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: "the unreasonable fundamental incertitudes behind bitcoin mining"
  Abstract: Bitcoin is a "crypto currency", a decentralized electronic payment scheme based on cryptography which has recently gained excessive popularity. Scientific research on bitcoin is less abundant. A paper at Financial Cryptography 2012 conference explains that it is a system which "uses no fancy cryptography", and is "by no means perfect". It depends on a well-known cryptographic standard SHA-256. In this paper we revisit the cryptographic process which allows one to make money by producing bitcoins. We reformulate this problem as a Constrained Input Small Output (CISO) hashing problem and reduce the problem to a pure block cipher problem. We estimate the speed of this process and we show that the cost of this process is less than it seems and it depends on a certain cryptographic constant which we estimated to be at most 1.86. These optimizations enable bitcoin miners to save tens of millions of dollars per year in electricity bills. Miners who set up mining operations face many economic incertitudes such as high volatility. In this paper we point out that there are fundamental incertitudes which depend very strongly on the bitcoin specification. The energy efficiency of bitcoin miners have already been improved by a factor of about 10,000, and we claim that further improvements are inevitable. Better technology is bound to be invented, would it be quantum miners. More importantly, the specification is likely to change. A major change have been proposed in May 2013 at Bitcoin conference in San Diego by Dan Kaminsky. However, any sort of change could be flatly rejected by the community which have heavily invested in mining with the current technology. Another question is the reward halving scheme in bitcoin. The current bitcoin specification mandates a strong 4-year cyclic property. We find this property totally unreasonable and harmful and explain why and how it needs to be changed.

Connected through hyperedge HE-1 (induced by source paper "a survey on security and privacy issues of bitcoin"):
  with members:
    - "concurrency and privacy with payment channel networks"
    - "dandelion redesigning the bitcoin network for anonymity"
    - "consensus in the age of blockchains"
    - "when the cookie meets the blockchain privacy risks of web payments via cryptocurrencies"
    - "be selfish and avoid dilemmas fork after withholding faw attacks on bitcoin"
    - "socially optimal mining pools"
    - "the balance attack against proof of work blockchains the r3 testbed as an example"
    - "hijacking bitcoin routing attacks on cryptocurrencies"

Connected through hyperedge HE-2 (induced by source paper "bitcoin a money like informational commodity"):
  with members:
    - "the false premises and promises of bitcoin"
    - "questions related to bitcoin and other informational money"
    - "bitcoin and beyond exclusively informational money"
    - "instruction sequence processing operators"
    - "information carriers and identification of information objects an ontological approach"
    - "on the expressiveness of single pass instruction sequences"
    - "informaticology combining computer science data science and fiction science"
    - "ologs a categorical framework for knowledge representation"

Connected through hyperedge HE-3 (induced by source paper "questions related to bitcoin and other informational money"):
  with members:
    - "the false premises and promises of bitcoin"
    - "bitcoin and beyond exclusively informational money"
    - "long multiplication by instruction sequences with backward jump instructions"
    - "decision taking for selling thread startup"
    - "informaticology combining computer science data science and fiction science"
    - "on bitcoin and red balloons"
    - "machine structure oriented control code logic"
    - "a static theory of promises"

Connected through hyperedge HE-4 (induced by source paper "bitcoin and beyond exclusively informational money"):
  with members:
    - "practical aspects of the bitcoin system"
    - "informaticology combining computer science data science and fiction science"
    - "formaleuros formalcoins and virtual monies"
    - "searching publications on operating systems"
    - "on the definition of a theoretical concept of an operating system"
    - "machine structure oriented control code logic"
    - "a static theory of promises"

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)