Security clearance

Security clearance or security verification is a level of authority given to an officer based on rank, status and position. Computers then identify the individuals by the entry of their vocal or numerical authorization code. Alternatively, specially programmed isolinear rods entered into the computer can also allow various levels of security clearance. (DS9: "Babel", "The Passenger", "Vortex")

Clearance Level Accessibility

Du-ko-cha

High level clearance used by members of the Klingon High Council. Ambassador K'Ehleyr was denied access to files on the Klingon Imperial information net relating to the High Council's inquiries into the Khitomer Massacre because Duras had restricted the files to du-ko-cha clearance or higher. (TNG: "Reunion")

Level 1

Allows access to stations personnel and official logs. (DS9: "Whispers")
Allows access to weapons locker for Starfleet personnel. (DS9: "Tribunal")

Level 4

Required access level to be a Starfleet Intelligence officer. (DS9: "Soldiers of the Empire")
Allows access to Deep Space 9's ship-departure logs. (DS9: "Vortex")

Level 4 Alpha

Required access level for access to an alien starship's black box on the Enterprise NX-01. (ENT: "Affliction")

Level 5 (and above)

Required access to show the layout of DS9, while highlighting all repaired replicators on the command level. (DS9: "Babel")

Level 6 (and above)

For senior officers only. Needed to access Deck 12, section 42 of the USS Voyager around 2376. It was here where an electromagnetic life-form was living in an artificial environment until a new Class J nebula could be found for it to reside. (VOY: "The Haunting of Deck Twelve")

Level 7 (and above)

Allows access to weapons locker for non-station operations personnel. (DS9: "Captive Pursuit")
Allows access to runabout launch pads. (DS9: "The Passenger")

Level 9

Required to override Cardassian security program initiated during a Bajoran revolt. (DS9: "Civil Defense")

Level 10

This security level is for information labeled as for Captain's eyes only. (VOY: "The Haunting of Deck Twelve")
Required to access the Omega One data file, which contains information on the Omega Directive. (VOY: "The Omega Directive")