human: Given a node-centered hypergraph: <hypergraph>, where nodes represent papers and hyperedges represent sets of papers co-cited by a source paper.

Details of the hypergraph:
Center node: "why johnny can t store passwords securely a usability evaluation of bouncycastle password hashing"
  Abstract: Lack of usability of security Application Programming In- terfaces (APIs) is one of the main reasons for mistakes that programmers make that result in security vulnerabilities in software applications they develop. Especially, APIs that pro- vide cryptographic functionalities such as password hashing are sometimes too complex for programmers to learn and use. To improve the usability of these APIs to make them easy to learn and use, it is important to identify the usability issues exist on those APIs that make those harder to learn and use. In this work, we evaluated the usability of SCrypt password hashing functionality of Bouncycastle API to identify usabil- ity issues in it that persuade programmers to make mistakes while developing applications that would result in security vulnerabilities. We conducted a study with 10 programmers where each of them spent around 2 hours for the study and attempted to develop a secure password storage solution us- ing Bouncycastle API. From data we collected, we identified 63 usability issues that exist in the SCrypt implementation of Bouncycastle API. Results of our study provided useful insights about how security/cryptographic APIs should be designed, developed and improved to provide a better experi- ence for programmers who use them. Furthermore, we expect that this work will provide a guidance on how to conduct usability evaluations for security APIs to identify usability issues exist in them.

Connected through hyperedge HE-1 (induced by source paper "fighting against xss attacks a usability evaluation of owasp esapi output encoding"):
  with members:
    - "using cognitive dimensions questionnaire to evaluate the usability of security apis"
    - "are easily usable security libraries possible and how should experts work together to create them"

Connected through hyperedge HE-2 (induced by source paper "a methodology to evaluate the usability of security apis"):
  with members:
    - "fighting against xss attacks a usability evaluation of owasp esapi output encoding"
    - "are easily usable security libraries possible and how should experts work together to create them"

Question: Please tell me which class the center node belongs to. The 40 classes are: cs.NA(Numerical Analysis), cs.MM(Multimedia), cs.LO(Logic in Computer Science), cs.CY(Computers and Society), cs.CR(Cryptography and Security), cs.DC(Distributed, Parallel, and Cluster Computing), cs.HC(Human-Computer Interaction), cs.CE(Computational Engineering, Finance, and Science), cs.NI(Networking and Internet Architecture), cs.CC(Computational Complexity), cs.AI(Artificial Intelligence), cs.MA(Multiagent Systems), cs.GL(General Literature), cs.NE(Neural and Evolutionary Computing), cs.SC(Symbolic Computation), cs.AR(Hardware Architecture), cs.CV(Computer Vision and Pattern Recognition), cs.GR(Graphics), cs.ET(Emerging Technologies), cs.SY(Systems and Control), cs.CG(Computational Geometry), cs.OH(Other Computer Science), cs.PL(Programming Languages), cs.SE(Software Engineering), cs.LG(Machine Learning), cs.SD(Sound), cs.SI(Social and Information Networks), cs.RO(Robotics), cs.IT(Information Theory), cs.PF(Performance), cs.CL(Computation and Language), cs.IR(Information Retrieval), cs.MS(Mathematical Software), cs.FL(Formal Languages and Automata Theory), cs.DS(Data Structures and Algorithms), cs.OS(Operating Systems), cs.GT(Computer Science and Game Theory), cs.DB(Databases), cs.DL(Digital Libraries), cs.DM(Discrete Mathematics). Directly output the class name.

gpt: cs.CR(Cryptography and Security)