The EyeTap's functionality and minimalist appearance have been compared to Steve Mann's EyeTap,[76] also known as "Glass" or "Digital Eye Glass", although Google Glass is a "Generation-1 Glass" compared to EyeTap, which is a "Generation-4 Glass".[77] According to Mann, both devices affect both privacy and secrecy by introducing a two-sided surveillance and sousveillance.[78] Concerns have been raised by various sources regarding the intrusion of privacy, and the etiquette and ethics of using the device in public and recording people without their permission.[79][80][81] There is controversy that Google Glass would violate privacy rights due to security problems and others.[82][83][84]