Which masking rule uses a set of dictionary files located in the agent installation directory?

Substitution Masking is the correct choice as it utilizes a set of dictionary files located in the agent installation directory. This masking technique replaces sensitive data with similar-looking or contextually accurate data from these dictionaries, ensuring that the masked values resemble real data while providing a strong level of data protection. By leveraging pre-defined terms or phrases stored in dictionary files, this method enables consistent and contextually relevant data replacement.

Key Masking, Random Masking, and Pattern Masking, while also valid masking techniques, do not specifically rely on dictionary files. Key Masking generally replaces data based on a cryptographic key, Random Masking generates random values without reference to a dictionary, and Pattern Masking adheres to predefined patterns without using a dictionary for substitutions. This distinction highlights why Substitution Masking is aligned with the use of dictionary files for its functionality.