The court refused to dismiss a case against Google in which individuals claim that the search giant invaded their privacy when it collected data from unencrypted Wi-Fi networks.
The Court rejected Google's argument that US wiretapping law means it was lawful for it to intercept data belonging to members of the public sent over open Wi-Fi networks.
The Wiretap Act, which was updated in 1986 by the Electronic Communications Privacy Act (ECPA), prohibits the interception of radio communications but an exception in the law allows radio communications to be intercepted if they are not scrambled or encrypted and are deemed "readily accessible to the general public", the ruling said.
The judge rejected Google's claims that the exemptions should apply to Wi-Fi communications and has allowed the case against it to be heard at a full trial.
Lawmakers only intended the legal exemptions to apply to communications made via traditional radio services, the judge said in his ruling.
"Merely pleading that a network is unencrypted does not render that network readily accessible to the general public and serve to remove the intentional interception of electronic communications from that network from liability under the Electronic Communications Privacy Act (ECPA)," the judge said in his ruling.
Members of the public claim that Google invaded their privacy by intercepting information about them, the ruling said.
Google obtained the information, which included the name and number of the Wi-Fi network, usernames, passwords and personal email addresses, to improve location-based services, the ruling said.
Google operates map and search services that rely heavily on location data.
The company obtained the information from technology deployed on its Street View vehicles, the ruling said. Google's Street View is a software program that stitches together images of places. It allows users to interactively navigate locations over the internet from a first person perspective.
Earlier this year Google was fined €100,000 by France's privacy regulator after it said the company was collecting WiFi users' data without telling them.
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