There are too many aspects of privacy to capture in a single framework. A few examples will illustrate its multi-dimensional nature.
Human individuals are, first and foremost, interacting and communicating bodies. And the fact that we cover certain parts of our bodies in public, and generally do not perform certain bodily functions in the public gaze is, perhaps, the beginning of privacy. A natural extension of this in most societies is the physical and social privacy afforded by the family (or the individual's) home.
Psychological privacy is a difficult notion to pin down. Some psychologists postulate privacy as a universal need. There are recent claims that when the private realm of a child is not respected non-compliant behavior and even depression ensues.
But there is disagreement about these issues amongst researchers. Alan Kazdin of Yale University (see link above) claims that both children and adults will willingly accept intrusion upon their privacy and autonomy so long as it is done in such a way as to maintain a self-perception of autonomy. In effect, he rejects the need to postulate a protected, private realm in order to explain behavior.
Cultural diversity, which can be extreme in these matters, further complicates the picture. Literacy and other cultural and technological innovations are hugely significant in creating scope for individual activity which does not exist in, for example, traditional hunter-gatherer societies. But even in technologically advanced societies there are marked differences in the degree to which privacy and individual freedom are valued and incorporated into social behavior and thinking.
If the psychological dimensions of privacy are confusing and culturally diverse, there is at least a degree of clarity and consensus on the legal front. Most legal attention is accorded to professional, financial and bureaucratic contexts. Professional confidentiality increasingly merges into the realm of personal data and information which is the subject of extensive privacy legislation in the developed world.
The individual, through his or her multiple connections (as client, patient, member, license-holder, etc.) with multiple professionals, businesses, government departments and associations, is the center of a complex web of (often interconnected) electronically stored information covering identity, medical, legal and financial matters, commercial transactions and a vast array of professional and leisure activities. Clearly, access to and control of this information must be tightly restricted if the law-abiding individual is not to be subject to very serious threats to his or her autonomy and financial well-being. This may be understood in terms of the individual possessing - by virtue of the operation of conventions and laws relating, for example, to privacy and property - certain negative freedoms (freedom from being dispossessed etc.).
It is undeniable that, at a practical level, an individual's freedom and welfare depend upon the protection of certain kinds of information, and, in this sense, privacy may be seen to underlie human freedom.
There is no single right to privacy. Rather, there is range of privacy conventions, implicit rules and laws, many of which imply or confer rights (though generally not absolute rights); and these conventions and laws help to create a space - or rather a series of spaces - for the individual to operate unencumbered.
A mundane view of privacy, a modest view of freedom, but none the worse for that.