Confidentiality

Confidentiality has been defined by the International Standards Organization (ISO) 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 also refers to an ethical principle associated with several professions (eg, medicine, law, religion, journalism, ...). In ethics, and (in some places) in law, 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.