data-mask-studio

Data Mask Studio (DMS) is an open-source, local-first desktop application for Windows 10/11 that provides data preparation, anonymization, and deterministic data masking workflows. Built with Python 3.12+ and PySide6, it processes CSV files individually or in batches using saved profiles, and can restore masked data from CSV files as well as codes found in local HTML files and dashboards. Key capabilities include selective column preservation, masking, or exclusion; value normalization; output header renaming; column composition; and assisted column detection. Masking is deterministic and tied to an encrypted local vault (SQLite with AES-256-GCM), where local keys are protected by Windows DPAPI. The vault enables controlled restoration of original values from generated tokens, which do not directly expose the original data. Additional features include password-protected portable backups, integrity auditing, diagnostics and maintenance tools, streaming processing for large files, and fully local operation without telemetry. The 1.0.x series maintains token compatibility with schema 3 and supports transactional migration of older vaults. The application is distributed under GPL-3.0-only as a per-user Windows installer or a portable package. It currently targets Windows only due to its reliance on DPAPI, and executables are not yet digitally signed. There is no synchronization, automatic updating, or remote key recovery.