Blockchain Technology

PETR NOVOTNY
IBM T.J. Watson Research Center

ELAINE (RUNTING) SHI
Cornell University

Since its conception by Satoshi Nakamoto in 2008 and first implementation in Bitcoin, the popularity of blockchain and interest in it are rapidly accelerating. As the technology that underlies implementation of Bitcoin and other applications, blockchain is designed as a decentralized network of peers who collectively share and manage a distributed ledger structured as a series of ordered and cryptographically connected blocks, each containing a list of transactions. New transactions are created by smart contracts that embody an application-specific logic (e.g., the transfer of money between accounts or creation of a shipping record). Before inclusion in the ledger, new transactions and blocks must be approved by the network participants through a consensus mechanism. Once included in the distributed ledger, the transactions are immutable, timestamped, and retrospectively verifiable by any network participant. With the use of these mechanisms, blockchain provides data availability, transparency, and digital trust unparalleled by other systems.

The initial Bitcoin network inspired many new blockchain applications with extended capabilities and uses in a range of areas. However, despite advances in recent years, many fundamental challenges remain unresolved and are the subject of intense scientific research and technology development. Additionally, the trust that blockchain provides opens new opportunities for applications in governance and economy as well as social, healthcare, and other sectors that are being actively investigated.

In this session, Elaine Shi introduced the history and key concepts of blockchain and provided an overview of the major platforms and applications, including

Bitcoin, Ethereum, and Hyperledger.¹ Next, Hong Wan (North Carolina State University) discussed the domain of private and permissioned blockchain platforms, such as Hyperledger Fabric and Corda, designed as building blocks of networks among consortiums of enterprises, as well as the advantages, threads, and weaknesses of these platforms. This talk was followed by Jacob Leshno (University of Chicago), who discussed the use of blockchain technologies in cryptocurrencies.

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¹ Paper not included in this volume.