SERIOUS Help Needed: Best Open Source PDF Reader For User Privacy?

FatGuy · 02-21-2023, 02:18 PM

Hello everyone, I need advice. This problem has been on my mind for a very long time.

I'm just looking for the most secure and privacy friendly PDF reader for cross-platform use.

My huge worry is that the PDF reader App I'm using will "call home" to someone on the Internet and upload information on what I'm reading on the PDF reader App. It could also transmit other types of data on the particular device I'm using whether it's my PC/Mac/Android/iPad.

I've done a lot of research and it seems like these two open source PDF readers are clear standouts when it comes to user privacy and security: XPdfReader and Sumatra PDF:

https://www.xpdfreader.com/

https://www.sumatrapdfreader.org/free-pdf-reader

Thank you for any suggestions!

FatGuy · 02-21-2023, 02:23 PM

I forgot to say that I've come down to these two choices because they're both open source Apps!

Sirtel · 02-21-2023, 02:30 PM

I've used Sumatra for years. No issues. But then I don't read PDF files often, and those I've read were not any kind of sensitive material.

j.p.s · 02-21-2023, 02:46 PM

xpdf has been my primary PDF viewer for many years.

I sometimes use evince, which doesn't have as nice UI and isn't quite as cross-platform, becuase it can fill PDF forms.

Kindleing · 02-22-2023, 03:16 AM

It seems to me if you have a serious need to prevent your reading list from being disclosed, you need to pay attention to the whole system, not just the reader app. For example, remember a few years ago Adobe was caught uploading the titles of all ebooks on a device through their ADE app, regardless of its origin? When caught, they said it was to verify licenses, but when questioned why they were "verifying licenses" for titles outside the ADE system they backtracked and claimed it was a "bug".

There is also the issue of current operating systems like Windows 10 & 11 "telemetry" uploading inventories of user content. Supposedly this can be disabled, but I believe it is enabled by default and the settings can be levels deep and confusing.

My suggestion would be to set up a restricted operating system on a single device and use that for your private reading material. Side load everything and never let it on the Internet. You can even go so far as to physically diable the WiFi and ethernet connections. Many Panasonic Toughbook laptops have a physical switch to disable WiFi so it can't be enabled accidentally. Older laptops and tablets are available at reasonable prices; not much horsepower is needed for a reader app.

You can use a reasonably secure operating system like TAILS (Linux) on a modest laptop. Or you could start with a fresh installation of Windows or whatever you prefer, do all the updates, and then disable Internet connectivity. Then side load everything.

Modern operating systems have made this issue very difficult to resolve. Serious security is hard, and is truly inconvenient. I'm certainly no expert, but I've come to the conclusion that an air-gapped system is the only thing that approximates what you are after.

brouer · 02-26-2023, 01:08 PM

On Windows/Linux, I like Okular.
Official builds are even published to the Microsoft Store.

rcentros · 02-26-2023, 05:55 PM

Quote:

Originally Posted by j.p.s

I sometimes use evince, which doesn't have as nice UI and isn't quite as cross-platform, becuase it can fill PDF forms.

I use Atril, but it's just a fork of Evince.

FatGuy · 03-06-2023, 01:58 PM

Wow, I really appreciate all of your responses!

Sorry I took so long to reply but my life has been very hectic!

I've been doing more research and it seems like Xpdf or Sumatra are the two best options for privacy and security because they're open source, however, it says here that Xpdf is closed source??? https://www.xpdfreader.com/opensource.html

I'm leaning towards Sumatra more now...

j.p.s · 03-06-2023, 02:46 PM

XpdfReader is a closed source enhanced version of xpdf. I have no experience with it.

xpdf itself is completely open source and is my favorite PDF reader.

Is there some feature of XpdfReader that you need?

FatGuy · 03-21-2023, 06:39 PM

Quote:

Originally Posted by j.p.s

XpdfReader is a closed source enhanced version of xpdf. I have no experience with it.

xpdf itself is completely open source and is my favorite PDF reader.

Is there some feature of XpdfReader that you need?

Thanks so much for your reply!

I don't need any particular features from XpdfReader, I just severely need a PDF reader that I can trust is looking after my privacy and security.

EDIT:
I really want to make a choice for which PDF reader I ought to use that will protect my privacy so I can make progress

j.p.s · 03-21-2023, 06:57 PM

Quote:

Originally Posted by FatGuy

Thanks so much for your reply!

I don't need any particular features from XpdfReader, I just severely need a PDF reader that I can trust is looking after my privacy and security.

EDIT:
I really want to make a choice for which PDF reader I ought to use that will protect my privacy so I can make progress

Is there some reason you can't use xpdf? (As opposed to XpdfReader.)

Note that I don't use windows or mac so I can't address what would or wouldn't work for them.

brouer · 03-22-2023, 03:26 AM

If privacy is the overriding concern, I'd pick Okular.

From KDE's privacy policy:

Some software produced by the KDE Community may include telemetry components, which provides details on the device it's running on to us. Where this functionality exists, it will always operate on an opt-in basis and be disabled by default, with the ability to change your preferences at any time.

FatGuy · 04-08-2023, 05:10 PM

Quote:

Originally Posted by j.p.s

Is there some reason you can't use xpdf? (As opposed to XpdfReader.)

Note that I don't use windows or mac so I can't address what would or wouldn't work for them.

Thanks so much for your reply!

I'm just looking for a PDF reader I can trust with my personal information. I figured that open source would be the best way to go...

I sincerely hope I can find a solution to my problem because this is really holding me back from reading PDF files

meeera · 04-19-2023, 10:47 AM

Quote:

Originally Posted by FatGuy

I'm just looking for the most secure and privacy friendly PDF reader for cross-platform use.!

If your use is that sensitive, I suspect what you need to do is a wired sideload onto a device that is permanently in airplane mode.

FatGuy · 04-21-2023, 02:26 PM

Quote:

Originally Posted by meeera

If your use is that sensitive, I suspect what you need to do is a wired sideload onto a device that is permanently in airplane mode.

Thanks so much for your reply!

Can you explain your idea a bit more? I just want to "lock down" a PDF reader so that it cannot send data back to the Internet.

02-21-2023, 02:18 PM	#1
FatGuy Groupie Posts: 157 Karma: 1804362 Join Date: Nov 2014 Device: iPad Mini 3	SERIOUS Help Needed: Best Open Source PDF Reader For User Privacy? Hello everyone, I need advice. This problem has been on my mind for a very long time. I'm just looking for the most secure and privacy friendly PDF reader for cross-platform use. My huge worry is that the PDF reader App I'm using will "call home" to someone on the Internet and upload information on what I'm reading on the PDF reader App. It could also transmit other types of data on the particular device I'm using whether it's my PC/Mac/Android/iPad. I've done a lot of research and it seems like these two open source PDF readers are clear standouts when it comes to user privacy and security: XPdfReader and Sumatra PDF: https://www.xpdfreader.com/ https://www.sumatrapdfreader.org/free-pdf-reader Thank you for any suggestions!

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02-21-2023, 02:23 PM	#2
FatGuy Groupie Posts: 157 Karma: 1804362 Join Date: Nov 2014 Device: iPad Mini 3	I forgot to say that I've come down to these two choices because they're both open source Apps!

02-21-2023, 02:30 PM	#3
Sirtel Grand Sorcerer Posts: 10,146 Karma: 224760044 Join Date: Jan 2014 Location: Estonia Device: Kobo Sage & Libra 2	I've used Sumatra for years. No issues. But then I don't read PDF files often, and those I've read were not any kind of sensitive material.

02-21-2023, 02:46 PM	#4
j.p.s Grand Sorcerer Posts: 5,285 Karma: 98804578 Join Date: Apr 2011 Device: pb360	xpdf has been my primary PDF viewer for many years. I sometimes use evince, which doesn't have as nice UI and isn't quite as cross-platform, becuase it can fill PDF forms.

02-22-2023, 03:16 AM	#5
Kindleing Groupie Posts: 169 Karma: 9105112 Join Date: Sep 2010 Location: Washington State, USA Device: Kindles & Kobos	It seems to me if you have a serious need to prevent your reading list from being disclosed, you need to pay attention to the whole system, not just the reader app. For example, remember a few years ago Adobe was caught uploading the titles of all ebooks on a device through their ADE app, regardless of its origin? When caught, they said it was to verify licenses, but when questioned why they were "verifying licenses" for titles outside the ADE system they backtracked and claimed it was a "bug". There is also the issue of current operating systems like Windows 10 & 11 "telemetry" uploading inventories of user content. Supposedly this can be disabled, but I believe it is enabled by default and the settings can be levels deep and confusing. My suggestion would be to set up a restricted operating system on a single device and use that for your private reading material. Side load everything and never let it on the Internet. You can even go so far as to physically diable the WiFi and ethernet connections. Many Panasonic Toughbook laptops have a physical switch to disable WiFi so it can't be enabled accidentally. Older laptops and tablets are available at reasonable prices; not much horsepower is needed for a reader app. You can use a reasonably secure operating system like TAILS (Linux) on a modest laptop. Or you could start with a fresh installation of Windows or whatever you prefer, do all the updates, and then disable Internet connectivity. Then side load everything. Modern operating systems have made this issue very difficult to resolve. Serious security is hard, and is truly inconvenient. I'm certainly no expert, but I've come to the conclusion that an air-gapped system is the only thing that approximates what you are after.

02-26-2023, 01:08 PM	#6
brouer Enthusiast Posts: 31 Karma: 47570 Join Date: Sep 2011 Location: .dk Device: Various Android devices	On Windows/Linux, I like Okular. Official builds are even published to the Microsoft Store.

03-06-2023, 01:58 PM	#8
FatGuy Groupie Posts: 157 Karma: 1804362 Join Date: Nov 2014 Device: iPad Mini 3	Wow, I really appreciate all of your responses! Sorry I took so long to reply but my life has been very hectic! I've been doing more research and it seems like Xpdf or Sumatra are the two best options for privacy and security because they're open source, however, it says here that Xpdf is closed source??? https://www.xpdfreader.com/opensource.html I'm leaning towards Sumatra more now...

03-06-2023, 02:46 PM	#9
j.p.s Grand Sorcerer Posts: 5,285 Karma: 98804578 Join Date: Apr 2011 Device: pb360	XpdfReader is a closed source enhanced version of xpdf. I have no experience with it. xpdf itself is completely open source and is my favorite PDF reader. Is there some feature of XpdfReader that you need?

03-22-2023, 03:26 AM	#12
brouer Enthusiast Posts: 31 Karma: 47570 Join Date: Sep 2011 Location: .dk Device: Various Android devices	If privacy is the overriding concern, I'd pick Okular. From KDE's privacy policy: Some software produced by the KDE Community may include telemetry components, which provides details on the device it's running on to us. Where this functionality exists, it will always operate on an opt-in basis and be disabled by default, with the ability to change your preferences at any time.

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