I was going to say China would use submarines for such, but they don't appear to have many (in contrast to USA) [1]. My next consideration would be China's red team (APT) but I'm unsure about aircraft carriers being hackable. I mean, it'd make a great fiction novel, perhaps a sequel to Cryptonomicon. Where does China's military strength lie?

[1] https://en.wikipedia.org/wiki/List_of_submarine_classes_in_s...