Urs Hengartner's research is supported by Google. We thank Research in Motion for providing us with two BlackBerry 8820 devices. We also thank Xiaoxiao Li for extracting and modifying the relevant BouncyCastle source files, Earl Oliver for his SMS-based data channel, and Ben Ko for creating the configuration dialog for the NearbyFriend Pidgin plugin. Finally, we acknowledge the developers of the Off-the-Record (OTR) messaging plugin, whose code served as a starting point for the NearbyFriend Pidgin plugin.