PDFs can carry sensitive information — contracts, statements, medical records — so controlling who can open them matters. slimdocs offers two complementary tools: Protect PDF to add a password, and Unlock PDF to remove one you already know. Here's how each works and when to use it.
Protecting a PDF (adding a password)
Protecting a PDF encrypts it so that it can only be opened by someone who knows the password. slimdocs uses 256-bit AES encryption — the same strong standard used across the security industry. Once protected, the file's contents are scrambled on disk; without the password, they're unreadable.
This is the right choice before emailing something confidential, storing a document in shared cloud storage, or handing a file to someone over an untrusted channel.
- Open slimdocs and choose Protect PDF.
- Drop in the PDF and enter a strong password.
- Download the encrypted copy. Share the password through a separate channel — never in the same email as the file.
Unlocking a PDF (removing a password)
If you have a PDF that asks for a password every time you open it — and you know that password — you can remove it so the file opens freely going forward. This is convenient for documents you reference often and have legitimate access to, like your own bank statements.
Importantly, this is not a way to break into a file you don't have the password for. slimdocs requires you to enter the correct current password; it simply uses it to decrypt the file and save an unprotected copy. It is not, and cannot be used as, a password-cracking tool.
- Choose Unlock PDF.
- Drop in the file and enter its current password.
- Download the unlocked copy.
What about Word and Excel files?
slimdocs can also remove passwords from Office documents (Word, Excel, PowerPoint) you can already open, using the Unlock Office tool. As with PDFs, you must supply the correct current password — it decrypts a file you have access to, nothing more.
Choosing a strong password
- Use a long passphrase — length beats complexity.
- Don't reuse a password you use elsewhere.
- Send the password separately from the file.
Every operation happens in memory and the files are discarded immediately after your download — your documents and passwords are never stored.