# On Data Leakage Prevention Maturity: Adapting the C2M2 Framework
## 2 Materials and Methods
### Literature Research
#### 2.3.1 DLP Literature Review  
A meticulous literature review was conducted with the primary objective of obtaining a profound understanding of DLP. This deep comprehension is essential for the development of a DLP Maturity Model, as it lays the groundwork for identifying and integrating the critical elements that define the maturity of DLP practices and technologies.  
DLP represents a mature area of inquiry, characterized by a significant accumulation of research. This existing body of work necessitates a structured approach to literature review, as advocated by [PERSON] and [PERSON] [41].  
The initial step in this structured approach involved querying knowledge databases using specific search terms, as detailed in Table 1. This process ensured that the literature review was comprehensive and aligned with our research objectives. Following this initial step, our focus was directed towards grasping the broader landscape of DLP, rather than delving into niche topics. With the aim of ensuring that the review encapsulated widely recognized and influential studies, we made a deliberate decision to exclude results that had five or fewer citations. This criterion was applied to concentrate our efforts on contributions that have garnered academic attention and have thus played a substantial role in shaping the understanding of the DLP domain.  
Subsequently, we undertook the task of removing duplicates, thus refining our collection of sources. This step was critical for maintaining the quality and relevance of the literature under review, enabling a focused examination of the field that supports the construction of a robust DLP Maturity Model. We imposed several additional constraints to align more closely with our research focus and to ensure the relevance and quality of the sources considered. Firstly, we opted to exclude studies related to blockchain technologies. Despite the growing interest in this area, there is a discernible absence of practical, implementable proof-of-concept projects within the entire cybersecurity domain utilizing this technology. Furthermore, we disregarded ideas and theories presented without a prototype and those of a purely speculative nature. Additionally, any literature that did not demonstrate relevance for the practical application of DLP was omitted. This included highly technical works that delved into specifics such as highly sophisticated exfiltration techniques. Lastly, topics centered on key management, access management, and digital rights management (DRM) were also set aside. While these areas are crucial to the broader field of information and access management (IAM), they do not directly address the nuances of detecting policy violations.  
Through these judicious exclusions, our literature review concentrated on sources that offer substantive contributions to the understanding and advancement of DLP, ensuring that our research is both comprehensive and focused. After applying these criteria, 51 papers were reviewed.  
In line with best practices in conducting literature reviews [41, 43], a backward search was conducted, yielding over 900 additional papers. The same stringent criteria previously outlined were applied to these findings. Ultimately, this rigorous selection process culminated in a consolidated corpus of 128 papers, forming the foundation upon which the insights presented in this work are based.  
Initial attempts to organize the findings within a Concept Matrix (as proposed by [41, 43]) were not conducive to selecting an appropriate maturity framework. Therefore, we shifted our strategy to employ a concept graph, a method supported by both [PERSON] et al. [44] and [PERSON] and [PERSON]. [45], to better synthesize and visualize the research outcomes. Figure 2 shows this process, providing a comprehensive visual summary of the knowledge synthesized.