Bit Whisperer: Enabling Ad-hoc, Short-range, Walk-Up-and-Share Data Transmissions via Surface-restricted Acoustics

Abstract

Bluetooth requires device pairing to ensure security in data transmission, encumbering a number of ad-hoc, transactional interactions that require both ease-of-use and "good enough"security: e.g., sharing contact information or secure links to people nearby. We introduce Bit Whisperer, an ad-hoc short-range wireless communication system that enables "walk up and share"data transmissions with "good enough"security. Bit Whisperer transmits data to proximate devices co-located on a solid surface through high frequency, inaudible acoustic signals. The physical surface has two benefits: it enhances acoustic signal transmission by reflecting sound waves as they propagate; and, it makes the domain of communication visible, helping users identify exactly with whom they are sharing data without prior pairing. Through a series of technical evaluations, we demonstrate that Bit Whisperer is robust for common use-cases and secure against likely threats. We also implement three example applications to demonstrate the utility of Whisperer: 1-to-1 local contact sharing, 1-to-N private link sharing to open a secure group chat, and 1-to-N local device authentication.