Content is distributed from a source to a sink only if the sink is within a predetermined geographic locality. In one embodiment, a signature request is sent to the sink. The sink obtains an actual signature compares it to the requested signature, and if the requested signature and the actual signature resemble each other sufficiently closely, then the content is sent to the sink The signature is compiled from parameters obtained from appropriate parameter detectors. The parameter detectors generate, detect and monitor various signals required for determining the locality of the sink.