This isn’t so much a retaliation for China banning their products/services, but rather it was the result of a discovery of unauthorized digital certificates for several of its domains. According to Google, they claim that they certificates were issued by an Egyptian-based company that was an intermediate certificate authority that allowed the CNNIC to operate.
In Google’s blog post, “As a result of a joint investigation of the events surrounding this incident by Google and CNNIC, we have decided that the CNNIC Root and EV CAs will no longer be recognized in Google products. This will take effect in a future Chrome update.” What this means is that Chrome users will get a security warning should they stumble across any new website authenticated by the CNNIC, particular those requiring login information. Some websites might even cease to stop working in Chrome entirely, like banks or commerce websites.
Mozilla issued their own statement in which they more or less echoed what Google said. “Therefore, after public discussion and consideration of the scope and impact of a range of options, we have decided to update our code so that Mozilla products will no longer trust any certificate issued by CNNIC’s roots with a notBefore date on or after 1st April 2015.” The impact of this ban could be huge as it could mean that many users in China would be left unable to connect to their favorite websites, but hopefully the CNNIC will be able work things out with both Google and Mozilla.