Identification Friend or Foe has run on Mode 4 since the 1960s. The U.S. Department of Defense AIMS program office ceased generation of Mode 4 Crypto keys in June 2020, and has mandated the conversion for all systems to Mode 5.
Mode 5 significantly improves the ability to identify and track friendly aircraft, providing increased situational awareness to command and control and Combat-ID functions. Mode 5 improvements include new cryptography, stronger security features, modern signal modulation techniques and greater data content. The increased data capacity enables encrypted transmission and supports new data formats, including National Origin codes and Platform Identification Numbers.
Mode 5 also includes lethal interrogations designed to prevent fratricide by providing a final challenge to a targeted platform prior to weapons engagement. Lethal interrogation formats elicit a Mode 5 response even when the platform is flying radio silent or "EMCOM," short for emission control.
At Raytheon Intelligence & Space, we build the most advanced IFF transponders and interrogators, and we also work with our customers to ensure that the systems are properly integrated. This includes analysis and planning, platform design and development, and integration and test support