Processed entirely on your device — nothing is uploaded
How to use the protect pdf
- 1Drop the PDF you want to protect into the box above.
- 2Choose a password and type it twice.
- 3Tick the permissions you want to allow.
- 4Press Add password and download the encrypted file.
Why doing this locally actually matters
With most tools on this site, local processing is a nice privacy property. Here it is the whole point. Uploading a confidential document *and* the password that protects it to a third-party server, in the same request, defeats the purpose of encrypting it — you have handed over both the lock and the key.
This tool never transmits either. The document is read into memory, encrypted by code running in your browser, and written back out as a download. You can verify that by opening your browser's network panel while you use it, or by disconnecting from the network after the page loads.
It also means we cannot help you if you forget the password, which is a genuine limitation rather than a policy choice. There is no copy anywhere for us to recover.
Two kinds of password, and what each one does
PDF supports two passwords. The user password (sometimes called the open password) is required to view the document at all — without it, the file is unreadable ciphertext. The owner password controls permissions: what a viewer may do once the file is open.
This tool sets both. The password you type becomes the user password, and a derived owner password is set alongside it so that the permissions you choose cannot simply be lifted by re-saving the file.
The permissions themselves — print, copy, edit — are honoured by well-behaved PDF readers, but they are advisory rather than cryptographic. The content is decrypted once the file is open, so a determined user with the right software can bypass a permissions restriction. Do not rely on "copying disabled" to protect text you genuinely cannot allow to circulate; rely on the open password to control who sees the document at all.
Choosing a password that is worth having
PDF encryption derives its key from your password, so the password is the security. A four-character password on a 256-bit cipher gives you four characters of protection, because an attacker attacks the password rather than the cipher.
A long passphrase of unrelated words is both stronger and easier to remember than a short string of substituted characters. Four random words comfortably beats eight characters of the P@ssw0rd variety, and you can actually dictate it over the phone.
Send the password separately from the document, and by a different channel. Emailing an encrypted attachment and its password in the same message is a surprisingly common habit that provides no protection at all — anyone who intercepts one has intercepted both.
What encryption does not do
It does not stop someone who can open the file from screenshotting it, printing it if printing is allowed, or retyping it. Encryption controls access, not what an authorised reader does afterwards.
It does not hide the fact that a document exists, nor its filename, size or metadata in some contexts. If the existence of the document is itself sensitive, encryption of the contents is not sufficient.
And it is not a substitute for redaction. If a page contains information a recipient must not see, remove that information from the document rather than relying on them not being able to copy it.
Frequently asked questions
Can you recover my password if I forget it?
No. The password never leaves your device and no copy exists anywhere. A forgotten password means the document cannot be opened. Write it down before you download the file.
Is my document uploaded to encrypt it?
No. Both the file and the password stay in your browser. Uploading them would defeat the purpose.
What is the difference between the user and owner password?
The user password is needed to open the document. The owner password controls permissions such as printing and copying once it is open.
Can permissions be bypassed?
Yes, by software that ignores them — permissions are advisory once the file is decrypted. The open password is the part that provides real protection.
How strong should my password be?
Long rather than complicated. Four random words beats eight substituted characters, and is far easier to remember and to communicate.
Will the encrypted file open on a phone?
Yes. Standard PDF encryption is supported by every mainstream reader on every platform.