{"id":3427,"date":"2019-05-04T22:30:46","date_gmt":"2019-05-04T20:30:46","guid":{"rendered":"https:\/\/blog.iese.fraunhofer.de\/?p=3427"},"modified":"2024-02-07T08:40:46","modified_gmt":"2024-02-07T07:40:46","slug":"architecting-blockchain-based-applications-2-what-do-you-really-mean-by-blockchain","status":"publish","type":"post","link":"https:\/\/www.iese.fraunhofer.de\/blog\/architecting-blockchain-based-applications-2-what-do-you-really-mean-by-blockchain\/","title":{"rendered":"What Do You Really Mean by \u201cBlockchain\u201d? – Architecting Blockchain-Based Applications (2\/3)"},"content":{"rendered":"

Blockchain is a heavily overloaded term, both in discussions of practitioners and in literature. This ambiguity is dangerous as it leads to a lot of misunderstandings and can compromise the quality of blockchain-based applications being developed. Thus, we delineate in this article key terms of blockchain. To make understanding as simple as possible, we use Ethereum as an example.<\/p>\n

\u2460Needs<\/a> | \u2460Foundations<\/a> | \u2461Ambiguous Terminology<\/a> | \u2461Consistent Terminology<\/a> | \u2462Architecting Guidance<\/a> | \u2462Get Started<\/a><\/p>\n

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This article is the second of a three-article series (\u2460<\/a>\u2461\u2462<\/a>) on architecting blockchain-based applications. The series is based on results of an internal workshop of our department ACE (Architecture-Centric Engineering) in 2018.<\/p>\n

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Authors (main editors underlined): Susanne Braun, Frank Elberzhager, Matthias Gerbershagen, Andreas Giloj, Sebastian Heupts, Steffen Hupp, Alberto Lara, Rodrigo Falc\u00e3o<\/u>, Matthias Naab<\/u>, Kai Plociennik<\/u>, Bernd Rauch, Dominik Rost, Johannes C. Schneider<\/u>, Stefan Schweitzer, Adeline Silva Sch\u00e4fer, Balthasar Weitzel.<\/p>\n

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If you want to develop innovative ideas, architectures, and prototypes of applications based on blockchain technologies: Don\u2019t hesitate to contact us!<\/p>\n<\/div>\n

In our first article of our article series on architecting blockchain-based applications, we outlined the need for precise blockchain terminology. We want to start by giving some concrete examples on that claim.<\/p>\n

Ambiguous Blockchain Terminology in Literature and Practice and Why It Is Dangerous<\/h2>\n

We found a lot of ambiguity of terminology around blockchain in discussions with practitioners. Even worse, when looking at present (scientific and practical) literature covering different aspects of blockchain-based applications and technology, different forms of confusion can be observed. Since Bitcoin was the first cryptocurrency, in particular non-technical people often mix up the terms Bitcoin and Blockchain. \u00a0Due to this, IBM published a clarifying blog article<\/a> on that topic. Furthermore, while scientific papers correctly distinguish between general blockchain topics and those specific to concrete blockchain technologies such as Bitcoin and Ethereum, the scope of the term \u201cblockchain\u201d can vary dramatically, from the \u201cpure\u201d blockchain data structure (\u201cwe use blockchain to refer to the data structure\u201d, Xu, Pautasso et al.<\/a>) to a complex distributed system with applications that communicate via a network using blockchain technology (\u201cA blockchain is a network of a set of peer-to-peer nodes\u201d, Kan et al.<\/a>). This observation has been made by several others, too: Swan notes that \u201cthe terminology can be confusing<\/a> because the words Bitcoin and blockchain may be used to refer to any three parts of the concepts: the underlying blockchain technology, the protocol and client through which transactions are effected, and the actual cryptocurrency; or also broadly to refer to the whole concept of cryptocurrencies.\u201d. Xu, Weber et al. write that \u201cthe term \u2018blockchain\u2019 is used to refer to a data structure and occasionally to a network or system\u201d<\/a>. And Kramer et al. state that \u201cthe term \u2018blockchain\u2019 is overloaded<\/a> and can be referred to as either the generic architectural pattern that was popularized by its application in the digital peer-to-peer currency Bitcoin, or to the actual instantiation of the pattern as applied in projects such as Bitcoin and Ethereum\u201d. Although in the latter references, the authors specify the scope of the term \u201cblockchain\u201d in their work, there is no common understanding between different publications, and many authors use terms like \u201cblockchain technology\u201d, \u201cblockchain network\u201d, \u201cblockchain instance\u201d, \u201cblockchain node\u201d, \u201cblockchain data structure\u201d, \u201cblockchain architectural pattern\u201d, \u201cblockchain system\u201d, or \u201cblockchain applications\u201d without explicitly defining these terms, not even within their context.<\/p>\n

These examples illustrate that the term \u201cblockchain\u201d is ambiguous and overloaded. In this lack of precision, we see a fundamental problem for the work of software engineers and in particular software architects. To be able to use such a technology in the design of applications, they need a consistent and precise terminology, to be able to understand the extent of their solution space, reason about design alternatives, predict the resulting system properties, discuss with other software engineers, and make according, well-founded decisions. These decisions constitute an architecture, which has to be documented and communicated to the various stakeholders involved in the realization of software applications. Not being able to do so because of ambiguities in the terminology is dangerous because it makes the work of the involved stakeholders less efficient and causes errors, which may even prevent the fulfillment of architecture drivers.<\/p>\n

This is particularly problematic in the context of blockchain-based applications. The technology is new and evolves quickly, and the number of existing real-world applications is limited. As a result, documentation only exists sparsely and is often either very high-level and abstract or very low-level and technical. Hence, software engineers cannot rely on strong experience from the community in developing such applications. In such scenarios, the risk of introducing errors and making wrong decisions due to misunderstandings is particularly high. As trust is a key attribute for blockchain-based applications, the consequences of mistakes can be particularly severe.<\/p>\n

A Consistent Blockchain Terminology<\/h2>\n

We propose a terminology precisely delineating terms around blockchain<\/strong>, to reduce ambiguity<\/strong> of terms and to avoid misunderstandings<\/strong> in discussions. Thus, we focus on terms, which we found often not clearly delineated in research and in practice. To<\/p>\n

We use Ethereum as an example<\/strong> for our explanations to make it simpler, but most of the terms are directly transferrable to other blockchain technologies.<\/p>\n