Data Classification is the method used by organizations to determine the type of information and the risk to the organization if the information were mishandled, shared to personnel that did not have a requirement to know the information, or if alterations were made could have a drastic impact on the company. There are public and private implementations of the classification, such as publicly releasable, internal or proprietary such as a, trade secret, or within national security of confidential, secret, top secret. In addition to classification of the data, there is also the concept of handling instructions for the information, referred to as handling caveats and limited Dissemination Controls. Some labeled as CUI information might be for internal personnel and not contractors, or United States Employees, and no foreign access.
URL: Data Classification Guidance
CUI Registry: Limited Dissemination Controls | National Archives