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 "secure beamforming for mimo two way communications with an untrusted relay"):
  Abstract: This paper studies the secure beamforming design in a multiple-antenna three-node system where two source nodes exchange messages with the help of an untrusted relay node. The relay acts as both an essential signal forwarder and a potential eavesdropper. Both two-phase and three-phase two-way relay strategies are considered. Our goal is to jointly optimize the source and relay beamformers for maximizing the secrecy sum rate of the two-way communications. We first derive the optimal relay beamformer structures. Then, iterative algorithms are proposed to find source and relay beamformers jointly based on alternating optimization. Furthermore, we conduct asymptotic analysis on the maximum secrecy sum-rate. Our analysis shows that when all transmit powers approach infinity, the two-phase two-way relay scheme achieves the maximum secrecy sum rate if the source beamformers are designed such that the received signals at the relay align in the same direction. This reveals an important advantage of signal alignment technique in against eavesdropping. It is also shown that if the source powers approach zero, the three-phase scheme performs the best while the two-phase scheme is even worse than direct transmission. Simulation results have verified the efficiency of the proposed secure beamforming algorithms as well as the analytical findings.

Includes members:
  Member "secure communication via an untrusted non regenerative relay in fading channels":
    also connected through other hyperedges:
      - Hyperedge HE-1 (induced by source paper "enhancing physical layer security in af relay assisted multicarrier wireless transmission enhancing physical layer security in af relay assisted multicarrier wireless transmission")
  Member "joint source and relay precoding designs for mimo two way relaying based on mse criterion":
    also connected through other hyperedges:
      - Hyperedge HE-2 (induced by source paper "utility energy efficiency oriented user association with power control in heterogeneous networks")
  Member "relay placement for physical layer security a secure connection perspective":
    also connected through other hyperedges:
      - Hyperedge HE-3 (induced by source paper "link selection for secure cooperative networks with buffer aided relaying")
  Member "joint relay and jammer selection for secure two way relay networks":
    also connected through other hyperedges:
      - Hyperedge HE-4 (induced by source paper "secure transmission and self energy recycling with partial eavesdropper csi")
  Member "cooperative jamming for secure communications in mimo relay networks":
    also connected through other hyperedges:
      - Hyperedge HE-5 (induced by source paper "multi antenna jamming in covert communication")
  Member "cooperation with an untrusted relay a secrecy perspective":
    also connected through other hyperedges:
      - Hyperedge HE-6 (induced by source paper "secure relaying in non orthogonal multiple access trusted and untrusted scenarios")
  Member "two hop secure communication using an untrusted relay":
    also connected through other hyperedges:
      - Hyperedge HE-7 (induced by source paper "group secret key generation using algebraic rings in three user wireless networks")
  Member "optimal beamforming for two way multi antenna relay channel with analogue network coding":
    also connected through other hyperedges:
      - Hyperedge HE-8 (induced by source paper "optimization of a power splitting protocol for two way multiple energy harvesting relay system")

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.IT(Information Theory)