Team for Research in
Ubiquitous Secure Technology

Citation
Chris Karlof, Doug Tygar, David Wagner. "Conditioned-safe Ceremonies and a User Study of an Application to Web Authentication". Sixteenth Annual Network and Distributed Systems Security Symposium, 2009.

Abstract
We introduce the notion of a conditioned-safe ceremony. A “ceremony” is similar to the conventional notion of a protocol, except that a ceremony explicitly includes human participants. Our formulation of a conditioned-safe ceremony draws on several ideas and lessons learned from the human factors and human reliability community: forcing functions, defense in depth, and the use of human tendencies, such as rule-based decision making. We propose design principles for building conditioned-safe ceremonies and apply these principles to develop a registration ceremony for machine authentication based on email. We evaluated our email registration ceremony with a user study of 200 participants. We designed our study to be as ecologically valid as possible: we employed deception, did not use a laboratory environment, and attempted to create an experience of risk. We simulated attacks against the users and found that email registration was significantly more secure than challenge question based registration. We also found evidence that conditioning helped email registration users resist attacks, but contributed towards making challenge question users more vulnerable.

Electronic downloads

• http://www.cs.berkeley.edu/~ckarlof/papers/conditioned-safe-ndss09.pdf

• HTML

  Chris Karlof, Doug Tygar, David Wagner. <a
  href="http://www.truststc.org/pubs/498.html"
  >Conditioned-safe Ceremonies and a User Study of an
  Application to Web Authentication</a>,  Sixteenth
  Annual Network and Distributed Systems Security Symposium,
  2009.

• Plain text

  Chris Karlof, Doug Tygar, David Wagner.
  "Conditioned-safe Ceremonies and a User Study of an
  Application to Web Authentication".  Sixteenth Annual
  Network and Distributed Systems Security Symposium, 2009.

• BibTeX

  @inproceedings{KarlofTygarWagner09_ConditionedsafeCeremoniesUserStudyOfApplicationToWeb,
      author = {Chris Karlof and Doug Tygar and David Wagner},
      title = {Conditioned-safe Ceremonies and a User Study of an
                Application to Web Authentication},
      booktitle = { Sixteenth Annual Network and Distributed Systems
                Security Symposium},
      year = {2009},
      abstract = {We introduce the notion of a conditioned-safe
                ceremony. A �ceremony� is similar to the
                conventional notion of a protocol, except that a
                ceremony explicitly includes human participants.
                Our formulation of a conditioned-safe ceremony
                draws on several ideas and lessons learned from
                the human factors and human reliability community:
                forcing functions, defense in depth, and the use
                of human tendencies, such as rule-based decision
                making. We propose design principles for building
                conditioned-safe ceremonies and apply these
                principles to develop a registration ceremony for
                machine authentication based on email. We
                evaluated our email registration ceremony with a
                user study of 200 participants. We designed our
                study to be as ecologically valid as possible: we
                employed deception, did not use a laboratory
                environment, and attempted to create an experience
                of risk. We simulated attacks against the users
                and found that email registration was
                significantly more secure than challenge question
                based registration. We also found evidence that
                conditioning helped email registration users
                resist attacks, but contributed towards making
                challenge question users more vulnerable.},
      URL = {http://www.truststc.org/pubs/498.html}
  }
  

Posted by Chris Karlof on 28 Jan 2009.
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