  Conventional wireless security assumes wireless communications are rightful
and aims to protect them against malicious eavesdropping and jamming attacks.
However, emerging infrastructure-free mobile communication networks are likely
to be illegally used (e.g., by criminals or terrorists) but difficult to be
monitored, thus imposing new challenges on the public security. To tackle this
issue, this article presents a paradigm shift of wireless security to the
surveillance and intervention of infrastructure-free suspicious and malicious
wireless communications, by exploiting legitimate eavesdropping and jamming
jointly. In particular, {\emph{proactive eavesdropping}} (via jamming) is
proposed to intercept and decode information from suspicious communication
links for the purpose of inferring their intentions and deciding further
measures against them. {\emph{Cognitive jamming}} (via eavesdropping) is also
proposed so as to disrupt, disable, and even spoof the targeted malicious
wireless communications to achieve various intervention tasks.
