During September 2025, Zhengchen Liu enhanced data security in the langgenius/dify repository by developing a full-token masking feature for sensitive tokens. Using Python and applying backend development and security best practices, Liu replaced the previous obfuscation method with a comprehensive masking approach that ensures sensitive values are never partially exposed in logs or the user interface. This targeted update improved privacy compliance and reduced the risk of data leakage, while isolating the changes to minimize disruption to existing workflows. The work demonstrated a focused, in-depth approach to backend security, resulting in safer production data handling and streamlined future audits.