|Title||An Authentication Protocol using Ultrasonic Ranging|
|Year of Publication||2006|
|Authors||Mayrhofer, R., Gellersen H., & Hazas M.|
This report presents a method for establishing and securing spontaneous interactions on the basis of spatial references which are obtained by accurate sensing of relative device positions. Utilising the Relate ultrasonic sensing system, we construct an interlocked protocol using radio frequency messages and ultrasonic pulses for verifying that two devices share a secret. This verification is necessary to prevent man-in-the-middle attacks on standard Diffie-Hellman key agreement.