The purpose of this guide is to inform a wide range of professionals working with children and families about confidentiality and privilege laws. NDAs, or non-disclosure agreements, are legally enforceable contracts that create a confidential relationship between a person who has sensitive information.Overview of NonDisclosure Agreements. Often referred to as a confidentiality agreement (CA), the NDA is the first document signed in a transaction. Disclosure agreement is a legal document used to protect confidentiality in disclosure to potential investors, creditors, clients, or suppliers. However, home sellers in Massachusetts are NOT required to fill out a seller's disclosure form. Disclosure agreement (NDA) is a contract between two parties in which one party shares confidential information and the other promises not to disclose it. A Massachusetts non-disclosure agreement (NDA) is a legal contract that safeguards confidential information shared between parties.