Research

Blockchain has come a long way - a system that was initially proposed specifically for cryptocurrencies is now being adapted and adopted as a general-purpose transactional system. As blockchain evolves into another data management system...

With the emergence of hybrid blockchain database systems, we aim to provide an in-depth analysis of the performance and trade-offs among a few representative systems. To achieve this goal, we implement Veritas and BlockchainDB from scratch....

We present LedgerView -- a system that adds access control views to permissioned blockchains. The approach is motivated by an AT&T application of tracking refurbished devices. A blockchain is a decentralized tamper-resistant ledger managed by a group of peers....

In the Metaverse, the physical space and the virtual space co-exist, and interact simultaneously. While the physical space is virtually enhanced with information, the virtual space is continuously refreshed with real-time, real-world information. To allow users to process and manipulate information seamlessly between the real and digital spaces, novel technologies must be developed. ...

Verifiable ledger databases protect data history against malicious tampering. Existing systems, such as blockchains and certificate transparency, are based on transparency logs --- a simple abstraction allowing users to verify that a log maintained by an untrusted server is append-only. ...

This paper presents a systematic and comprehensive survey on blockchain interoperability, where interoperability is defined as the ability of blockchains to flexibly transfer assets, share data, and invoke smart contracts across a mix of public, private, and consortium blockchains without any changes to the underlying blockchain systems. ...

Vertical federated learning (VFL) is an emerging paradigm for cross-silo organizations to build more accurate machine learning (ML) models. In this setting, multiple organizations (i.e., parties) hold the same set of samples with different features....

Blockchain-like ledger databases emerge in recent years as a more efficient alternative to permissioned blockchains. Conventional ledger databases mostly rely on authenticated structures such as the Merkle tree and transparency logs for supporting auditability, and hence they suffer from the performance problem....

Database systems are paying more attention to data security in recent years. Immutable systems such as blockchains, verifiable databases, and ledger databases are equipped with various verifiability mechanisms to protect data....

In this paper, we propose the Blockchain Benchmark Standardized Format (BBSF), a framework for standardized, transparent, and fair benchmarks for blockchains. BBSF enables users and developers to compare blockchain platforms using metrics derived from realistic workloads....

In the last decade, blockchain technologies have entered the enterprise space in the form of permissioned blockchains, verifiable databases, and hybrid blockchain database systems (HBDB). The core of these blockchain technologies is represented by cryptography operations such as secure hashing typically with SHA-3 algorithms...

This book takes readers through the sensational history of blockchains and their potential to revolutionize database systems of the future. In order to demystify blockchains, the book capitalizes on decades of research and field testing of existing database and distributed systems and applies these familiar concepts to the novel blockchain system.

In a traditional enterprise information system, the database is the final source of truth. The data in the database are closely guarded by access controls and integrity checking. Privacy regulations often apply to the use of data (examples include the U.S. HIPPA and FERPA regulations for health and education records respectively).