PDF Password - Lock or Unlock PDFs (AES-128) Free

Switch to the Lock tab, drop a PDF, enter a password (and confirm it), and click Lock PDF. The output is an AES-128 encrypted PDF that requires the password to open in any PDF viewer. Distribute the locked file freely and share the password through a separate channel.

AES-128 is the same encryption strength banks use for online banking. With a strong password (12+ characters mixing letters, numbers and symbols) the file is mathematically unbreakable in any reasonable timeframe. Weak passwords can be brute-forced — use a passphrase or a password manager-generated string.

Yes — switch to the Unlock tab, drop the locked PDF, enter the password you already know, and click Unlock PDF. The output is the same PDF without encryption. This tool does NOT crack unknown passwords; it requires the correct password to decrypt.

The tool reports "Wrong password" and refuses to produce output. There is no brute-force, no retry penalty, no logging of attempts. If you don't know the password, contact the document originator — there is no legitimate way to bypass strong PDF encryption.

Yes — the password is sent over HTTPS to perform the encryption/decryption server-side, then immediately discarded. We never log passwords or retain encrypted output. For ultra-sensitive workflows where even transient transit is unacceptable, use a desktop tool like qpdf or pikepdf locally.

Yes — AES-128 PDF encryption is supported by every major PDF viewer: Adobe Acrobat, Apple Preview, Chrome's built-in viewer, Foxit, Edge's PDF viewer, and mobile readers on iOS and Android.

Currently the tool uses a single user password (open-the-file password). Advanced PDF security separates the user password (open) from the owner password (allow/restrict printing, copying, editing) — that workflow needs a desktop tool. For most use cases, the user password is what people mean by "password-protect this PDF".

Free, no signup. Files up to 50MB. No watermark added during lock/unlock. Use it commercially for contracts, NDAs, tax returns and any other document that needs to be sent over email without snoopers reading it.

Open the Lock tab, drop your PDF, enter and confirm a password, then click Lock PDF. The file is encrypted with AES-128 so it cannot be opened without that password in any PDF viewer. Share the locked file freely and send the password through a separate channel. To remove protection from a file you own, use the Unlock tab with the correct password.

Yes — click the eye icon inside the password field to toggle between masked and plain text. This is useful for confirming a long, randomly generated password was typed correctly, since a typo in the field means you could lock yourself out of your own file.

The confirm-password field catches typos before they get baked into the encrypted file — if the two fields don't match, the tool blocks the lock and shows "Passwords do not match" instead of producing a PDF you can never open again. Unlock mode only asks once because you're supplying a password that already exists.

Type the password once, retype it in Confirm password, then click the eye icon to reveal both fields and visually check they're identical before clicking Lock PDF. Since AES-128 encryption has no recovery backdoor, this quick check with all three controls is the only safety net if you mistype a long, complex password.