Which programming concept helps ensure an object's data security by bundling data and methods?

The concept that ensures an object's data security by bundling data and methods is encapsulation. Encapsulation is a key principle of object-oriented programming that involves wrapping the data (attributes) and the methods (functions) that operate on the data into a single unit, usually known as a class. This mechanism protects the internal state of the object from unauthorized access and modification by restricting direct access to some of the object's components.

Through encapsulation, developers can control how the data can be accessed or modified, typically by providing public methods (getters and setters) for safe interaction with the object's properties. This means that even if the internal representation of the data changes, the interface offered by the public methods remains intact, allowing for safe and predictable interactions.

Additionally, encapsulation promotes a clear separation between implementation and interface, enhancing code maintainability and flexibility. It allows developers to change the internal workings of a class without affecting other parts of the program that rely on its public methods, thereby reducing complexity and improving data integrity.