Mask in bulk.
Restore with evidence.

PrivaMask is a local data masking tool for Windows: batch-process sensitive data in Excel, CSV and Word files.

Everything happens on your computer — no network, no upload, no telemetry.

✔ 100% local, zero upload ✔ xls · xlsx · csv · doc · docx ✔ Mask + fake-data modes ✔ Position-level restore ✔ Mapping export
Free download from Microsoft Store See how it works
Public Beta v1.0.0

Every feature, completely free for 60 days. Free and paid editions are in planning; details will follow on the Store listing.

Masking and restore — one complete, reversible loop

From batch processing to audited rollback, every step runs locally; every replacement is traceable to its coordinates and reversible to the original text.

Masking workflow

Batch folder selection with recursive scan; multi-file parallel processing (2 threads by default, configurable 1–8).

  • Auto detection: column-keyword + content-sampling dual channel, merged; every result can be overridden in the confirmation dialog
  • Results at a glance: per-file status, elapsed time, replacement count and output path
  • Logs: timestamped entries you can copy, clear and export
  • Ordered output: archived per task timestamp, original folder structure preserved

Mask + fake-data modes

Asterisk masking is the default; fake-data replacement keeps "one original value = one fake value" within a task, so statistics stay consistent.

  • Custom masking template: # keeps the original character in place; other characters are output as-is
  • Custom column rules: configure masking for any column you choose
Template ###****#### → 13812345678 → 138****5678

Two restore channels

"Restore from mapping file" and "Restore from task history" work side by side.

  • Position-level mapping: originals are written back by coordinates — file / sheet / row / column (paragraph and text-block positions in Word) — unaffected by masked-value collisions
  • Pre-restore check: the processed file's hash is verified; if the file was altered manually, that file's restore is aborted with a warning
  • Audit switch: on by default; tasks processed with auditing off keep no mapping and cannot be restored (clearly indicated in the app)

Rule management

Rules persist in a local SQLite database; add, edit, delete and toggle them in the UI.

  • 7 built-in sensitive-field types, enabled out of the box
  • Built-in rules allow parameter changes but cannot be deleted
  • Mapping export: export the mapping workbook (xlsx) for restore and audit

7 built-in sensitive-field types

Checked and ready by default; combine them with custom column rules to cover your business-specific fields.

Company names Person names Mobile numbers Account numbers Unified social credit codes Bank accounts ID card numbers

5 formats, kept as close to the original as possible

Excel keeps formats and styles; Word covers body text, tables, headers/footers and text boxes; CSV keeps its original encoding.

xlsxFormats and styles fully preserved
xlsFormat-safe via local Excel; falls back to reading only and outputs xlsx without Excel
csvEncoding auto-detected (UTF-8 / GBK / UTF-8-BOM), preserved on output
docProcessed via a local Word conversion, output as docx
docxBody text, tables, headers/footers and text boxes

* Formula cells are skipped; only literal values are processed.

Privacy pledge: all local, zero telemetry

Every PrivaMask operation runs on your own computer: no network requests, no telemetry, no analytics, no accounts, no cookies. Source files are read-only; results go to the output folder you choose. See the Privacy Policy.