A duty of confidentiality is an obligation imposed on someone by a relationship which may either be law recognized, standards of a certain profession or provisions of a binding contract. This is a special status that prevents disclosure of private information.
These types of relationships include an attorney-client, physician-patient or priest-penitent relationships. Here, the one imposing the obligation of confidentiality is the client not the attorney, the patient and not the physician and the penitent not the priest. This means that the one being imposed on is not allowed to disclose any information to a third party. The most unaltered relationship that gives rise to a duty of confidentiality is the attorney-client relationship. Any conversation or communication made by this relationship is considered as privileged. However the relationship must be established before raising the conversation as privileged. Some clients only seek for advice from the attorney which may not be a formal attorney-client relationship although the attorney is still bound to keep the conversations private.
The privilege belongs to the client therefore he has the only right to waive that privilege if he sees it so. The client may waive the privilege once he discloses the confidential information to another party aside from the attorney. The attorney however may only disclose information with the consent of the client. The duty of confidentiality may also be expressed in a contractual basis. This usually happens in a company and everyone involved in all their business transactions including employees. If they want to retain certain information to within their company, the employees will be required to sign a contract stating that they are not to disclose any valuable information outside the corporation.