Check out the new USENIX Web site.

Home About USENIX Events Membership Publications Students
MobiSys '03 Abstract

Protecting Applications with Transient Authentication

Mark D. Corner and Brian D. Noble, University of Michigan


How does a machine know who is using it? Current systems authenticate their users infrequently, and assume the user's identity does not change. Such persistent authentication is inappropriate for mobile and ubiquitous systems, where associations between people and devices are fluid and unpredictable. We solve this problem with Transient Authentication, in which a small hardware token continuously authenticates the user's presence over a short-range, wireless link. We present the four principles underlying Transient Authentication, and describe two techniques for securing applications. Applications can be protected transparently by encrypting in-memory state when the user departs and decrypting this state when the user returns. This technique is effective, requiring just under 10 seconds to protect and restore an entire machine, but indiscriminate. Instead, applications can utilize an API for Transient Authentication, protecting only sensitive state. We describe our ports of three applications — PGP, SSH, and Mozilla — to this API. Mozilla, the most complicated application we have ported, suffers less than 4% overhead in page loads in the worst case, and in typical use can be protected in less than 250 milliseconds.
  • View the full text of this paper in PDF.
    Click here if you have forgotten your password Until May 2004, you will need your USENIX membership identification in order to access the full papers. The Proceedings are published as a collective work, © 2003 by the USENIX Association. All Rights Reserved. Rights to individual papers remain with the author or the author's employer. Permission is granted for the noncommercial reproduction of the complete work for educational or research purposes. USENIX acknowledges all trademarks within this paper.

  • If you need the latest Adobe Acrobat Reader, you can download it from Adobe's site.
To become a USENIX Member, please see our Membership Information.

?Need help? Use our Contacts page.

Last changed: 7 Nov. 2003 jel
Technical Program
MobiSys '03 Home