What is required for secure email communication when reporting a cyber incident?

In the context of secure email communication for reporting a cyber incident, a digital signature is crucial because it guarantees the authenticity and integrity of the message. When an email contains a digital signature, recipients can verify that the sender is indeed who they claim to be and that the content of the email has not been tampered with during transmission. This is essential when dealing with sensitive cyber incident information, as it helps prevent impersonation and ensures the reliability of the information being shared.

Although encryption of all data, two-factor authentication, and the use of a secure server enhance overall security, they do not specifically address the verification of the sender’s identity and the integrity of the message in the same way that a digital signature does. Encryption ensures confidentiality by protecting the content from unauthorized access, while two-factor authentication adds an extra layer of security at the account access level. A secure server mitigates risks associated with where the communication is hosted, but does not validate the content's authenticity or the sender's identity. Thus, in the context of reporting cyber incidents through email, the most pertinent requirement is the presence of a digital signature.