Abstract: Information assets recognition and its importance assessment is a key step in information security assessments. This paper proposes a method based on information flow to give a solution. Firstly, we use Petri Nets theory to analyze the business process, it is beneficial for us to recognize assets' nodes and transform all information assets into a directed graph. Secondly, combined with classified protection of information system, an algorithm called FrequencyRank is put forward to calculate the value of each node in the directed graph, the value of each node represents its importance in the graph. Experiments show that the solution in this paper can accurately get the importance of each node, and also it is consistent with the actual situation.

Key words: assets recognition, importance assessment, Petri Nets, FrequencyRank algorithm, classified protection