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: "two attacks on rank metric code based schemes ranksign and an identity based encryption scheme"
  Abstract: RankSign [GRSZ14a] is a code-based signature scheme proposed to the NIST competition for quantum-safe cryptography [AGHRZ17] and, moreover, is a fundamental building block of a new Identity-Based-Encryption (IBE) [GHPT17a]. This signature scheme is based on the rank metric and enjoys remarkably small key sizes, about 10KBytes for an intended level of security of 128 bits. Unfortunately we will show that all the parameters proposed for this scheme in [AGHRZ17] can be broken by an algebraic attack that exploits the fact that the augmented LRPC codes used in this scheme have very low weight codewords. Therefore, without RankSign the IBE cannot be instantiated at this time. As a second contribution we will show that the problem is deeper than finding a new signature in rank-based cryptography, we also found an attack on the generic problem upon which its security reduction relies. However, contrarily to the RankSign scheme, it seems that the parameters of the IBE scheme could be chosen in order to avoid our attack. Finally, we have also shown that if one replaces the rank metric in the [GHPT17a] IBE scheme by the Hamming metric, then a devastating attack can be found.

Connected through hyperedge HE-1 (induced by source paper "algebraic attacks for solving the rank decoding and minrank problems without gr obner basis"):
  with members:
    - "an algebraic attack on rank metric code based cryptosystems"
    - "improved cryptanalysis of rank metric schemes based on gabidulin codes"
    - "new algorithms for decoding in the rank metric and an attack on the lrpc cryptosystem"
    - "on the complexity of the rank syndrome decoding problem"

Connected through hyperedge HE-2 (induced by source paper "an algebraic attack on rank metric code based cryptosystems"):
  with members:
    - "ranksign an efficient signature algorithm based on the rank metric"
    - "improved cryptanalysis of rank metric schemes based on gabidulin codes"
    - "powers of tensors and fast matrix multiplication"
    - "on the complexity of the rank syndrome decoding problem"

Connected through hyperedge HE-3 (induced by source paper "wave a new family of trapdoor one way preimage sampleable functions based on codes"):
  with members:
    - "ternary syndrome decoding with large weight"
    - "the problem with the surf scheme"
    - "using ldgm codes and sparse syndromes to achieve digital signatures"

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)