2 research outputs found
A Survey of Layer-Two Blockchain Protocols
After the success of the Bitcoin blockchain, came several cryptocurrencies
and blockchain solutions in the last decade. Nonetheless, Blockchain-based
systems still suffer from low transaction rates and high transaction processing
latencies, which hinder blockchains' scalability. An entire class of solutions,
called Layer-1 scalability solutions, have attempted to incrementally improve
such limitations by adding/modifying fundamental blockchain attributes.
Recently, a completely different class of works, called Layer-2 protocols, have
emerged to tackle the blockchain scalability issues using unconventional
approaches. Layer-2 protocols improve transaction processing rates, periods,
and fees by minimizing the use of underlying slow and costly blockchains. In
fact, the main chain acts just as an instrument for trust establishment and
dispute resolution among Layer-2 participants, where only a few transactions
are dispatched to the main chain. Thus, Layer-2 blockchain protocols have the
potential to transform the domain. However, rapid and discrete developments
have resulted in diverse branches of Layer-2 protocols. In this work, we
systematically create a broad taxonomy of such protocols and implementations.
We discuss each Layer-2 protocol class in detail and also elucidate their
respective approaches, salient features, requirements, etc. Moreover, we
outline the issues related to these protocols along with a comparative
discussion. Our thorough study will help further systematize the knowledge
dispersed in the domain and help the readers to better understand the field of
Layer-2 protocols.Comment: 21 pages, 15 figures, 2 table
SoK: Diving into DAG-based Blockchain Systems
Blockchain plays an important role in cryptocurrency markets and technology
services. However, limitations on high latency and low scalability retard their
adoptions and applications in classic designs. Reconstructed blockchain systems
have been proposed to avoid the consumption of competitive transactions caused
by linear sequenced blocks. These systems, instead, structure
transactions/blocks in the form of Directed Acyclic Graph (DAG) and
consequently re-build upper layer components including consensus, incentives,
\textit{etc.} The promise of DAG-based blockchain systems is to enable fast
confirmation (complete transactions within million seconds) and high
scalability (attach transactions in parallel) without significantly
compromising security. However, this field still lacks systematic work that
summarises the DAG technique. To bridge the gap, this Systematization of
Knowledge (SoK) provides a comprehensive analysis of DAG-based blockchain
systems. Through deconstructing open-sourced systems and reviewing academic
researches, we conclude the main components and featured properties of systems,
and provide the approach to establish a DAG. With this in hand, we analyze the
security and performance of several leading systems, followed by discussions
and comparisons with concurrent (scaling blockchain) techniques. We further
identify open challenges to highlight the potentiality of DAG-based solutions
and indicate their promising directions for future research.Comment: Full versio