I agree. The most obvious explanation (which may not be correct, of course) for these engineering changes is that Google is trying to armor its network against

I agree. The most obvious explanation (which may not be correct, of course) for these engineering changes is that Google is trying to armor its network against state-sponsored surveillance. BTW it's every two weeks: http://news.cnet.com/8301-13578_3-57591560-38/facebooks-outmoded-web-crypto-opens-door-to-nsa-spying/ http://news.cnet.com/8301-13578_3-57591560-38/facebooks-outm... Langley added: "We would have totally eaten the cost and the speed years ago -- if we could have done it without worries." As an additional precaution, Langley said, Google usually rotates its RSA keys every two weeks.