Anti-Spoof [National Security] Law and Legal Definition

Anti-spoof means a process of encrypting P-Code information so that non-U.S. military user’s participation in a telecommunications network or operation control of a cryptographic or communications security system is prevented. Anti-spoofing was enforced on January 31, 1994, by the secret encryption called the "W-code" onto the P-code. Since the military PRN code is kept secret, an enemy of the U.S. cannot jam the satellite signal through ground-based transmitters, nor can they spoof military global positioning system receivers (GPS receivers) by transmitting a false P-code signal from a satellite.