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: "Dual System Encryption: Realizing Fully Secure IBE and HIBE under Simple Assumptions"
  Abstract: We present a new methodology for proving security of encryption systems using what we call Dual System Encryption. Our techniques result in fully secure Identity-Based Encryption (IBE) and Hierarchical Identity-Based Encryption (HIBE) systems under the simple and established decisional Bilinear Diffie-Hellman and decisional Linear assumptions. Our IBE system has ciphertexts, private keys, and public parameters each consisting of a constant number of group elements. These results are the first HIBE system and the first IBE system with short parameters under simple assumptions.

In a Dual System Encryption system both ciphertexts and private keys can take on one of two indistinguishable forms. A private key or ciphertext will be normal if they are generated respectively from the system's key generation or encryption algorithm. These keys and ciphertexts will behave as one expects in an IBE system. In addition, we define semi-functional keys and ciphertexts. A semi-functional private key will be able to decrypt all normally generated ciphertexts; however, decryption will fail if one attempts to decrypt a semi-functional ciphertext with a semi-functional private key. Analogously, semi-functional ciphertexts will be decryptable only by normal private keys.

Dual System Encryption opens up a new way to prove security of IBE and related encryption systems. We define a sequence of games where we change first the challenge ciphertext and then the private keys one by one to be semi-functional. We finally end up in a game where the challenge ciphertext and all private keys are semi-functional at which point proving security is straightforward.

Connected through hyperedge HE-1 (induced by source paper "New chosen-ciphertext secure identity-based encryption with tight security reduction to the bilinear Diffie-Hellman problem"):
  with members:
    (none)

Connected through hyperedge HE-2 (induced by source paper "Fully secure functional encryption with general relations from the decisional linear assumption"):
  with members:
    - "Functional encryption for inner product predicates from learning with errors"
    - "Functional Encryption with Bounded Collusions via Multi-party Computation"
    - "Attribute-Based Encryption for Commercial Content Distribution"

Connected through hyperedge HE-3 (induced by source paper "Collusion resistant broadcast encryption with short ciphertexts and private keys"):
  with members:
    - "Achieving fine-grained access control for secure data sharing on cloud servers"
    - "Public key encryption with conjunctive keyword search and its extension to a multi-user system"
    - "Plutus: Scalable Secure File Sharing on Untrusted Storage"
    - "Conjunctive Broadcast and Attribute-Based Encryption"
    - "Conditional Proxy Broadcast Re-Encryption"
    - "Pairing-Based cryptography at high security levels"
    - "Low Overhead Broadcast Encryption from Multilinear Maps"
    - "Graph-Induced Multilinear Maps from Lattices"

Connected through hyperedge HE-4 (induced by source paper "Functional encryption for inner product predicates from learning with errors"):
  with members:
    - "Fully secure functional encryption with general relations from the decisional linear assumption"
    - "Conjunctive Broadcast and Attribute-Based Encryption"
    - "Computing Blindfolded: New Developments in Fully Homomorphic Encryption"
    - "Candidate Indistinguishability Obfuscation and Functional Encryption for all Circuits"
    - "Constructing Subspace Membership Encryption through Inner Product Encryption"

Connected through hyperedge HE-5 (induced by source paper "Achieving fine-grained access control for secure data sharing on cloud servers"):
  with members:
    - "Collusion resistant broadcast encryption with short ciphertexts and private keys"
    - "Building access control policy model for privacy preserving and testing policy conflicting problems"

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