human: Given a node-centered hypergraph: <hypergraph>, where nodes represent authors and hyperedges represent groups of authors who co-authored the same paper.

Details of the hypergraph:
Center node: "Rational Secure Two-party Computation in Social Cloud"
  Abstract: Rational parties in secure two-party computation (STPC) are willing to maximize their utilities. However, they have no incentives to cooperate in STPC under correctness and exclusivity assumptions since cooperation will bring them inferior utilities. Consequently, both parties will not participate in STPC. Therefore, new methods must be introduced to make parties cooperate such that they can complete this computation task. In this paper, we redefine utility considering the notion of reputation derived from social cloud to promote cooperation. In social cloud, parties form their reputation when they interact with others. Parties will get a higher utility if they have a higher cooperative reputation. Therefore they have incentives to cooperate. The computation of reputation is completed in the social cloud, which reduce the computation work for parties. Furthermore, we prove that given proper parameters in rational STPC, it is possible to construct an efficient computation protocol, where only one exchanging round in the second stage of the hybrid protocol.

Connected through hyperedge HE-1 (induced by source paper "More Efficient Constant-Round Multi-party Computation from BMR and SHE"):
  with members:
    - "Authenticating Computation on Groups: New Homomorphic Primitives and Applications"
    - "A Secure Obfuscator for Encrypted Blind Signature Functionality"
    - "On Obfuscation with Random Oracles"
    - "Graph-Induced Multilinear Maps from Lattices"
    - "Blazing Fast 2PC in the Offline/Online Setting with Security for Malicious Adversaries"
    - "Non-Interactive Secure Computation Based on Cut-and-Choose"
    - "Efficient Secure and Verifiable Outsourcing of Matrix Multiplications"
    - "An Efficient Transform from Sigma Protocols to NIZK with a CRS and Non-programmable Random Oracle"

Question: Please tell me which research area the center author belongs to. The 4 classes are: Computer science, Mathematics, Engineering, Economics, Psychology, Business. Directly output the class name.

gpt: Computer science