# Authentication and Authorization in Microservices Architecture: A Systematic Literature Review
## 3 SLR Results  
This section presents the results of performing the systematic literature review. Figure 1 shows the complete execution process of the proposed protocol to execute the SLR, with the respective quantity of studies identified in each step of the protocol. In the automatic search performed in the digital databases using the initial query, 22 papers were found. These studies were submitted to the snowballing process, resulting in 13 new selected papers. Of the 22 papers found initially, 11 were eliminated due to the exclusion criteria (5 studies that do not address the research object and 6 duplicate). Thus, 11 primary studies were selected from the digital databases and 13 studies on snowballing execution, totaling 24 primary studies. The selected primary studies are shown in Table 1. The filters applied during the SLR based on inclusion and inclusion criteria are demonstrated in Figure 2.  
Figure 1: Protocol application process.  
\begin{table}
\begin{tabular}{l l l l} \hline \hline
**ID** & **Year** & **Title** & **Ref** \\ \hline S1 & 2021 & Security in microservice-based systems: A Multivocal literature review & [4] \\ \hline S2 & 2021 & Security in microservices architectures & [3] \\ \hline S3 & 2020 & Authentication and authorization in microservice-based systems: survey of architecture patterns & [8] \\ \hline S4 & 2020 & Information system development for restricting access to software tool built on microservice architecture & [21] \\ \hline S5 & 2020 & Research on Unified Authentication and Authorization in Microservice Architecture & [22] \\ \hline S6 & 2020 & Secure Edge Computing Management Based on Independent Microservices Providers for Gateway-Centric IoT Networks & [23] \\ \hline S7 & 2019 & Applying Spring Security Framework and OAuth 2.0 To Protect Microservice Architecture API & [24] \\ \hline S8 & 2019 & A survey on security issues in services communication of Microservices-enabled fog applications & [25] \\ \hline S9 & 2019 & Enhancing security to the MicroService (MS) architecture by implementing Authentication and Authorization (AA) service using Docker and Kubernetes & [26] \\ \hline S10 & 2019 & Implementing secure applications in smart city clouds using microservices & [16] \\ \hline S11 & 2019 & Microservice Security Agent Based On API Gateway in Edge Computing & [15] \\ \hline S12 & 2019 & Securing Microservices & [27] \\ \hline S13 & 2019 & Security Mechanisms Used in Microservices-Based Systems: A Systematic Mapping & [28] \\ \hline S14 & 2018 & Authentication and authorization orchestrator for microservice-based software architectures & [29] \\ \hline S15 & 2018 & Defense-in-depth and Role Authentication for Microservice Systems & [30] \\ \hline S16 & 2018 & Fine-Grained Access Control for Microservices & [31] \\ \hline S17 & 2018 & Overcoming Security Challenges in Microservice Architectures & [7] \\ \hline S18 & 2018 & Security considerations for microservice architectures & [32] \\ \hline S19 & 2018 & Unified account management for high performance computing as a service with microservice architecture & [33] \\ \hline S20 & 2017 & A Secure Microservice Framework for IoT & [34] \\ \hline S21 & 2017 & Access control with delegated authorization policy evaluation for data-driven microservice workflows & [35] \\ \hline S22 & 2017 & Authentication and Authorization of End User in Microservice Architecture & [36] \\ \hline S23 & 2017 & Integrating Continuous Security Assessments in Microservices and Cloud Native Applications & [37] \\ \hline S24 & 2015 & Security-as-a-Service for Microservices-Based Cloud Applications & [9] \\ \hline \hline \end{tabular}
\end{table}
Table 1: Selected Studies.