Can I remove a password from a PDF I own?

If it is a permissions password, yes — the document is not encrypted, so the restrictions can be cleared. If it is an open password, you need the password itself; supply it and the file can be decrypted and saved without one.

Why can I copy text from a PDF that says copying is not allowed?

Because the restriction is a flag rather than a lock. Your viewer is not enforcing it. The content was never encrypted, so any software that reads the file can read all of it.

Is a password-protected PDF safe to email?

An open password with a strong passphrase and AES encryption is reasonable protection in transit. It stops mattering the moment you put the password in the same email, which is the mistake almost everyone makes.

difference between pdf passwords

The Two Kinds of PDF Password

PDF supports two different passwords doing two different jobs. One is real encryption. The other is a polite request that most software honours and nothing enforces.

The open password

Also called the user password. Set one and the file's contents are encrypted. Without the password there is nothing to read — the bytes on disk are ciphertext, and no viewer, however permissive, can display the document.

This is real protection, and its strength depends on which encryption the file uses. Old PDFs used 40-bit or 128-bit RC4, which is now weak. Modern ones use AES-128 or AES-256, which is not. In every case the password itself is still the weak point: an AES-256 PDF protected by "invoice2024" is protected by "invoice2024".

If you are sending something confidential, this is the one you want — and the password has to travel by some other channel than the email carrying the file, or you have achieved nothing.

The permissions password

Also called the owner password. The document opens for anyone, with no prompt at all. What the password controls is a set of flags stored inside it: may this be printed, may text be copied, may pages be extracted, may the form be filled.

Those flags are advisory. Nothing about the file prevents any of these actions — the file simply states a preference, and it is up to the viewer whether to respect it. Acrobat and most mainstream readers do. Plenty of other software does not, and any tool that can read the file can ignore the flags entirely, because the content was never encrypted in the first place.

This is why a PDF can refuse to print in one application and print without complaint in another. Nothing is broken. The second application is simply not choosing to enforce someone else's preference.

Open password: Encrypts the content. No password, no document. Genuine protection.
Permissions password: Sets flags for printing, copying, and editing. Honoured by convention, not enforced.
Both at once: Possible and common. The file needs one password to open and a different one to lift the restrictions.

Which one do you have?

If the file asks for a password before it will show you anything, that is an open password. If it opens straight away but printing is greyed out, or copying does nothing, that is a permissions password.

The practical consequence is what you can do about it. Removing permissions restrictions from a document you can already open is straightforward, because nothing was encrypted. Opening an encrypted file without its password is not something any tool can do for you — it would require breaking the encryption, and if that were feasible the encryption would be worthless.

Choosing one

Use an open password when the contents are genuinely confidential and you accept that anyone with the password has full access. Send the password separately — a different channel, ideally a different medium.

Use a permissions password when you want to signal intent: this is the final version, please do not edit it. It is a reasonable thing to want and a reasonable thing to set. Just do not mistake it for security, and do not rely on it for anything that matters legally or commercially.

If your actual goal is that the document cannot easily be altered, flattening it is a better fit than a permissions password. It merges form fields and annotations into the page itself, so there is nothing left to edit rather than a request not to.