Automatic dependent surveillance-broadcast is an emerging surveillance technology for the future “e-enabled” aircrafts, which will make it possible for aircrafts to share their location data with neighboring aircrafts, ground controllers, and other interested parties. In order to provide the automatic dependent surveillance-broadcast communications with a high level of accuracy and integrity, a reliable authentication mechanism is required. So far, however, very few cryptographic solutions have been offered to achieve this in the literature. Even existing solutions have faced the following challenges: (i) the authentication solutions based on regular digital signature require complex management of public-key infrastructureell; and (ii) signing messages exchanged or broadcast frequently in aircraft-to-aircraft and aircraft-to-ground communication modes can cause a computational bottleneck easily. In order to address these challenges, we take a fresh approach to building up an authentication framework by introducing a new online/offline identity-based signature scheme. Our scheme will resolve the public-key infrastructure management issue by using the identities of aircrafts as public keys and will achieve a high efficiency through online/offline signature generation. Copyright © 2014 John Wiley & Sons, Ltd.