The head of GCHQ has warned that the technology threat posed by Russia is like finding a vulnerability on your phone - a risk but one that can probably be mitigated - whereas China has the potential to control the "global operating system".
Jeremy Fleming said the UK and its allies face a "moment of reckoning" to stop authoritarian regimes like China from dominating key technologies of the future in a Darwinian-style evolution that would ensure their values rather than democratic ones are dominant.
In a lecture, the spy chief offered a new analogy to describe the respective challenge Moscow and Beijing pose in the technology space.
"The threat posed by Russia's activity is like finding a vulnerability on a specific app on your phone - it's potentially serious, but you can probably use an alternative," he said.
"However, the concern is that China's size and technological weight means that it has the potential to control the global operating system."
China - which Mr Fleming said has a competing vision for the future of cyberspace to the West - has been quick to implement emerging technologies that are changing the way the world works. It also has a strong voice in debates around international rules and standards that will govern these technologies.
"States that do not share our values build their own illiberal values into the standards and technology upon which we may become reliant," Mr Fleming said.
"If that happens, and it turns out to be insecure or broken or undemocratic, everyone is going to be facing a very difficult future."
The GCHQ chief said there has been "concerted campaigns" to dominate organisations that develop standards for certain technologies.
There have also been "determined efforts" to use issues of common concern - like climate change - to gain footholds in new technology markets.
"Smart cities are a case in point. They provide great promise to make urban areas more efficient and less polluting through the use of data," he said in the Imperial College Vincent Briscoe Annual Security Lecture.
"The vision is for smart cities to know everything about things, but nothing about individuals. They should help you navigate life, not track your movements.
"But unchecked, or implemented in the wrong way, there's a risk that we will import technology which hardwires data collection in ways that go against the interests and values of open, democratic societies."
Mr Fleming said cybersecurity is an issue that affects the whole nation.
The rules are changing in ways not always controlled by the government. And without action it is increasingly clear that the key technologies on which we will rely for our future prosperity and security won't be shaped and controlled by the West," he said.
"So, we are now facing a moment of reckoning. In the natural world, during a period of rapid change, the only option is to adapt. And it's the same for us."