How to password-protect a PDF (and remove the password later)

Email is like a postcard: on its way to the recipient it passes through several servers, and once sent it stays in someone else's inbox forever. That is why documents with sensitive data – payslips, contracts, copies of ID documents, medical results, price offers – are worth locking with a password before sending. If the message reaches the wrong person, or someone breaks into an account, the document stays unreadable without the password.

How to lock a PDF with a password

1. Open Protect PDF and select the document.
2. Enter the password twice. The "Show password" option helps you check for typos.
3. Optionally prevent editing and copying of text.
4. Click "Protect PDF" and download the encrypted document.

The document is encrypted with AES-256, the strongest protection PDF supports. It opens in all common programs – Adobe Reader, Chrome, Edge, phone readers – but only after the password is entered.

What makes a good password

Encryption is only as strong as the password. "1234" or a date of birth can be guessed in seconds, AES-256 or not.

• At least 10–12 characters. Length matters more than complicated symbols.
• A phrase of several words is easy to remember and hard to guess: for example four random words with a number in between.
• Avoid the obvious: names, ID numbers, birth dates, the company name, "password".
• Don't reuse the password you use for email or banking.

How to send the password

The most common mistake: document and password in the same email. Whoever gets the email gets both. The rule is simple – send the password through a different channel:

• the document by email, the password by text message or a messaging app;
• or tell the password over the phone;
• with regular partners, agree on one password in advance, in person.

Preventing copying and editing

An extra option sets restrictions: a recipient who opens the document with the password can read and print it but cannot change the content or copy the text. Useful for offers, price lists and contracts. Standard PDF programs respect these restrictions, but specialised tools can bypass them – the real protection is the open password.

How to remove the password later

Banks, operators and employers often send statements and payslips locked with a password. When you want to archive such a document or forward it to your accountant without typing the password every time:

1. Open Unlock PDF and select the document.
2. Enter the password used to open it.
3. Download the version without protection.

The tool works only if you know the password – it does not crack or guess unknown passwords. It is meant for your own documents.

Is it safe to give the password to the tool?

Encryption runs on our server using the proven open-source program qpdf. The file and password are sent over an encrypted HTTPS connection, used only for processing and deleted immediately afterwards. The password is never written to any log.

Extra protection: a watermark

When you send a copy of an ID card or diploma, a password protects the document in transit but not against misuse by the recipient. Add text stating the purpose across the copy, for example "Only for opening an account at XY Bank", with Watermark.

In short

Lock a sensitive PDF with a long password, send the password through a different channel and keep it somewhere safe. The document then stays unreadable even if the email ends up in the wrong hands.