A Swiss company called Futurae is currently developing an interesting two-step authentication method called Sound Proof. A spin-off from the Swiss Federal Institute of Technology Zurich, the startup wants to use the noise around you to make sure that the person logging into your account is actually you and not a hacker. In truth, some people find the four digit codes that are currently used a bit of a hassle, but from a privacy standpoint, this ambient noise idea is a bit scary.
In case you're curious how it all works, whenever you try to log into a protected account, the security system will listen to about 2-3 seconds of the sound surrounding the device that's being used, then listen to 2-3 seconds of the ambient noise that your mobile is picking up. In case the two match, access will be granted. If there's no noise the Sound Proof method will play ultrasounds, to that it has something to compare with the audio captured from your mobile.
As I previously said, the idea sounds pretty good and it's effortless as all you have to do is to wait a few extra seconds for the authentication process to complete, but the fact that your mobile can suddenly decide to start listening to everything around you is not a very comforting thought. However, the company states that the sounds recorded never leave your smartphone. Furthermore, the need for new security systems is dire as researchers have already broken the current two-factor authentication system, so it's nice to see new ideas on the market.