Hotword listens for specific key words chosen to activate the “OK Google” voice interface. The program is then readied for voice-based search, questions and commands. Voice interfaces use speech recognition technologies to allow user input through spoken commands. The software identifies spoken words and phrases and converts them to a machine-readable format for interaction.
The hotword module itself is black-boxed – meaning that its inner workings are not transparent -- and not open source. Privacy advocates became concerned when developers detected the module and reported that it installs without user permission and can start listening automatically. Author and journalist Cory Doctorow reported that hotword’s default behavior is to “silently switch on your computer's microphone and send whatever it hears to Google.”
Google maintains that the software is opt-in and designed only to allow verbal interaction with the computer. The company further states that it does not control Chromium development and that some of the issue results from the fact that Debian downloads Chromium automatically rather than Chrome.
Nevertheless, developers have recorded instances of the software automatically downloading and initiating without user input. According to Rich Falkvinge:“The default install will still wiretap your room without your consent, unless you opt out, and more importantly, know that you need to opt out, which is nowhere a reasonable requirement.” Falkvinge is the founder of the Pirate Party, an international political party whose platform includes freedom of information, citizen participation, privacy rights and transparency (among other things).
Communications privacy has become an increasingly sensitive issue since the Snowden disclosures of 2013 revealed that the NSA (National Security Agency) had full access to user data on the servers of major service providers, including Google.
Falkvinge advises that the only real way to protect user privacy from eavesdropping software is to build a hardware switch into devices that can disable any listening module that may be installed.