Can my iPhone unlock my windows PC

I am looking for an app (either buy or develop) with the following feature - "When I bring my iPhone close to (in bluetooth range) to my windows PC, the PC unlocks by virtue of bluetooth pairing with the iPhone and when it is not in bluetooth range the PC locks". I could not find any such app. Is it because bluetooth 4.0 is not supported by most windows devices or is it because bluetooth iPhone pairing with windows PC is not supported ? There are similar products out there for MAC though (MAC-iphone lock/unlock) like knock or keycard.