If your mobile phone has a speaker and a microphone, you may soon be able to use them to transfer files to other mobile phones without the need for any special hardware. That's the promise of a recently published paper by Microsoft Research that describes what it calls Secure Peer-to-Peer Acoustic NFC.
Usually NFC (Near Field Communication) requires that a special chip be put inside a mobile phone or tablet in order to work. However, there are still a ton of mobile phones out there without NFC hardware. The Microsoft Research paper from the company's India team has come up with a software only solution for all those phones, which has the name Dhwani.
In very basic terms, once the Dhwani software is installed on mobile phones, one of them can use sound to transmit data via the speaker to another phone's microphone. According to the team that created Dhwani, they have been able to use the software to transfer data at a rate of 2.4 kilobits per second. Yes, that's very slow but the researchers say it would be enough to enable a phone with the software to send a payment to a store counter or another phone, among other applications.
What about if another phone is nearby? Microsoft Research has that covered as well with what it calls JamSecure. The paper's authors summarizes the technique stating, " ... the receiver intentionally jams the signal it is trying to receive, thereby stymieing eaves-droppers, but then uses self-interference cancellation to successfully decode the incoming message."