Which IFF mode is specifically used for military identification purposes?

The correct response is Mode 4, which is the Identification Friend or Foe (IFF) mode specifically designated for military use. Mode 4 is a secure, encrypted system designed to help identify military aircraft and other assets as friendly forces, thus enhancing situational awareness and preventing friendly fire incidents. It employs cryptographic methods to ensure that only authorized users can generate the appropriate responses, making it a critical component of military operations.

In contrast, the other modes have different primary uses. Mode 1 is typically used for general military operations, but it does not offer the same level of security as Mode 4. Mode 3 is commonly used for civil air traffic control, allowing air traffic controllers to identify aircraft in controlled airspaces. Mode C is used primarily for altitude reporting and civilian aircraft identification, providing data to air traffic control but lacking the security features inherent to military operations.

Thus, Mode 4 is the only IFF mode specifically designed with military needs in mind, ensuring a higher level of protection and reliability in identifying friendly forces.