Connect to a trusted device only

[rookie]

I am looking for a way only a known/trusted device can connect and write/read information from my device. Filtering by address(white-listing) is not feasible. So what is a way this can be achieved? Security tokens, crypto challenge or any other means? I'm looking for a way that this gets handled during the connection handshaking if possible.

[Susheel Nuguru]

Everything before a connection and pairing is open sniffable data. So, in my opinion, you should have atleast one level of encryption before you validate that the peer . After pairing you can ask the peer to transfer few security tokens to which which could be decoded in your device. 
In short, validing a peer in an open unencrypted link could leave attackers a possiblity to analyze the algorithm by which you are trying to validate peers.