Information hiding refers to a programming design process where the details of an object or a function are hidden.

There are several purposes for information hiding. First, not all details are necessary for the operation of a program. Details concerning implementations of program tasks can be hidden without affecting the performance of the program. Conversely, however, providing all the details of implementation and other functions definitely does increase the complexity of operating a program. Thus, information hiding reduces the complexity of an operational program. This is beneficial for the user, especially those for whom the mechanics of program operation are arcane. As with driving a car, one does not need to know everything about a computer program in order to use it.

Second, information hiding facilitates a process called encapsulation—combining elements to create a larger element. For example, a programming procedure is a form of encapsulation because it combines a series of instructions. Encapsulation allows a computer programmer to focus on the larger element without having to contend with its myriad unnecessary details. The object-oriented programming relies on encapsulation. Thus, information hiding is also an important facet of this type of programming.

Finally, information hiding can be used to hide programming details that otherwise might be altered. If unseen, information is less likely to be intentionally or unintentionally altered.