Confidentiality is an ethical principle associated with several professions (e.g., medicine, law, religion, professional psychology, translation and journalism). In ethics, and (in some places) in law and alternative forms of legal dispute resolution such as mediation, some types of communication between a person and one of these professionals are “privileged” and may not be discussed or divulged to third parties. In those jurisdictions in which the law makes provision for such confidentiality, there are usually penalties for its violation.
Confidentiality has also been defined by the International Organization for Standardization (ISO) in ISO-17799  as “ensuring that information is accessible only to those authorized to have access” and is one of the cornerstones of information security. Confidentiality is one of the design goals for many cryptosystems, made possible in practice by the techniques of modern cryptography.
Confidentiality of information, enforced in an adaptation of the military’s classic “need to know” principle, forms the cornerstone of information security in today’s corporations.
The so called ‘confidentiality bubble’ restricts information flows, with both positive and negative consequences.