How to Lock a PDF from opening
You can use either passwords or certificates to lock a PDF file from opening but they both have their problems.
A more secure and easier way to prevent a PDF being opened by unauthorized users is to use encryption with licensing controls and transparent key management. You therefore do not have to worry about key distribution. This is what Locklizard uses along with device locking to prevent encryption keys (and therefore your documents) from being shared.
How to Lock a PDF from editing
Most PDF editors enable you to lock a PDF from editing. However these restrictions can be easily removed.
Locklizard automatically prevents PDF editing when you protect it. Users cannot edit content or copy/paste it to other applications. You can also lock PDF forms so that form fields cannot be edited and modified in any way, but the user can still enter text in the fields provided.
Locking PDFs with Adobe Acrobat
Adobe Acrobat lets you lock or encrypt PDF files with a password so that they are set to view or read only (cannot be edited or printed).
However, the only protection available is the password which can be easily removed using freely available PDF password removal tools. Once the password is removed the recipient can do what they like with the file.
How to lock PDF from editing with a password:
- Open your PDF in Acrobat and press the “Protect” button in the sidebar.
- Click “Protect Using Password” in the top bar.
- Select “Editing” and enter a secure password.
- Save your password protected document.
You can then apply a document open password (Viewing) in the “Advanced options” section of the security header, but that does not prevent users removing the restrictions. Anyone that has the document open password (any user you share the PDF file with needs it) can remove the PDF restrictions in seconds.
How to edit a password locked PDF
If a user has protected their PDF with Adobe Acrobat, editing it is easy. This is especially true if they have the open password, which everybody who wants to view the document will need.
Here’s the simple, four-step process.
- Upload the document to an online password remover tool
- Enter the open password
- Wait for the website to strip the permissions password
- Download the modified PDF and edit it in any PDF editing software
If the open password is not immediately available, it does not mean a user cannot edit the PDF. A PDF remover tool can still reveal or remove the open password given enough time. It will also strip any editing controls from the document.
Alternatively, users can convert from PDF to another format by opening it in Google Docs or Microsoft Word and editing it that way.
How to print a PDF that is locked with a password
The method to print a password-locked PDF is the same as above. Users upload the protected document to an online service, download the unprotected version and hit “print”, or crack it with a PDF password remover tool.
If the document has any watermarks, they can of course edit the document to delete those before printing it.
So the Adobe method of locking PDFs to prevent changes provides zero protection since it can be easily defeated. Printing a locked PDF is incredibly easy and so is removing any editing restrictions.
Locking PDF files online
There are many PDF tools similar to Adobe that let you protect a PDF online. The problem however is that you have to upload your unprotected PDF files to a cloud server where they could be compromised. This might be OK for non-sensitive or non-confidential PDF documents, but most businesses do not want to expose their documents to a third party, which is why they are protecting them to begin with.
So, while online PDF locking tools may seem attractive, they are actually less secure and provide only simple password protection which is easily removed.