In Smalltalk, the only way how to communicate to objects is by sending messages. The way how they react on the messages is full the responsibility of objects, and they can refuse them. This decision is strictly late-bound because all message passing in Smalltalk is late-bound. You may say that all the methods in Smalltalk are "public", but it is not the very same meaning as in other languages.

The objects store the state in instance variables. You cannot access the instance variables of objects from outside of the object. All instance variables are "protected" in the terminology of C++.