintended privileges. Always include an emergency pause or timelock.
On‑chain ACLs increase transparency but incur gas costs; off‑chain ACLs may be cheaper but less tamper‑resistant.