A Survey of Consortium Blockchain and Its Applications

Abstract

Blockchain is a revolutionary technology that has reshaped the trust model among mutually distrustful peers in a distributed network. While blockchain is well-known for its initial usage in a public manner, such as the cryptocurrency of Bitcoin, consortium blockchain, which requires authentication of all involved participants, has also been widely adopted in various domains. Nevertheless, there is a lack of comprehensive study of consortium blockchain in terms of its architecture design, consensus mechanisms, comparative performance, etc. In this study, we aim to fill this gap by surveying the most popular consortium blockchain platforms and assessing their core designs in a layered fashion. Particularly, Byzantine fault tolerant (BFT) state machine replication (SMR) is introduced to act as a basic computational model of consortium blockchain. Then the consortium blockchain is split into the hardware layer, layer-0 (network layer), layer-I (data layer, consensus layer and contract layer), layer-II protocols, and application layer. Each layer is presented with closely related discussion and analysis. Furthermore, with the extraction of the core functionalities, i.e., robust storage and guaranteed execution, that a consortium blockchain can provide, several typical consortium blockchain-empowered decentralized application scenarios are introduced. With these thorough studies and analyses, this work aims to systematize the knowledge dispersed in the consortium blockchain, highlight the unsolved challenges, and also indicate the propitious avenues of future work.

Blockchain and Smart Contracts for Digital Copyright Protection

“…where x, x, and b maintain the signification reported above, while f (x) and ∆(x) denote a function of the original signal features and a signal-dependent quantization step, respectively [1,42]. Therefore, by directly operating in the encrypted domain, the watermark insertion can be obtained by applying the following expression [37,46,47]: In the first implementations documented in [16,17], the adopted blockchain is classified as "public", with a fully decentralized architecture, and is based on the "proof of work" (PoW) consensus algorithm [10][11][12]. Its nodes are implemented in Ethereum [49], whereas the smart contracts are coded in Solidity [50].…”

“…The first aspect to intervene in is the removal of WCAs without reducing the usability of the protocols. To this end, solutions can be found in the field of blockchains used to protect digital copyright [10][11][12].…”