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Participating Frequently
June 3, 2021
Question

PLEASE HELP ME: How To Keep .PDF Files From Being Modified?

  • June 3, 2021
  • 4 replies
  • 4822 views

Hello everyone,

 

I'm new here and I really need some help... :'( 

 

I'm finding that I'm using ebooks more and more and these come in the .PDF format. I now have many more ebooks rather than traditional physical books. 

 

This is my big worry:

That the text in ebooks that are in .PDF files I have purchased and are stored on my local hard drives will be modified without my knowledge and that I would be reading .PDF files that have been modified without my knowledge and therefore learning incorrect information. I also have many .PDF files that were free and completely legal as well and I'm worried about these as well! :'(

 

Is there any way I can make it impossible for .PDF files to be modified/unaltered?

 

Any help would be greatly appreciated. :'(

This topic has been closed for replies.

4 replies

jane-e
Community Expert
July 31, 2021

Who do you think is going to modify PDFs on your hard drive? Have you set your computer that no one can login unless the know the password?

 

If you store a copy of the PDFs in another location, then you can go to File > Properties and confirm the modification date before you start reading your text books.

 

~ Jane

Bernd Alheit
Community Expert
July 30, 2021

Sign the document with a certificate.

try67
Community Expert
June 4, 2021

If a file is saved on your computer then only you have access to it, unless your computer has been hacked, in which case you have bigger worries than someone modifying the contents of your text books... Why would someone even want to do that?

Participating Frequently
June 17, 2021

Try67, I appreciate your reply.

 

I just want to know with 100% certainty that my .PDF files haven't been altered in the same way that I have 100% certainty that my physical books haven't been altered.

 

Is there a way for me to lock the .PDF files or make it impossible for them to be edited?

try67
Community Expert
June 17, 2021

Try67, I appreciate your reply!

 

I'm not familiar with "digitally signing the files"??? How does this work?

 

Let's say I have a completely legal and free .PDF file I have on a USB HDD: Is it possible for me to make it so that it cannot be changed forever? For example, that the .PDF file that's stored on a USB HDD cannot be changed in say, 2 years from now?


Open the file and go to Tools - Prepare Form and then use the Add New Field tool to draw a new signature field on the first page of the file. Close Prepare Form mode and click on this field. If you don't already have a signature profile, create one and save it as a file, backed by a password. Now apply this signature profile to your signature field and make sure to tick the box that says "Lock Document", and then save the file.

The next time you open this file you would be able to validate that it hasn't been modified by right-clicking the field and selecting Validate Signature. This will work in 2 years, 5, or 50.

Bernd Alheit
Community Expert
June 3, 2021

What kind of modification does you see?

Participating Frequently
June 3, 2021

Bernd,

 

I haven't seen any modifications yet, but I just want to know how I can be sure that my .PDF files haven't been modified?

 

:'(

Bernd Alheit
Community Expert
June 3, 2021

Put the files on a external drive and put the drive in a safe.