General Info

  • Dr. Andrew Besmer

Dr. Andrew Besmer

Assistant Professor

Department of Computer Science and Quantitative Methods

College of Business Administration

Office: 304 Thurmond

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Phone: 803-323-4825

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Office Hours

Office hours are all held in Thurmond 304. You can also make an appointment outside of my office hours if you need.

See your syllabus for office hour times or the hours posted on my door.

My research is in the area of Privacy and Security particularly with regard to Human Computer Interaction. I utilize a variety of methods in my work including prototype development, quantitative, and qualitative analysis. I am working on creating effective ways to configure security and privacy policies, currently focused on the configuration of policies for third party applications. As part of this research, I am exploring contextual configuration of policies at runtime instead of install time. Instead of forcing users to learn the way security systems are designed, we should be designing our security systems to work for our users. On occasion, this may mean modifying the underlying access control frameworks to meet these needs. This is the way I have approached the usable security problem in my research. I try to understand the user and their needs in order to inform the design of the underlying access control systems.

Access Control

Application platforms on both Social Network Sites (SNS) and mobile platforms have become increasingly popular. Unfortunately the applications on these platforms have had access to massive quantities of user data and many users did not understand the implications of their sharing [2]. As a first step, I proposed a new mechanism and interface to correct the mental model and provide a more secure framework for SNS application platforms. Instead of working from access control system and trying to produce a design to fit on top of it, the design was used to produce the access control model. The design itself consisted of granular permissions paired with real user data to illustrate the types of information being shared. Additionally, the fact that friends data was also being consumed was reflected in the design. Finally, a link to additional information about the reason for the data sharing and an indication of other users willingness to share was presented.

The resulting access control model included "friendship based protection" which offered additional benefits to users who were unknowingly having their data consumed. I performed a user study of the prototype and found that a group of users was motivated to configure policies that were appropriate given the nature of the application requesting the data yet others were not [3]. I believe the partial success was because permissions were being configured at install time where participants had little to reason with other than the name of the application.

This has prompted my inquiry into contextual access control. Contextual access control promotes configuring the policies at run time and as close to the interaction where the permission is needed. By addressing policy configuration at runtime the user is able to reason with more information than they could at install time. As a result, users may benefit from more appropriate policies. I have performed an initial study on Android and I am preparing a study on Facebook [6]. This will lead to our better understanding of the tradeoffs between configuration of access control policies at install time and runtime.

Social Navigation

When configuring access control policies for social applications users must make a decision to allow or deny access to profile data attributes. For users this may not be so straightforward and they might not know which decision is best. Social navigation allows the user to see previous decisions made by themselves or others in order to help with the decision at hand. I performed an empirical study of 408 Amazon Mechanical Turkers to see if social navigation could have an observable effect on user decision making in a privacy context. I found that social navigation can result in statistically significant differences in the behavior of participants, but only for those given a strongly negative indication [5]. The results are encouraging because when users are provided a sufficiently negative warning, they will adjust their behavior to be consistent with perceived social norms.

Privacy Policies for Tagged Photographs

Social network sites brought about the phenomena of tagged photos; photos uploaded by others being shared on another person's profile. I performed a series of focus groups to understand concerns, design considerations, and conflict resolution [1]. Since no mechanism existed I created "Restrict Others" around the design considerations extracted from the focus groups. It allows a tagged user to request that any number of their friends be prevented from seeing the photograph, relying on the social relationship to influence the uploader to respect the moral obligation to protect the tagged user. A study of Restrict Others suggests that in most cases uploaders will apply the policies on behalf of the tagged users [4]. This work received a best paper nomination at the premier international conference on Human Computer Interaction (CHI), the top venue for HCI research.

Future Research

I would like to continue to do research in the area of usable privacy and security. There is a seemly endless supply of interfaces with dropdowns, checkboxes, and confusing models that represent the underlying access control systems or privacy configuration mechanisms for any number of domains. Finding solutions to these hard problems has the potential to protect millions of users from unnecessary harm. I look forward to finding areas where my background is a natural fit for collaboration with other students, researchers, and faculty.


  • [1] A. Besmer and H. Lipford. Tagged Photos: Concerns, Perceptions, and Protections. In CHI EA ’09: CHI ’09 Extended Abstracts on Human Factors in Computing Systems, pages 4585–4590, New York, NY, USA, 2009. ACM.
  • [2] A. Besmer and H. R. Lipford. Users’ (Mis)conceptions of Social Applications. In GI ’10: Proceedings of Graphics Interface 2010, pages 63–70, Toronto, Ont., Canada, Canada, 2010. Canadian Information Processing Society.
  • [3] A. Besmer, H. R. Lipford, M. Shehab, and G. Cheek. Social Applications: Exploring a More Secure Framework. In SOUPS ’09: Proceedings of the 5th Symposium on Usable Privacy and Security, pages 1–10, New York, NY, USA, 2009. ACM.
  • [4] A. Besmer and H. Richter Lipford. Moving Beyond Untagging: Photo Privacy in a Tagged World. In CHI ’10: Proceedings of the SIGCHI Conference on Human Factors in Computing Systems, pages 1563–1572, New York, NY, USA, 2010. ACM.
  • [5] A. Besmer, J. Watson, and H. R. Lipford. The Impact of Social Navigation on Privacy Policy Configuration. In SOUPS ’10: Proceedings of the Sixth Symposium on Usable Privacy and Security, pages 1–10, New York, NY, USA, 2010. ACM.
  • [6] A. Besmer, J. Watson, and H. R. Lipford. Poster: Exploring Contextually Bounded Access Control. In Symposium on Usable Privacy and Security, 2011.


  • Configuration of Application Permission with Contextual Access Control - 2013

Refereed Conferences and Workshops with Proceedings

  • J. Watson, A. Besmer, and H. R. Lipford, +Your Circles: Sharing Behavior on Google+. Proceedings of the Eighth Symposium on Usable Privacy and Security (SOUPS 2012), July 2012.
  • A. Besmer, J. Watson, and H. R. Lipford, The Impact of Social Navigation on Privacy Policy Configuration. Proceedings of the Sixth Symposium on Usable Privacy and Security (SOUPS 2010), July 2010.
  • A. Besmer, H. R. Lipford, Users’ (Mis) Conceptions of Social Applications. Proceedings of Graphics Interface, (GI 2010), June 2010, pp 63-70
  • A. Besmer, H. R. Lipford, Moving Beyond UnTagging: Photo Privacy in a Tagged World. Proceedings of the ACM Conference on Human Factors in Computing Systems, CHI 2010, April 2010, pp 1563-1572. Best Paper Honorable Mention
  • H. R. Lipford, G. Hull, C. Latulipe, A. Besmer, J. Watson, Visible Flows: Contextual Integrity and the Design of Privacy Mechanisms on Social Network Sites. Proceedings of the Workshop on Security and Privacy in Online Social Networking, IEEE International Conference on Social Computing (SocialCom), August 2009.
  • A. Besmer, H.R. Lipford, M. Shehab, G. Cheek, Social Applications: Towards a Secure Framework. In Symposium on Usable Privacy & Security 2009 (SOUPS 2009), Google Headquarters, Mountain View CA, July 2009.
  • H. R. Lipford, A. Besmer, and J. Watson. Understanding Privacy Settings in Facebook with an Audience View. In Usability, Psychology, and Security 2008 (UPSEC 2008), Berkeley, CA, April 2008. USENIX Association.


  • A. Besmer, J. Watson, H. Lipford, Exploring Contextually Bounded Access Control, Symposium on Usable Privacy and Security 2011, Refereed
  • A. Besmer, H. Lipford, Privacy Perceptions in Photo Sharing, Symposium on Usable Privacy and Security 2008, Refereed
  • A. Besmer, H. Lipford, Tagged Photos: Concerns, Perceptions, and Protections, Computer Human Interaction 2009, Refereed

University Service

  • Library Liaison Officer for Computer Science - 2013
  • Secretary for Department of Computer Science and Quantitative Methods - 2013
  • Explore UNC Charlotte - 2008-2012
  • GPSG Treasurer - 2010-2011
  • Student Activity Fees Commission Board Member - 2010-2011
  • Faculty Academic Policy and Standards Committee - 2008-2011
  • GPSG Finance Committee - 2008-2011
  • CCI Grads Treasurer - 2007-2011
  • Department 5 Year Strategic Planning Committee - 2010
  • Subcommittee on Academic Probation and Suspension - 2010
  • Dean Search Committee - 2008-2009
  • Student Government Association Senator - 2003-2005
  • Chairman Student Affairs Committee - 2004

Academic Service

  • UIST - 2013
  • ACM SIG CHI Conference on Computer Human Iteration - 2010-2012
  • Journal of Computers and Security - 2011


  • Graduate Assistance in Areas of National Need Fellowship - 2007-2013
  • Graduate Professional Student Government Distinguished Service Award - 2012
  • Student Activity Fees Commission Certificate - 2011
  • Dr. Brenda Richardson Award - 2004
  • Student Government Senate Certificate - 2004