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: "Provable data possession at untrusted stores"
  Abstract: We introduce a model for  provable data possession  (PDP) that allows a client that has stored data at an untrusted server to verify that the server possesses the original data without retrieving it. The model generates probabilistic proofs of possession by sampling random sets of blocks from the server, which drastically reduces I/O costs. The client maintains a constant amount of metadata to verify the proof. The challenge/response protocol transmits a small, constant amount of data, which minimizes network communication. Thus, the PDP model for remote data checking supports large data sets in widely-distributed storage system.   We present two provably-secure PDP schemes that are more efficient than previous solutions, even when compared with schemes that achieve weaker guarantees. In particular, the overhead at the server is low (or even constant), as opposed to linear in the size of the data. Experiments using our implementation verify the practicality of PDP and reveal that the performance of PDP is bounded by disk I/O and not by cryptographic computation.

Connected through hyperedge HE-1 (induced by source paper "Plutus: Scalable Secure File Sharing on Untrusted Storage"):
  with members:
    - "Collusion resistant broadcast encryption with short ciphertexts and private keys"
    - "Proactive recovery in a Byzantine-fault-tolerant system"

Connected through hyperedge HE-2 (induced by source paper "Proofs of ownership in remote storage systems"):
  with members:
    - "A Secure Data Deduplication Scheme for Cloud Storage"

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