The IFF transponder, short for Identification Friend or Foe transponder, was a core identity system integrated into the structure of all ships throughout the galaxy, at least as early as the era of the Galactic Empire, according to time records. This system transmitted the ship's identification to any nearby vessel. Tampering with this identity was deemed theoretically unachievable and was strictly prohibited by law. However, the Millennium Falcon, piloted by Han Solo and Chewbacca, managed to circumvent this security measure. The ship operated under several false identities, such as the Jin-Den Smoke, the Broken Bell, the Foul Matter, and the Lost and Found. The latter alias proved effective shortly after the Battle of Yavin, when the Millennium Falcon was stopped by the Imperial-class Star Destroyer Vehement. Codebreakers could be used to change transponder codes.