Decalogue I doesn't has any themes regarding network security. All the computers in the movies are closed systems, meaning that they don't interact with other computers except for downloading packages. The closest event to hacking is the scene where Krzysztof asks the computer "Colleague, what do you want?' Then, the computer responds with "I am ready." This could imply someone is listening to Krzysztof and they're using the computer as proxy to talk to them. It could be commentary on the infallibility of computing. However, because of the religious nature of the movie, this "person" is most likely not human, and, therefore, is not concern with security.