Password protect PDF

Set a password and pick what readers are allowed to do

Developer API

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Protect PDF document online is a utility that allows you to protect your PDF document with a password. Protection is performed using a strong encryption algorithm AES-128 and a password that you specify in the password field. The AES algorithm has been approved by the US National Security Agency as suitable for encrypting highly sensitive information. We do not store your passwords, and documents are deleted from our servers automatically after 24 hours. The encrypted document can be transmitted securely to your colleagues via email or other cloud services. We do not recommend sending your PDF protected documents via email along with a decryption password. This increases the risks that your letter can be intercepted by someone and the attached document, along with the password, will fall into the hands of cybercriminals.
This password protection tool works with all popular formats such as PDF, Word, Excel, PowerPoint and works on any Windows, macOS, Linux or Android operating system. Your protected files are stored on our servers for a limited time and no one has access to them without a special encrypted link. You can also use the "Delete immediately" function and your files will be deleted instantly.
You can also, using our service, send a link to download your protected document to yourself or your partners by email. But keep in mind that only a link to download the document will be sent to the email without specifying the password that you specified for protection.

Lock a PDF using the Password Protect Cloud API.

Protect your PDF file with a password
Once protected, the PDF document can be opened only with the password
To protect the PDF file, we use the crypto algorithm AES 128
In an encrypted PDF document, after entering the password, all restrictions are removed

How to protect PDF file

Open the free Lock PDF app in your browser.
Click inside the file drop area to upload your PDF file or drag and drop it.
Once the file is uploaded, enter a password in the input field to protect your PDF file.
Click the 'PROTECT' button. A download link for the password-protected PDF file will be shown.
You can also send a link to the PDF file to your email address.
Note that the files will be deleted from our servers after 24 hours and the download links will stop working.

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