Description of the attempted terrorist attack:
Two individuals are about to introduce explosive devices in the stadium; they are getting close to the perimeter controls of access to the stadium. Concurrently, a stolen vehicle of more than 3500 kg is going to be used by another individual in order to run over people in one of the accesses to the stadium, moments before the beginning of the football game. Moreover, in order to remain undiscovered, the terrorists are utilising information hiding tools on their smartphones in the form of network steganography (i.e. which are able to slightly modify the legitimate, outgoing data streams in order to embed secret information there, so it is invisible to the unaware third parties) to covertly communicate and plan/synchronise their activities.