human: Given a hyperedge-centered hypergraph: <hypergraph>, where the center hyperedge is induced by one source paper and its member nodes are the cited papers.

Details of the hypergraph:
Center hyperedge (induced by source paper "topological study and lyapunov exponent of a secure steganographic scheme"):
  Abstract: CIS2 is a steganographic scheme proposed in the information hiding literature, belonging into the small category of algorithms being both stego and topologically secure. Due to its stego-security, this scheme is able to face attacks that take place into the "watermark only attack" framework. Its topological security reinforce its capability to face attacks in other frameworks as "known message attack" or "known original attack", in the Simmons' prisoner problem. In this research work, the study of topological properties of C I S 2 is enlarged by describing this scheme as iterations over the real line, and investigating other security properties of topological nature as the Lyapunov exponent. Results show that this scheme is able to withdraw a malicious attacker in the "estimated original attack" context too.

Includes members:
  Member "hash functions using chaotic iterations":
    also connected through other hyperedges:
      - Hyperedge HE-1 (induced by source paper "low cost monitoring and intruders detection using wireless video sensor networks")
  Member "lyapunov exponent evaluation of a digital watermarking scheme proven to be secure":
    also connected through other hyperedges:
      - Hyperedge HE-2 (induced by source paper "a cryptographic approach for steganography")
  Member "chaotic iterations versus spread spectrum chaos and stego security":
    also connected through other hyperedges:
      - Hyperedge HE-3 (induced by source paper "a cryptographic approach for steganography")

Question: Please tell me which class the source paper 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)