Signal, e.g., message, security techniques are described for wireless systems. A first signal is received by an access node via a wireless link. The signal includes a first authenticator that was generated by the transmitting device, e.g., wireless terminal. The access node determines from an attribute of the signal at least some information known to both the access node and transmitting device but which was not transmitted as part of the message content. The determined information was used by the wireless terminal in generating the first authenticator. The access node sends at least a portion of the first signal including the first authenticator and the determined information to another entity. The entity compares the first authenticator to a second authenticator it generates from the determined information and a secure key which it shares with the transmitting device to determine if the first and second authenticators match.