Protect PDF

The PDF is wrapped inside a password-protected ZIP archive using AES encryption. When the recipient enters the password, the archive opens and reveals the PDF inside. This approach works on every operating system and every PDF reader, because AES-encrypted ZIPs are a universally supported format. It's a stronger and more interoperable method than PDF's own native encryption, which has some known weaknesses depending on the reader.

Through a different channel than the file. Send the protected file by email, send the password by SMS or a phone call or a chat message on a different app. The point is that if an attacker compromises one channel, they don't automatically have access to the other. Never write the password in the same email as the attachment.

Length over complexity for most uses. A phrase like "Mango-River-2026-Audit" is harder to crack than a short string of symbols like "#a!K9w&". Twelve characters or more with mixed words and numbers is a sensible target. Avoid passwords you've used elsewhere; if any one of your accounts is breached, the reused password becomes a master key.

Yes. Once they have the password, the file is in their hands and they can do whatever they like with it. Password protection prevents unauthorised reading; it doesn't prevent unauthorised forwarding by people who already have access. For documents where you need to prevent forwarding, you'd want a more sophisticated digital rights management system.

Yes, when paired with a strong password and shared through a separate channel. AES encryption with a 12+ character password is computationally infeasible to crack in any reasonable time. The weak link in this kind of setup is almost always the password (too short, reused, or written down where it shouldn't be), not the encryption itself.

It applies standard 128-bit PDF encryption — the scheme every PDF reader supports — and writes an encryption dictionary into the file, so content streams, fonts and images are all scrambled. That is far stronger than the old 40-bit scheme some tools still use, and any standards-compliant reader will ask for the password before showing a page. For real-world safety, the length of your password matters most: use a passphrase of 12 characters or more.

Yes. The password travels inside the file, so when you open the protected PDF in your phone's PDF viewer, Google Drive, or a WhatsApp preview on Android or iPhone, it will ask for the password before showing any page. Share the password separately by call or SMS.

This tool sets an open password, which is required just to view the document. Once someone enters the correct password, they can read it normally. If you only want to block copying or printing while leaving the file openable, that is a different permissions-based restriction.

No. The password is used to derive the encryption key and is never stored on our server, so there is no way to recover or reset it after encryption. Keep a copy of the passphrase somewhere safe before you send the file, or re-create the PDF from the original and encrypt it again.

The file is processed on our server to generate the encrypted copy and is not retained afterward. For maximum caution with Aadhaar, you can also mask the number first, then protect the PDF, and always send the password over a channel separate from the email carrying the file.

Yes — once you know the password, you can strip it back off with the Unlock PDF tool to produce a normal, openable copy. Keep the protected version for sharing and an unlocked version for your own records if you like.