External Security Layer

Definition ∞ An external security layer refers to a separate protocol or system that augments the security properties of an underlying blockchain without altering its core design. These layers operate independently but rely on the base chain for certain guarantees, such as data availability or final settlement. Their purpose is to enhance specific aspects like transaction speed, cost efficiency, or specialized cryptographic assurances. They extend the security of the main chain to a broader range of applications.
Context ∞ The concept of external security layers is prominent in discussions about blockchain scalability and interoperability. News often covers layer-2 solutions like rollups or sidechains that function as external security layers for mainnets like Ethereum or Bitcoin. Debates center on the trade-offs between the security inheritance from the base layer and the independent security assumptions introduced by the external layer, particularly regarding their mechanisms for fraud detection or validity proofs.