About Me

I am a senior software developer at Fortinet. Previously, I was a visiting post-doctoral research fellow in the School of Computing Science at Simon Fraser University working with Prof. Jian PEI. I obtained my Ph.D. degree from the Computer Science Department at Hong Kong Baptist University, advised by Prof. Jianliang XU. I was a member of the Database Group and the Blockchain & FinTech Lab. Prior to that, I obtained my Bachelor degree from the School of Electronic Information and Communications, Huazhong University of Science and Technology.

Research Interests

I am interested in Databases, Blockchain, Cryptography, Information Security, and Privacy-Aware Computing. My current focuses include:

• Authenticated query processing for outsourcing cloud computing.
• Searchable blockchain with integrity assurance.
• Privacy preserving query processing and access control.

Publications [Google Scholar] [DBLP]

• X. Zhang, Q. Wang, C. Xu, Y. Peng, and J. Xu, “FedKNN: Secure Federated k-Nearest Neighbor Search,” in Proceedings of the 2024 ACM SIGMOD International Conference on Management of Data (SIGMOD ’24), Santiago, Chile, 2024. Full Paper.
• X. Luo, J. Pei, C. Xu, W. Zhang, and J. Xu, “Fast Shapley Value Computation in Data Assemblage Tasks as Cooperative Simple Games,” in Proceedings of the 2024 ACM SIGMOD International Conference on Management of Data (SIGMOD ’24), Santiago, Chile, 2024. Full Paper.
• Y. Ji, C. Xu, C. Zhang, and J. Xu, “DCert: Towards Secure, Efficient and Versatile Blockchain Light Clients,” in Proceedings of the 23rd ACM/IFIP International Middleware Conference (Middleware ’22), Quebec, QC, Canada, 2022, doi: 10.1145/3528535.3565250. Full Paper. [pdf] [eprint]
• X. Luo, J. Pei, Z. Cong, and C. Xu, “On Shapley Value in Data Assemblage Under Independent Utility,” Proceedings of the VLDB Endowment (PVLDB), vol. 15, no. 11, pp. 2761–2773, Jul. 2022, doi: 10.14778/3551793.3551829. Full Paper. [pdf] [eprint] [slides] [poster] [code]
• H. Wang, C. Xu, C. Zhang, J. Xu, Z. Peng, and J. Pei, “vChain+: Optimizing Verifiable Blockchain Boolean Range Queries,” in Proceedings of the 38th IEEE International Conference on Data Engineering (ICDE ’22), Kuala Lumpur, Malaysia, 2022, pp. 1928–1941, doi: 10.1109/ICDE53745.2022.00190. Full Paper. [pdf] [eprint] [tech. report] [code]
• C. Xu, C. Zhang, J. Xu, and J. Pei, “SlimChain: Scaling Blockchain Transactions through Off-Chain Storage and Parallel Processing,” Proceedings of the VLDB Endowment (PVLDB), vol. 14, no. 11, pp. 2314–2326, Jul. 2021, doi: 10.14778/3476249.3476283. Full Paper. [pdf] [eprint] [tech. report] [slides] [poster] [video] [code]
• Z. Peng, C. Xu, H. Wang, J. Huang, J. Xu, and X. Chu, “P²B-Trace: Privacy-Preserving Blockchain-based Contact Tracing to Combat Pandemics,” in Proceedings of the 2021 ACM SIGMOD International Conference on Management of Data (SIGMOD ’21), Xi'an, Shaanxi, China, 2021, pp. 2389–2393, doi: 10.1145/3448016.3459237. Short Paper. [pdf] [eprint] [video]
• C. Zhang, C. Xu, H. Wang, J. Xu, and B. Choi, “Authenticated Keyword Search in Scalable Hybrid-Storage Blockchains,” in Proceedings of the 37th IEEE International Conference on Data Engineering (ICDE ’21), Chania, Crete, Greece, 2021, pp. 996–1007, doi: 10.1109/ICDE51399.2021.00091. Full Paper. [pdf] [eprint] [slides]
• K. Li, Y. Tang, J. Chen, Z. Yuan, C. Xu, and J. Xu, “Cost-Effective Data Feeds to Blockchains via Workload-Adaptive Data Replication,” in Proceedings of the 21st ACM/IFIP International Middleware Conference (Middleware ’20), Delft, Netherlands, 2020, pp. 371–385, doi: 10.1145/3423211.3425696. Full Paper. [pdf]
• H. Wang, C. Xu, C. Zhang, and J. Xu, “vChain: A Blockchain System Ensuring Query Integrity,” in Proceedings of the 2020 ACM SIGMOD International Conference on Management of Data (SIGMOD ’20), Portland, OR, USA, 2020, pp. 2693–2696, doi: 10.1145/3318464.3384682. Demo Paper. [pdf] [eprint] [video] [code]
• S. Guo, Y. Ji, C. Zhang, C. Xu, and J. Xu, “vCBIR: A Verifiable Search Engine for Content-Based Image Retrieval,” in Proceedings of the 36th IEEE International Conference on Data Engineering (ICDE ’20), Dallas, TX, USA, 2020, pp. 1730–1733, doi: 10.1109/ICDE48307.2020.00156. Demo Paper. [pdf]
• C. Xu, C. Zhang, and J. Xu, “vChain: Enabling Verifiable Boolean Range Queries over Blockchain Databases,” in Proceedings of the 2019 ACM SIGMOD International Conference on Management of Data (SIGMOD ’19), Amsterdam, Netherlands, 2019, pp. 141–158, doi: 10.1145/3299869.3300083. Full Paper. [pdf] [eprint] [slides] [poster] [code]
• Y. Ji, C. Xu, J. Xu, and H. Hu, “vABS: Towards Verifiable Attribute-Based Search over Shared Cloud Data,” in Proceedings of the 35th IEEE International Conference on Data Engineering (ICDE ’19), Macau SAR, China, 2019, pp. 2028–2031, doi: 10.1109/ICDE.2019.00231. Demo Paper. [pdf] [eprint] [poster]
• S. Guo, J. Xu, C. Zhang, C. Xu, and T. Xiang, “ImageProof: Enabling Authentication for Large-Scale Image Retrieval,” in Proceedings of the 35th IEEE International Conference on Data Engineering (ICDE ’19), Macau SAR, China, 2019, pp. 1070–1081, doi: 10.1109/ICDE.2019.00099. Full Paper. [pdf] [eprint] [slides] [poster]
• C. Zhang, C. Xu, J. Xu, Y. Tang, and B. Choi, “GEM²-Tree: A Gas-Efficient Structure for Authenticated Range Queries in Blockchain,” in Proceedings of the 35th IEEE International Conference on Data Engineering (ICDE ’19), Macau SAR, China, 2019, pp. 842–853, doi: 10.1109/ICDE.2019.00080. Full Paper. [pdf] [eprint] [slides] [poster]
• C. Xu, J. Xu, H. Hu, and M. H. Au, “When Query Authentication Meets Fine-Grained Access Control: A Zero-Knowledge Approach,” in Proceedings of the 2018 ACM SIGMOD International Conference on Management of Data (SIGMOD ’18), Houston, TX, USA, 2018, pp. 147–162, doi: 10.1145/3183713.3183741. Full Paper. [pdf] [eprint] [slides] [poster]
• C. Zhang, C. Xu, J. Xu, and B. Choi, “Distributed kNN Query Authentication,” in Proceedings of the 19th IEEE International Conference on Mobile Data Management (MDM ’18), Aalborg, Denmark, 2018, pp. 167–176, doi: 10.1109/mdm.2018.00034. Full Paper. [pdf] [eprint]
• C. Xu, Q. Chen, H. Hu, J. Xu, and X. Hei, “Authenticating Aggregate Queries over Set-Valued Data with Confidentiality,” IEEE Transactions on Knowledge and Data Engineering (TKDE), vol. 30, no. 4, pp. 630–644, Apr. 2018, doi: 10.1109/TKDE.2017.2773541. Full Paper. [pdf] [eprint] [poster]
• C. Xu, Q. Chen, H. Hu, J. Xu, and X. Hei, “Authenticating Aggregate Queries over Set-Valued Data with Confidentiality (Extended Abstract),” in Proceedings of the 34th IEEE International Conference on Data Engineering (ICDE ’18), Paris, France, 2018, pp. 1797–1798, doi: 10.1109/ICDE.2018.00256. Poster Paper. [pdf] [eprint] [poster]
• Y. Tang, Z. Xing, C. Xu, J. Chen, and J. Xu, “Lightweight Logging over the Blockchain for Data-Intensive Applications,” in 2nd Workshop on Trusted Smart Contracts at International Conference on Financial Cryptography and Data Security, Santa Barbara Beach Resort, Curaçao, 2018, pp. 308–324, doi: 10.1007/978-3-662-58820-8_21. Workshop Paper. [pdf]
• Q. Zhu, H. Hu, C. Xu, J. Xu, and W.-C. Lee, “Geo-social group queries with minimum acquaintance constraints,” The VLDB Journal (VLDBJ), vol. 26, no. 5, pp. 709–727, Jul. 2017, doi: 10.1007/s00778-017-0473-6. Full Paper. [pdf] [eprint] [poster]

Talks

• Blockchain Privacy Preserving Techniques, The 36th CCF National Database Conference, Jinan, China, Oct. 12, 2019. [link] [slides]
• Towards Searchable and Verifiable Blockchain, 1st Workshop on Blockchain and Data Management at 35th IEEE International Conference on Data Engineering, Macau, Apr. 8, 2019. [link] [slides]
• When Query Authentication Meets Fine-Grained Access Control: A Zero-Knowledge Approach, 2018 ACM SIGMOD International Conference on Management of Data, Houston, TX, USA, Jun. 12, 2018. [link] [slides]