sharing something which is so secret via bluetooth or wi-fi , then beware of eavesdropper(hacker) ..he will encrypt your secret code..!!!! then how will you ????

don’t worry friend ther’s NFC tech. which will help you..!!!

Wi-Fi and Bluetooth receivers already make it easy to send information from one phone to another, and handsets equipped with near field communication (NFC) technology will soon let you pay for a coffee with a swipe of your phone, but how can you be sure that no one else is listening in?

There’s always the risk with any wireless communication that an eavesdropper will intercept your message, so encryption is a must, but that means securely exchanging an encryption key beforehand. The current solution often requires users to manually enter a key – think pairing two Bluetooth devices with a four-digit code – or simultaneously press a button on both devices, but this exchange could also be snooped on by a determined attacker.

Eric Medvet and colleagues have encoded the encryption key as flashes of colour on the screen of one phone that are picked up by the camera of another, in a system they call Rainbow Crypt.

They place the phones in direct contact to ensure that no one else can see the flashing colours. Phone cameras are not normally designed to focus at such a short range, but it is possible for them to pick up a single block of colour. Medvet says a five-second sequence is enough to transmit a 42-bit encryption key.

The video above gives you an idea of how this would work, though in a real-life situation the receiving phone’s screen would of course be blanked out. The team will present their work at the Intelligent Systems Design and Applications conference in Córdoba, Spain at the end of the month.
                                                                    posted by

                                               hariharasravan(mgit ece 2nd yr)