Google is encrypting traffic that traverses data centre interconnection links after learning that the US National Security Agency (NSA) had been tapping the cables to siphon internal data.
Security engineer Mike Hearn took to Google+ in a personal capacity to reveal the change and to vent about the latest insight into the NSA's overreach, which is contained in a slide deck leaked by former contractor Edward Snowden.
The slides, published by the Washington Post, show the NSA had been "copying entire data flows across leased fibre optic cables that carry information among the data centres" of Google and Yahoo!.
Samples of log files in the slides reveal details of Google's internal traffic flows, and outraged Hearn and others within Google to act.
"The traffic shown in the slides below is now all encrypted and the work the NSA/GCHQ [UK Government Communications Headquarters] staff did on understanding it, ruined," Hearn said.
According to Hearn, one of the slides "shows a database recording a user login" as part of an anti-hacking system he worked on for over two years.
"We designed this system to keep criminals out," he said. "There's no ambiguity here."
Hearn said his post amounted to 'a giant F*** You' to the NSA and its UK counterpart for intercepting the web service provider's data.
Google engineer Brandon Downey has also previously railed against the NSA over the interception revelations, saying he had spent the past decade trying to keep customers safe from a great many network-borne threats.
The engineers were joined in their condemnation of the NSA by Google executive chairman Eric Schmidt who called the data interception "outrageous" in an interview with the Wall Street Journal.
Schmidt said Google had complained about the interception to the NSA, US president Barack Obama and individual members of the US Congress lower house.