Which of the following are effective countermeasures to protect critical information? Select all that apply.

The correct answer is based on the idea that specific measures can be implemented to secure critical information effectively. Encryption and shredding are strong countermeasures because they directly address the protection of sensitive data.

Encryption transforms data into a coded format, making it unreadable without the proper decryption key. This ensures that even if unauthorized individuals access the data, they cannot interpret it without the necessary authorization. Shredding physical documents ensures that sensitive information cannot be reconstructed, thereby protecting against unintended disclosure, especially during disposal.

In contrast, options such as verbal communication and public announcements do not serve as protective measures for critical information. Verbal communication can easily be overheard, leading to unintentional leaks of sensitive information. Public announcements could inadvertently disclose classified information to a wide audience, particularly if the information is not intended for public consumption. Ignoring leaks undermines the entire concept of information security; it fails to address the risk and allows vulnerabilities to persist without any mitigation efforts.

In summary, encryption and shredding are effective countermeasures because they both secure sensitive information from unauthorized access and prevent information leakage during physical disposal, while the other options do not contribute to safeguarding critical information.