It is a contract through which the parties agree not to disclose information covered by the agreement. An NDA creates a confidential relationship between the parties, typically to protect any type of confidential and proprietary information or trade secrets. A non-disclosure agreement (NDA), also known as a confidentiality agreement (CA), confidential disclosure agreement (CDA), proprietary information agreement (PIA) or secrecy agreement (SA), is a legal contract between at least two parties that outlines confidential material, knowledge, or information that the parties wish to share with one another for certain purposes but wish to restrict access to. Doctor-patient confidentiality (physician-patient privilege), attorney-client privilege, priest-penitent privilege, bank–client confidentiality, and kickback agreements are examples, often not enshrined in a written contract between the parties.