A non-disclosure agreement (NDA) is a legal contract that states certain information to be confidential and the extent to which its disclosure is restricted to third parties. It can be entered into with a person or an organization.

Confidential information includes trade secrets, business plans, business methods and strategies, drawings, charts, and so on. Software programs and code are also included in the category of confidential information. Consultants and agencies are usually asked to sign one to protect trade secrets as they mostly work with multiple organizations within the same industry.