Unlock PDF Files — Remove Password Protection Remove PDF password.

The tool works under the hood by using the `pdf-lib` library to load and process PDF files. When a user uploads a PDF file, it first attempts to load the file without a password using `PDFDocument.load()`. If this fails, it catches the error and sets the status to 'needs-password', indicating that a user password is required. The tool then uses the `arrayBuffer()` method to convert the uploaded file into an array buffer, which is used to load the PDF document.

The `verifyPassword` function is called when the user enters a password, and it attempts to load the PDF document again using the provided password. If the password is correct, it sets the status to 'ready' and allows the user to proceed with unlocking the PDF. The tool uses memoization through `useCallback()` to prevent unnecessary re-renders and optimize performance.

When the user initiates the unlock process, the tool creates a new `PDFDocument` instance using `PDFDocument.create()` and copies all pages from the original document into the new one using `doc.copyPages()`. This effectively strips the encryption and restrictions from the PDF. The tool also uses the `setTitle()`, `setAuthor()`, and `setSubject()` methods to preserve the original metadata.

The resulting unlocked PDF is saved as a blob using `doc.save()`, and its URL is generated using `URL.createObjectURL()`. The user can then download the unlocked PDF by clicking on the download link, which uses the `Clipboard API` to create an anchor element and simulate a click event. Throughout this process, the tool maintains a responsive UI and updates the user interface accordingly based on the current status.

The use of React's `useState()` hook allows the tool to manage its state effectively, keeping track of variables such as the uploaded file, page count, password, and error messages. This enables it to respond dynamically to user interactions and provide feedback during the unlock process. By utilizing these technologies and techniques, the tool provides a seamless and efficient experience for users looking to remove passwords and restrictions from their PDF files.