Definition
Access control in blockchain is a permissioning mechanism that restricts which accounts, contracts, or entities are authorized to invoke specific functions or modify particular state variables. It typically relies on on-chain checks of identities, roles, or ownership flags to determine whether an attempted action is allowed, thereby enforcing predefined authorization rules at the protocol or smart contract level.
In Simple Terms
Access control is a way to decide who is allowed to do what inside a blockchain system or smart contract. It sets rules that say which addresses or roles are permitted to call certain functions or change certain data, and blocks actions that do not meet those rules.
Context and Usage
Access control is commonly discussed in the context of smart contract design, security reviews, and formal verification of contract behavior. It is a central topic when defining administrative privileges, upgrade permissions, and restricted operations within EVM-based environments and other blockchain platforms. Access control considerations frequently appear in discussions of contract vulnerabilities, security patterns, and permissioned components of decentralized applications.