## 2 Survey Methodology  
We performed a survey in a very systematic way by identifying top research findings in the domain of blockchain-based supply chain management (BC-SCM). We extracted information and summarised the current literature according to the guidelines suggested by [PERSON] [4; 5]. Our approach follows a defined sequence of steps using a systematic literature review (SLR) [6], started from downloading related research articles, reports, thesis, and industrial tools using keyword-based query-searching mentioned in Table 1. At the initial stage of the study, we found that industries played a major role in identifying the role of blockchain for supply chain management, while developing tools based on the blockchain technology. Therefore, we partitioned our survey into industrial efforts and academic efforts. Industrial efforts particularly focus on the development of blockchain-based tools for supply chain management. On the other hand, the academic efforts are the published research literature, focusing on the research aspects of the blockchain technology for supply chain processes.  
The security of communication and computation operations is the major concern of any blockchain system. On this account, research questions are defined based on the existing solutions to communication and computational attacks on supply chain systems to identify the research gaps and opportunities through a designed framework. Mainly, following research questions are investigated in this study.  
* What is the blockchain technology and how it is used for a supply chain system?
* The use of smart contracts for a blockchain-based supply chain system?
* What is the security requirement for a supply chain system and what are major computation and communication attacks that compromises the security of a blockchain-based supply chain system?
* What efforts had been made by the industrial sector-in terms of tools development- to handle existing computation and communication attacks by introducing secure blockchain system?
* What research solutions had been achieved by the academia to cater computation and communication attacks on a blockchain-based supply chain system?
* What are the current research gaps and future potentials for the academia and the industry to focus on?
* What are the main aspects that must be considered while designing a blockchain-based supply chain system (recommendations)?  
To widely cover the current literature, we considered studies published in five multidisciplinary electronic bibliographic database including IEEE, ACM, Springer, Elsevier, and ScienceDirect. Since the blockchain technology is recently become popular, it started to be used for supply chain management in last decade. Therefore, we considered articles published from 2015-2020. Even though, we found more than 30,000 blockchain related studies, we selected top 150 studies that matches our search criteria in Table 1. Downloaded articles were critically examined based on the research questions and related abstracts, and half of the papers were excluded in this phase. During full-text screening and Snowball sampling, 20 more papers are eliminated. Backward and forward selection is performed on references of the remaining 55 papers, identifying 7 more potential papers. In addition to research articles and thesis, 29 web-reports and industrial tools are pointed out in this study. Figure 1 shows the number of studies considered from each year, from 2015 to 2020.