first version

README.md

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+# SANS Courseware Watermark Remover
+
+Removes personalized SANS “Licensed To …” watermarks (names, emails, hashes, dates) by deleting the actual `BT…ET` text objects in the PDF—no white boxes, no selection artefacts.
+
+## Quickstart
+
+1. **(If encrypted) Decrypt first with `qpdf`:**
+   
+   ```bash
+   qpdf --password='<YOUR_PASSWORD>' --decrypt INPUT.pdf INPUT_unlocked.pdf
+   ```
+
+2. **Install dependencies (Python 3.9+):**
+
+   ```bash
+   python -m venv .venv
+   source .venv/bin/activate            # Windows: .venv\Scripts\activate
+   pip install -r requirements.txt
+   ```
+
+3. **Run the sanitizer (auto-creates `<input>_clean.pdf`):**
+4. 
+   ```bash
+   # Recommended latest script:
+   python enhanced_sanitize_pdf.py INPUT_unlocked.pdf
+   ```
+
+## Notes
+
+* The tool targets common SANS watermark patterns:
+  * Invisible 36-pt text with rendering modes 1/3,
+  * Rotated diagonal overlay using −25-pt fonts,
+  * Footer lines at 10/18-pt.
+* If your course PDFs use different fonts/sizes, adjust the regex patterns inside the script.
+