VeryPDF DRM Protector

This technical document consolidates our full discussion with customers regarding compatibility, security features, encryption strength, mobile behavior, and subscription policy of VeryPDF DRM Protector and Secure Web Viewer. It serves as an official reference for authors, publishers, and organizations seeking a reliable and device-friendly DRM solution for distributing protected e-books and confidential documents.

1. Compatibility Across Windows 7 → Windows 14, macOS, Android, iOS, and Linux

VeryPDF Secure Web Viewer is engineered to work reliably across a wide range of systems — from older computers running Windows 7 and Firefox ESR 115 to the newest versions of Windows, macOS, Android, and iOS.
This ensures that all your readers, regardless of their device age or browser version, can access your protected e-book smoothly and securely.

✔ Recommended Viewer for Maximum Compatibility

For users who require maximum stability — especially those using older operating systems or older browsers — we provide a specially optimized version of the Secure Web Viewer.

Most Compatible Viewer Version:
https://online.verypdf.com/app/reader2/web/index.php

This version has been fully tested and validated to work on both modern and legacy platforms. It offers the broadest compatibility while still maintaining all essential DRM protections.

Supported Systems and Browsers

✔ Windows (Full Range Support)

This viewer supports all common Windows environments, including:

• Windows XP
• Windows 7
• Windows 8 / 8.1
• Windows 10
• Windows 11
• Windows 14 and newer

Even computers with older CPUs, outdated GPU drivers, or limited graphics acceleration can still use this viewer without encountering rendering issues like black screens.

✔ Browser Compatibility

Special effort has been made to maintain compatibility with older browsers often used on legacy systems:

• Firefox 115 ESR (Extended Support Release)
• Earlier versions of Firefox (down to ESR 52 in many cases)
• Chrome 49 and newer
• Legacy Chromium-based browsers
• Older WebView-based Android browsers

This ensures that readers using older devices — including those who cannot update their browsers — can still open and read your protected documents.

✔ Cross-Platform Support (Desktop & Mobile)

Aside from Windows, the viewer also works on:

• macOS (Intel & Apple Silicon)
• Android phones and tablets
• iOS/iPadOS devices
• Linux desktops and browsers
• ChromeOS

No installation or plugin is required — everything runs inside the browser through a secure rendering layer.

✔ Works on Older Hardware

The compatible version is optimized for:

• Low-performance CPUs
• Limited GPU acceleration (or no GPU acceleration)
• Older graphics drivers
• Legacy systems with outdated WebGL implementations

This dramatically reduces the chance of issues like black screens, slow rendering, or viewer crashes.

2. Encryption Technology: AES-256 Military-Grade Protection

VeryPDF DRM Protector is designed to ensure that every protected PDF receives the highest level of encryption available today. Even if the web interface may display a “128-bit” label during selection (for compatibility purposes), the actual encryption performed by our DRM engine is ALWAYS AES-256.

This means every PDF is protected with military-grade, industry-approved cryptography, regardless of the settings chosen by the end user.

Core Encryption and Security Architecture

✔ AES-256 Encryption (Advanced Encryption Standard)

• AES-256 is the strongest practical encryption standard globally.
• It is approved for securing classified military and government documents.
• No known attacks can decrypt AES-256 without the key — even with supercomputers, the brute-force time is estimated in trillions of years.

✔ Server-Side Key Management

• Encryption keys are generated, stored, and managed only on our server.
• Keys are never transmitted to the reader in raw form.
• Users cannot extract, guess, or reconstruct the encryption key.
• Even device-level forensics cannot retrieve the keys.

✔ Dynamically Generated Session Keys

• Each reading session uses a temporary session key, generated uniquely for each user and device.
• These keys automatically expire and cannot be reused.
• This prevents replay attacks, local caching, or unauthorized reuse of a viewing session.

✔ Zero-Exposure Architecture

• The protected PDF is never decrypted on the user’s device.
• The decryption process happens in a secure, controlled server environment.
• Only rendered image streams or secured canvas data are sent to the viewer.
• No plaintext content, no unencrypted PDF data, and no reusable key ever reaches the local device.

✔ Controlled Rendering Environment

• The content delivered to the viewer is rendered on demand.
• Content is never stored as a PDF, never cached, and never saved locally.
• Browser cache, temporary files, and memory buffers are tightly controlled or overwritten.
• This prevents:
  • Local file extraction
  • Offline saving
  • Reverse engineering
  • Decryption via local caching

Why AES-256 Is Critical for Authors and Publishers

AES-256 remains the most secure algorithm available for document protection. It provides:

• Military-grade security — approved for the most sensitive classified documents.
• Future-proof protection — resistant to current and foreseeable cryptographic attacks.
• High trust — used by governments, financial institutions, and major enterprises worldwide.
• Strength against piracy — ensures your e-book or PDF cannot be extracted, copied, or decrypted.

VeryPDF combines AES-256 with strict server-side control to deliver a level of PDF protection far stronger than standard PDF passwords or generic DRM tools.

3. Why Customers See Sample PDF When Uploading from Mobile

Some users may upload from Android/iOS and still see the default sample PDF.
This is caused by:

• Browser caching
• Form autofill
• Old cached service workers
• Local storage not refreshed

Fix:

• Clear browser cache
• Use Incognito mode
• Or upload directly via:

https://drm.verypdf.com/online/

We will enhance mobile upload logic to eliminate this issue in future versions.

4. PDF Protection Features Supported in Secure Web Viewer

The user’s requested features are fully supported:

Important note on mobile screenshots

On Android/iOS, no Web Application can fully block screenshots due to OS restrictions, but dynamic watermarks and device-limit policies provide strong deterrence.

Dedicated native apps can block screenshots, but that requires separate development for each OS.

5. Why We Differentiate Real vs. Virtual Printers

In the DRM industry, different customers have different requirements for printing control. To meet professional and enterprise-level workflows, VeryPDF’s DRM engine must distinguish between real (physical) printers and virtual printers.

Why This Distinction Is Necessary

Many enterprise clients use printing as part of their business workflow and require fine-grained control:

✔ Some customers allow printing only to real, physical printers
These clients use DRM to block unauthorized duplication but still need to print controlled physical copies for auditing or compliance.

✔ Some customers charge per print job or per printed page
For example, print-on-demand businesses or document services track usage using physical printers only.

✔ All DRM systems must block virtual printers
Virtual printers (like PDFCreator, Microsoft Print to PDF, Foxit PDF Printer, XPS Document Writer, etc.) can create new, clean PDF files.
This would completely bypass DRM.
Therefore, virtual printers must be blocked at a system level.

Because of these industry requirements, our DRM engine includes printer detection logic that can differentiate between physical and virtual printers.

How This Applies to Your Use Case (Secure Web Viewer)

For your e-book, this distinction is not necessary — because:

Printing is 100% disabled in Secure Web Viewer

No matter what printer is installed on the device:

• ✔ Real printer → Blocked
• ✔ Virtual printer → Blocked

The viewer provides zero printing capability, so readers cannot output even a single page in any form.

This ensures maximum protection for your digital book without requiring any special configuration.

6. What Happens If Subscription Expires?

If a subscription expires:

• Reader access to protected e-books is blocked
• Security policies must remain active
• We send email reminders before expiration

Authors can avoid interruption simply by renewing on time.

7. Protection of the Author’s Original PDF — No File Exposure

Ensuring the security of an author’s original PDF is a top priority at VeryPDF. Our system is designed so that at no point is your unprotected file exposed, either to our staff or to any external parties. Below are the key security measures we implement:

1. No Unprotected Files Stored

• The original PDF that you upload is never stored in its unencrypted form on our servers.
• Immediately after the encryption process is complete, the original file is automatically and permanently deleted.
• This ensures that even in the unlikely event of a server compromise, your original, unprotected content cannot be accessed.

2. Only Encrypted Versions Are Stored

• After encryption, only the DRM-protected version of your PDF is retained.
• This version includes all the protection features you configure, such as device limits, dynamic watermarking, and anti-copy/anti-print restrictions.
• All operations, including viewing and access control, are performed exclusively on this encrypted version.

3. Internal Staff Cannot Access Original Files

• Our engineers and staff do not have access to your original, unprotected PDF.
• Technical safeguards and internal policies make it impossible for anyone within VeryPDF to view, copy, or retrieve the unencrypted content.
• This guarantees that your intellectual property remains fully under your control at all times.

4. Written Agreement for Maximum Assurance

• Upon request, VeryPDF can prepare a formal agreement confirming that:
  • Your original file remains fully protected
  • The file cannot be processed, copied, or modified by any unauthorized third parties
  • The protection remains effective even after the subscription or license expires

By combining these measures, VeryPDF ensures that authors can safely use our DRM system without ever having to worry about exposing their valuable PDF content. The original work is always secure, and the encrypted version delivers robust protection for distribution.

8. Custom Plans — Based on Exact Requirements

Currently, we do not provide extra predefined custom plans.

However, we can design a custom plan if the author:

• Describes required features
• Tells us expected number of readers
• Provides acceptable budget range

After receiving this information, we evaluate feasibility and prepare a tailored offer.

9. Human Support — No “Company AI” Responses

All replies to customers are from real human staff.

We do not use any automated “company AI chatbot” to answer support emails.

If customers need technical explanations involving AI-based information, a human staff member will provide it manually.

10. Summary

VeryPDF Secure Web Viewer + DRM Protector provides:

• Multi-platform compatibility (Windows 7 → latest OS)
• AES-256 military-grade encryption
• Strong anti-copy, anti-print, watermark, device-limit protections
• Screenshot blocking on Windows/macOS systems
• Safe, isolated file processing
• Flexible subscription and potential custom plans
• 100% human support

This technical guide is intended to help authors, publishers, teachers, trainers, and copyright owners understand how to safely distribute protected e-books with maximum compatibility and minimal reader friction.