Keystroke-Based User Identification on Smart Phones

  • Saira Zahid
  • Muhammad Shahzad
  • Syed Ali Khayam
  • Muddassar Farooq
Part of the Lecture Notes in Computer Science book series (LNCS, volume 5758)


Smart phones are now being used to store users’ identities and sensitive information/data. Therefore, it is important to authenticate legitimate users of a smart phone and to block imposters. In this paper, we demonstrate that keystroke dynamics of a smart phone user can be translated into a viable features’ set for accurate user identification. To this end, we collect and analyze keystroke data of 25 diverse smart phone users. Based on this analysis, we select six distinguishing keystroke features that can be used for user identification. We show that these keystroke features for different users are diffused and therefore a fuzzy classifier is well-suited to cluster and classify them. We then optimize the front-end fuzzy classifier using Particle Swarm Optimization (PSO) and Genetic Algorithm (GA) as back-end dynamic optimizers to adapt to variations in usage patterns. Finally, we provide a novel keystroke dynamics based PIN (Personal Identification Number) verification mode to ensure information security on smart phones. The results of our experiments show that the proposed user identification system has an average error rate of 2% after the detection mode and the error rate of rejecting legitimate users drops to zero in the PIN verification mode. We also compare error rates (in terms of detecting both legitimate users and imposters) of our proposed classifier with 5 existing state-of-the-art techniques for user identification on desktop computers. Our results show that the proposed technique consistently and considerably outperforms existing schemes.


Particle Swarm Optimization Mobile Phone Smart Phone Radial Basis Function Network Back Propagation Neural Network 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2009

Authors and Affiliations

  • Saira Zahid
    • 1
  • Muhammad Shahzad
    • 1
  • Syed Ali Khayam
    • 1
    • 2
  • Muddassar Farooq
    • 1
  1. 1.Next Generation Intelligent Networks Research Center (nexGIN RC)National University of Computer & Emerging Sciences (FAST-NUCES)IslamabadPakistan
  2. 2.School of Electrical Engineering & Computer Science (SEECS)National University of Sciences & Technology (NUST)IslamabadPakistan

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