Passphone: Outsourcing Phone-based Web Authentication while Protecting User Privacy

Martin Potthast; Christian Forler; Eik List; Stefan Lucks

Paper 2017/158

Passphone: Outsourcing Phone-based Web Authentication while Protecting User Privacy

Martin Potthast, Christian Forler, Eik List, and Stefan Lucks

Abstract

This work introduces PassPhone, a new smartphone-based authentication scheme that outsources user verification to a trusted third party without sacrificing privacy: neither can the trusted third party learn the relation between users and service providers, nor can service providers learn those of their users to others. When employed as a second factor in conjunction with, for instance, passwords as a first factor, our scheme maximizes the deployability of two-factor authentication for service providers while maintaining user privacy. We conduct a twofold formal analysis of our scheme, the first regarding its general security, and the second regarding anonymity and unlinkability of its users. Moreover, we provide an automatic analysis using AVISPA, a comparative evaluation to existing schemes under Bonneau et al.'s framework, and an evaluation of a prototypical implementation.

Metadata

Available format(s): PDF
Category: Cryptographic protocols
Publication info: Published elsewhere. Major revision. NordSec2016
DOI: 10.1007/978-3-319-47560-8
Keywords: two-factor authentication unlinkability
Contact author(s): eik list @ uni-weimar de
History: 2017-02-22: received
Short URL: https://ia.cr/2017/158
License: CC BY

BibTeX

@misc{cryptoeprint:2017/158,
      author = {Martin Potthast and Christian Forler and Eik List and Stefan Lucks},
      title = {Passphone: Outsourcing Phone-based Web Authentication while Protecting User Privacy},
      howpublished = {Cryptology {ePrint} Archive, Paper 2017/158},
      year = {2017},
      doi = {10.1007/978-3-319-47560-8},
      url = {https://eprint.iacr.org/2017/158}
}