How to Zip and Password-Protect a PDF File for Secure Sharing

When you send contracts, reports, or ID scans by email, you do not want anyone else opening them. That is where password-protected PDFs and password-protected zipped folders come in.

In this guide, we focus on protecting PDFs first, then show you how to compress and bundle them into a password-protected zipped folder on Windows, Mac, and Linux.

You will see when to use PDF encryption, when a zipped folder makes sense, and how Smallpdf helps you keep everything secure.

Use this as your fast reference before you get into the steps.

Use a password-protected PDF when you:

• Share one document (contract, invoice, report)

• Need open/edit/print permissions on that single file

• Want strong AES encryption directly on the PDF

Use a password-protected zipped folder when you:

• Share many PDFs or mixed files together

• Want one attachment instead of several

• Already protected each PDF, and now want a secure bundle

You can safely combine both: encrypt each PDF, then add them to a password-protected zipped folder for an extra layer and easier sharing.

Only people who know the password can open the document.

Why use Smallpdf for PDF security?

• Browser-based: Works on Mac, Windows, Linux, and mobile.

• Strong encryption: PDFs are secured with industry-standard AES encryption.

• Automatic deletion: Files are automatically removed from our servers after one hour of processing.

• Free option: You can protect individual PDFs without creating an account.

Even though the file compresses when you zip it, there is a better way to shrink your file.

Encrypted PDFs that contain scans, images, or multi-page reports can still be quite large, which makes email sending or uploads harder.

Compress PDF gives you a smaller, share-ready file without changing the password or weakening encryption.

Here’s how  to compress a file with Smallpdf:

1. Go to Compress PDF on Smallpdf.

2. Click “Choose File” (or use the drag-and-drop area below) to upload your already-protected PDF.

3. Pick a compression level that fits your needs (standard for everyday sharing, stronger compression for very large files).

4. Click “Compress” and wait for processing to finish.

5. Download the optimized, still password-protected PDF to your device.

You can then:

• Send the compressed, protected PDF directly, or

• Add it to a password-protected zipped folder together with other files.

Compression reduces file size, not security. Your password and encryption still protect the document after compression.

Once your PDFs are protected and compressed, you might want to group several documents into a single password-protected zipped folder. The exact steps depend on your operating system.

1. Create a Password-Protected Zipped Folder on Windows

Windows File Explorer can zip folders, but it cannot add a password. For a password-protected zipped folder, you need a compression app that supports encrypted ZIPs (many free tools do).

Typical flow with a ZIP app that supports encryption:

1. Install a ZIP tool with password support (for example, a free archiver).

2. Right-click the folder or files you want to protect.

3. Choose “Add to archive…” or the equivalent option.

4. Select “ZIP” as the archive format.

5. Enable password protection and choose “AES encryption” if available.

6. Enter and confirm a strong password, then click “OK” or “Create.”

You now have a password-protected zipped folder that recipients must unlock with the password.

2. Create a Password-Protected Zipped Folder on Mac (Terminal)

Finder can create ZIPs, but it does not add passwords. To encrypt a ZIP on Mac, use the built-in “zip” command in Terminal.

1. Put all the files you want to protect into one folder.

2. Open “Terminal.”

3. Run this command, replacing names with your own: zip -er secure-folder.zip /path/to/your/folder

4. Enter and confirm your “ZIP password” when prompted.

This creates secure-folder.zip as an encrypted ZIP. Anyone who opens it will be asked for the password.

3. Create a Password-Protected Zipped Folder on Linux

Most Linux systems include the zip command with encryption support.

1. Open your terminal.

2. Navigate to the folder with your files.

3. Use: “zip -er secure-folder.zip your-folder-or-file.”

4. Set and confirm the password.

Your encrypted ZIP is now ready to share.

Both ZIP archives and PDFs can be encrypted, but they behave differently.

PDF encryption (with tools like Smallpdf):

• Uses strong AES encryption on the PDF itself.

• Can distinguish between open password and permissions (print, copy, edit).

• Works well when you protect individual documents.

ZIP encryption (password-protected zipped folders):

• Protects the entire archive, including many files.

• Strength depends on the tool: modern apps support strong AES; older “ZipCrypto” is weak.

• Useful when you send several files as one package.

For the best security:

• Encrypt each PDF first with a strong password.

• Then, if you need to bundle them, create a password-protected zipped folder as a second layer.

A password is only as strong as the way you create and share it.

Create strong passwords

• Aim for 12–16 characters at minimum.

• Mix uppercase, lowercase, numbers, and symbols.

• Avoid names, birthdays, or common words.

• Use a “passphrase” (several random words) to keep it memorable.

Share passwords safely

• Never put the file and password in the same email.

• Send the password over a different channel (chat, SMS, or a call).

• For repeated sharing, store passwords in a password manager instead of notes.

Built-in options like Preview and Word are useful, but they have limits.

Built-in tools (Preview, Word, OS ZIP)

• Convenient if you already work in those apps

• Fine for single, simple documents

• OS ZIP tools often lack password protection from the GUI

• Settings vary across systems, making them harder to standardize in a team

Smallpdf

• Works in any browser, on any device

• Uses strong, modern encryption for PDFs

• Integrates with Google Drive, Dropbox, or OneDrive.

• Supports batch protection and other workflows with Pro

You can combine them: design documents in Word, secure them with Smallpdf, then zip them if you want a single package.

When you protect your PDFs with strong passwords and, when needed, bundle them into password-protected zipped folders, you reduce the risk of sensitive files landing in the wrong hands.

Smallpdf gives you a simple way to encrypt those PDFs in your browser, and then you can decide whether you also want the extra organization and protection of a zipped folder for sharing.