The doctor committed a 'breach of confidentiality'. [=the doctor told another person private information about a patient]
All medical records are treated with complete 'confidentiality'. [=are kept completely private]
Someone was leaking 'confidential' information [=telling secrets] to the press.
(..) Is everything okay? Just please feel comfortable coming to me... ...with any problems, any issues. Anything at all. You know, completely confidential. Okay? - See you tomorrow, Flynn. - See you, Jeffrey. Oh, man. Let me see it. (..)2009 TvShow: Breaking Bad Title: Peekaboo Season: 2 Episode 6