Table of Contents

👉 Try the demo: https://github.com/LM-Kit/lm-kit-net-samples/tree/main/console_net/document-intelligence/pdf-toolkit/encrypted_pdf_workflows

Encrypted PDF Workflows for C# .NET Applications


🎯 Purpose of the Demo

An interactive console app showing that every method in the LM-Kit.NET PDF toolkit accepts a password. Inspect, render, search, split, or edit a password-protected PDF, all without ever exporting an unlocked copy to disk.

All processing runs on-device.


👥 Industry Target Audience

  • Legal: signed contracts, NDAs, confidentiality-marked exhibits.
  • Finance: statements, KYC packets, signed disclosures.
  • Healthcare: patient records under HIPAA, lab reports.
  • HR: background checks, signed offer letters.
  • Any team ingesting password-protected PDFs into AI or document-processing pipelines.

🚀 Problem Solved

Most PDF toolkits force you to "unlock" a file first, write an unencrypted copy to disk, and then process it. That breaks audit trails and exposes plaintext on the filesystem. The LM-Kit.NET toolkit threads a password parameter through every entry point, so the encrypted file never leaves its protected state. The demo wraps every supported call (PdfInfo, PdfRenderer, PdfSearch, PdfSplitter, PdfEditor) behind menu picks.


💻 Application Overview

Interactive menu (no command-line arguments) with six modes:

Mode What it does
Inspect PdfInfo.GetPageCountAsync + GetMetadataAsync + GetSecurityHandlerRevisionAsync with password.
Render PdfRenderer.SavePageAsPngAsync using PdfRenderOptions.Password.
Search PdfSearch.FindTextAsync with password, prompts for a query.
Extract PdfSplitter.ExtractPagesAsync with password, prompts for a page range.
Edit PdfEditor.ApplyToFileAsync keeping every-other page via a password-aware Attachment.
All Run all five end-to-end into a chosen output directory.
Quit Exit.

Every mode asks for the encrypted PDF path and password up-front, then routes through the matching SDK call. Ctrl-C cancels cleanly.

✨ Key Features

  • Password threading: every API entry point accepts a password argument; nothing is unlocked on disk.
  • Attachment(path, name, password): one-line pattern shared by every class that consumes an Attachment.
  • PdfRenderOptions.Password: applied to every render method (PNG, JPEG, multi-page TIFF, ...).
  • Async + CancellationToken throughout.

🧠 Model

  • None. This demo is pure document plumbing and does not load an LLM.

🛠️ Getting Started

📋 Prerequisites

  • .NET 8.0 or later
  • A password-protected PDF (Adobe Acrobat, Foxit, or an online tool can encrypt a normal PDF for you).

▶️ Running the Application

git clone https://github.com/LM-Kit/lm-kit-net-samples
cd lm-kit-net-samples/console_net/document-intelligence/pdf-toolkit/encrypted_pdf_workflows
dotnet run

Pick a mode from the menu and follow the prompts.

📚 Related Content

Share