How should classified information be protected when shared in electronic format?

Marking and encrypting classified information according to established policies is essential to ensure the security and integrity of this sensitive data when shared in electronic format. Proper marking alerts recipients to the classification level and handling requirements, which is crucial for maintaining the security protocols associated with classified material.

Encryption adds an additional layer of security, rendering the information unreadable to unauthorized individuals during transmission and storage. Following policies is vital because they outline specific requirements for both marking and encryption based on the level of classification, the sensitivity of the data, and the environment in which it will be shared. Adhering to these protocols minimizes the risk of unauthorized access and data breaches, which can have serious implications for national security.

Other options neglect either the comprehensive measures needed for proper protection or imply a level of security that could lead to vulnerabilities. For example, encrypting without marking fails to communicate the information's sensitivity to recipients, while relying solely on secure email systems ignores potential threats that could still capture unencrypted data. Therefore, marking and encrypting in accordance with policies provides the most robust approach for sharing classified information electronically.