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.

Journalistic confidentiality

Journalists often recognize four levels of confidentiality with news sources. They are:

*On the record - Information provided "on the record" may be quoted and attributed directly to the source. For instance, "Mr. Jones, a metropolitan police captain, said..."

*On background - Information provided "on background" may be attributed to a person's position. For instance, "A metropolitan police worker speaking on condition of anonymity said..."

*Deep background - Information provided "on deep background" may be included in the article, but not clearly attributed. For instance, "A source familiar with the investigation indicated..." or simply "there are suspicions that..."

*Off the record - Information provided "off the record" may not be used in any way in news articles, and because of that journalists are frequently wary of accepting such information. It is sometimes used to point journalists in the direction of other sources or simply to speak frankly on a personal level.

See also: Secrecy