Short Answer 
Sensitive Compartmented Information (SCI) is a highly classified category of information requiring strict access controls due to national security concerns. To access SCI, individuals must have a valid security clearance and a legitimate need-to-know, and the classification is managed by specific government agencies to ensure enhanced security measures.
Step 1: Define Sensitive Compartmented Information (SCI)
Sensitive Compartmented Information (SCI) refers to highly classified information that requires strict controls due to its sensitivity and potential national security risks. Unlike regular classified information such as Top Secret or Secret, SCI necessitates additional security measures. This classification ensures that any unauthorized disclosure could significantly threaten national security.
Step 2: Understand Access Requirements
Accessing SCI is not straightforward; it requires stringent criteria. Individuals must fulfill two primary conditions: they need to possess a valid security clearance and demonstrate a legitimate need-to-know concerning the information. This means that even if someone has a security clearance, they will only gain access to SCI if it is relevant to their specific role or responsibilities.
Step 3: Recognize the Organizational Role
The designation of information as SCI is made by specific government agencies or departments, which evaluates the operational needs alongside the sensitivity of the data. These organizations implement additional security measures over traditional classifications, creating a layered approach to protect the most sensitive information from unauthorized access or exposure.