**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.

### **Table 1.** Selected Studies.


**Figure 2.** Filters applied in SLR process.

### *3.1. Quality Assessment of Reviews Carried out*

According to the quality criteria, the selected studies were analyzed and scored, as shown in Table 2. All primary studies mentioned challenges involving authorization and authentication in microservices (AQ3), as well as mechanisms to mitigate such problems (AQ4), even if partially. However, there is a smaller amount of work (15) mentioning open-source technologies that implement the mechanism (AQ5). In general, the studies are clear about the objective (AQ1), but 11 of them do not describe its limitations (AQ2).


**Table 2.** Ranking of scores according to Quality Assessments.
