Which of the following is NOT included as one of the six aids to defend against analysis?

• A. Good procedures
• B. Callsign omission
• C. Authorized code words
• D. Encryption

Answer: (D)

Defending against analysis focuses on reducing what an observer can learn from the transmission patterns and metadata. Good procedures create a stable, predictable workflow that minimizes accidental disclosures and patterns that could be exploited. Omitting the callsign and using authorized code words further limit how much identifying or contextual information an outsider can associate with the transmission, without changing the actual essential content. Encryption, while it hides content, is often restricted or prohibited in many radio services, so it isn’t counted among the standard aids used to defend against analysis. For that reason, encryption is not considered one of the six aids in this context.