Privacy Mask

Privacy Mask

Detect and mask sensitive information in images locally before they leave your machine.

Prerequisites

This skill requires the privacy-mask CLI to be pre-installed on the system. If it is not available, inform the user that they need to install it first:

1. Install via pip: pip install privacy-mask
2. Ensure Tesseract OCR is installed: brew install tesseract (macOS) or apt install tesseract-ocr (Linux)
3. Set up the Claude Code hook: privacy-mask install
4. Verify: privacy-mask --version

After install, all images are automatically masked before upload. No further action needed.

When to use

• User sends a screenshot or image file (.png, .jpg, .jpeg, .bmp, .tiff) that may contain private data
• User mentions privacy, masking, 脱敏, or 打码
• You need to analyze an image but want to redact sensitive info first
• IF the user shares a screenshot for debugging, THEN run privacy-mask mask <path> --dry-run first to check for PII

Manual usage

Mask an image:

privacy-mask mask /path/to/screenshot.png
privacy-mask mask /path/to/screenshot.png --in-place
privacy-mask mask /path/to/screenshot.png --dry-run   # detect only
privacy-mask mask /path/to/screenshot.png --detection-engine regex  # regex only, skip NER

Output is JSON:

{
  "status": "success",
  "detections": [{"label": "PHONE_CN", "text": "***", "bbox": [10, 20, 100, 30]}],
  "summary": "Masked 1 regions: 1 PHONE_CN"
}

What it detects

• IDs: Chinese ID card, passport, HK/TW ID, US SSN, UK NINO, Canadian SIN, Indian Aadhaar/PAN, Korean RRN, Singapore NRIC, Malaysian IC
• Phone: Chinese mobile/landline, US phone, international (+prefix)
• Financial: Bank card, Amex, IBAN, SWIFT/BIC
• Developer keys: AWS, GitHub, Slack, Google, Stripe tokens, JWT, connection strings, API keys, SSH/PEM keys
• Crypto: Bitcoin, Ethereum wallet addresses
• Other: Email, birthday, IP/IPv6, MAC, UUID, license plate, MRZ, URL auth tokens
• NER (optional): Person names, street addresses, organizations, dates of birth, medical conditions

Constraints

• Do NOT send unmasked images to any external API or cloud service
• Do NOT skip masking when detections are found
• Do NOT modify the original image unless --in-place is explicitly requested

Important

• All processing is local and offline — no data leaves the machine
• The hook intercepts images before upload to cloud API
• Configure rules in the bundled config.json or pass --config for custom rules