Sounds Good? Fast and Secure Contact Exchange in Groups

TL;DR

This paper compares the usability of two contact exchange systems, demonstrating that the new PairSonic protocol improves usability by automating verification, though some users perceive it as less secure due to reduced complexity.

Contribution

The paper introduces PairSonic, a novel contact exchange protocol that enhances usability by automating verification through acoustic channels, extending trust from physical to online encounters.

Findings

PairSonic outperforms SafeSlinger in usability in lab studies.

Users prefer PairSonic despite perceiving it as less secure.

Automating verification reduces user effort but affects security perceptions.

Abstract

Trustworthy digital communication requires the secure exchange of contact information, but current approaches lack usability and scalability for larger groups of users. We evaluate the usability of two secure contact exchange systems: the current state of the art, SafeSlinger, and our newly designed protocol, PairSonic, which extends trust from physical encounters to spontaneous online communication. Our lab study (N=45) demonstrates PairSonic's superior usability, automating the tedious verification tasks from previous approaches via an acoustic out-of-band channel. Although participants significantly preferred our system, minimizing user effort surprisingly decreased the perceived security for some users, who associated security with complexity. We discuss user perceptions of the different protocol components and identify remaining usability barriers for CSCW application scenarios.