In frequency-hopping field radios, how are hop patterns and keys managed?

• A. Radios synchronize hop patterns and use cryptographic keys; keys are loaded securely, stored securely, rotated per policy, and protected from disclosure.
• B. Hop patterns are chosen randomly without synchronization.
• C. Keys are rotated daily but hop patterns are static.
• D. Hopping is disabled to improve reliability.

Answer: (A)

Frequency-hopping radios rely on both ends following the same hop pattern in lockstep while protecting the conversation with cryptographic keys. The hop pattern must be synchronized so the transmitter and receiver jump to the same sequence of frequencies at the same times, otherwise the link would be lost as the two radios would be listening on different channels. At the same time, the cryptographic keys used to protect the transmitted data must be handled securely: loaded into the radios through secure procedures, stored in secure memory, rotated according to policy to limit exposure if a key is compromised, and protected from disclosure to prevent adversaries from decrypting or predicting the hops. This combination ensures both reliability—through synchronized hopping—and confidentiality and resilience—through proper key management. The other approaches fail because unsynchronized or random hopping breaks the link, static key usage with changing hops reduces security effectiveness, and turning hopping off eliminates the essential anti-jamming and frequency-agility benefits.