I’m pretty sure it’s server
Implementation hiding i<u>s the encapsulation of method details within a class</u>. Implementation can be interpreted as those specifications which can be altered without altering the correctness of an application. Wrapping data/methods within classes (descriptions of the way all objects of this type will look/act) in combination with implementation hiding is called encapsulation. Information users need to know about behaviors should be available without dependence on implementation specifications.