Privacy is one of the four most important real objectives in information security. Characteristics of a system to permit and to unauthorized subjects, the access to these objects refuse entitled subjects the access to certain objects (frequently electronic or physical documents).
Minutes for the keeping of the privacy are IPsec.
By privacy one, that information is accessible for authorized one only, understands unauthorized ones against it no entrance to the information has. So for example, only the transmitter and receiver can read a message in the plain language