Developed by Dr. Gaius Baltar, the Command Navigation Program (CNP) was a program utilized by the Colonial military forces of the Twelve Colonies. Presumably installed in the central computers of Vipers and Raptors and in the navigation computers of almost all battlestars, it was a contrivance that was more than two years in the making.
Unbeknownst to Baltar, one of his lovers and co-writers of the CNP turned out to be a version of the Humano-Cylon agent Number Six. She also programmed backdoors into the program so that the Cylon attack force could infiltrate and destroy any CNP-equipped ships without so much as a retaliatory response. Ships with the CNP that received a command from an attacking Cylon ship would see their power, defense networks, and computers shut down as if a switch were flipped.
The CNP was distributed as with all Colonial software updates via the Colonial Defense Mainframe, where Six had unrestricted access on Baltar's authorization.
The CNP was received by battlestar Galactica, but the program was never loaded into primary memory of the ship, although her last squadron of Viper Mark VIIs (led by CAG Jackson Spencer) did receive the upgrade. As a result, the squadron were infiltrated and destroyed by two Cylon Raiders on their way back to Caprica (Mini-Series).
Lieutenant Felix Gaeta has the program code purged from the mainframe on Baltar's suggestion, and the program was also deleted from the flight systems of any of Galactica's surviving Mark VII Vipers and Raptors that had previously received the upgrade.