Confidentiality is the principle that information and information systems are only available to authorized users, that that they are only used for authorized purposes, and they are only accessed in an authorized manner. Confidentiality also determines information disclosure authority and conditions; unauthorized disclosure or use of confidential information could be harmful or prejudicial. The ‘official’ definition of confidentiality is: Preserving authorized restrictions on information access and disclosure, including means for protecting personal privacy and proprietary information. [44 U.S.C., SEC. 3542]