Starfleet ID code
A Starfleet ID code was an identification used by Starfleet officers. The code was classified to civilians and known only to members of Starfleet.

In an alternate 2374, a captured Tom Paris sent a message along with a Starfleet ID code to the severely damaged  from Annorax's weapon ship. Captain Kathryn Janeway was convinced the code could only have come from Paris. The message with the code contained the coordinates of the weapon ship, which Janeway later destroyed, with help from the Nihydron and the Mawasi. ()
Identification technology