informationshiding

Information hiding is the practice of concealing internal details and data structures within a system, exposing only what is necessary through well-defined interfaces. The term is central to software engineering and is often associated with the information hiding principle introduced by David L. Parnas in the early 1970s. The idea is to separate the visible behavior of a component from its implementation, so other parts of the system depend on a stable interface rather than on changing internals.

In practice, information hiding is implemented through encapsulation, data abstraction, and access controls. Data members may be declared private or protected, and access is provided only via public methods. Interfaces serve as contracts; internal algorithms and storage formats can be changed without affecting clients as long as the interface remains the same. This reduces coupling and makes maintenance and evolution easier.

Benefits include easier maintenance, safer refactoring, and greater modularity, which supports reuse and parallel development. However, overzealous hiding can hinder debugging and performance, and some abstractions may leak or become difficult to use—a phenomenon known as leaky abstractions. Effective information hiding requires clear boundaries, documentation, and thoughtful interface design.

In information security and privacy, information hiding refers to minimizing the extent to which sensitive details are exposed to users or external systems. This can involve data minimization, strict access control, and careful management of API surface area. It is complementary to cryptographic protections and auditing rather than a stand-alone security measure.

See also encapsulation, modularity, abstraction, API design, information security.