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: "leveraging decentralization to extend the digital evidence acquisition window case study on bittorrent sync"
  Abstract: File synchronization services such as Dropbox, Google Drive, Microsoft OneDrive, Apple iCloud, etc., are becoming increasingly popular in today's always-connected world. A popular alternative to the aforementioned services is BitTorrent Sync. This is a decentralized/cloudless file synchronization service and is gaining significant popularity among Internet users with privacy concerns over where their data is stored and who has the ability to access it. The focus of this paper is the remote recovery of digital evidence pertaining to files identified as being accessed or stored on a suspect's computer or mobile device. A methodology for the identification, investigation, recovery and verification of such remote digital evidence is outlined. Finally, a proof-of-concept remote evidence recovery from BitTorrent Sync shared folder highlighting a number of potential scenarios for the recovery and verification of such evidence.

Connected through hyperedge HE-1 (induced by source paper "greening cloud enabled big data storage forensics syncany as a case study"):
  with members:
    - "digital forensic investigation of cloud storage services"
    - "network traffic forensics on firefox mobile os facebook twitter and telegram as case studies"
    - "windows instant messaging app forensics facebook and skype as case studies"
    - "a forensically sound adversary model for mobile devices"
    - "cloud storage forensic hubic as a case study"
    - "bittorrent sync first impressions and digital forensic implications"
    - "bittorrent sync network investigation methodology"

Connected through hyperedge HE-2 (induced by source paper "cloudme forensics a case of big data forensic investigation"):
  with members:
    - "greening cloud enabled big data storage forensics syncany as a case study"
    - "forensic investigation of p2p cloud storage bittorrent sync as a case study"
    - "cloud storage forensics analysis of data remnants on spideroak justcloud and pcloud"
    - "digital forensic investigation of cloud storage services"
    - "windows instant messaging app forensics facebook and skype as case studies"
    - "a forensically sound adversary model for mobile devices"
    - "cloud storage forensic hubic as a case study"
    - "bittorrent sync first impressions and digital forensic implications"

Connected through hyperedge HE-3 (induced by source paper "forensic investigation of p2p cloud storage bittorrent sync as a case study"):
  with members:
    - "ubuntu one investigation detecting evidences on client machines"
    - "digital forensic investigation of cloud storage services"
    - "windows instant messaging app forensics facebook and skype as case studies"
    - "mobile cloud forensics an analysis of seven popular android apps"
    - "network investigation methodology for bittorrent sync"
    - "bittorrent sync first impressions and digital forensic implications"
    - "bittorrent sync network investigation methodology"
    - "seclaas secure logging as a service for cloud forensics"

Connected through hyperedge HE-4 (induced by source paper "battling the digital forensic backlog through data deduplication"):
  with members:
    - "increasing digital investigator availability through efficient workflow management and automation"
    - "current challenges and future research areas for digital forensic investigation"
    - "tiered forensic methodology model for digital field triage by non digital evidence specialists"
    - "automated inference of past action instances in digital investigations"

Connected through hyperedge HE-5 (induced by source paper "network investigation methodology for bittorrent sync"):
  with members:
    - "digital forensic investigation of cloud storage services"
    - "bittorrent sync first impressions and digital forensic implications"
    - "spying the world from your laptop identifying and profiling content providers and big downloaders in bittorrent"

Connected through hyperedge HE-6 (induced by source paper "project maelstrom forensic analysis of the bittorrent powered browser"):
  with members:
    - "network investigation methodology for bittorrent sync"

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)