Offline File Sharing Guide

Continuing the discussion from QR Scanner (PFA):

I’ve been wanting to write about this tool to ask this forum if there would be a interest to write a page/guide on privacy page about how to transfer data without interned / locally. Let’s call it Offline Sharing.

I wanted to share a link between my phone and my work computer and with this I was able to generate the code, then scan it using the laptop webcam and the camera app. I did not want to install work related app in my phone, nor connect to private account in my work computer to enable sharing. I thought a local qr to share a link would be a fast way to do that.

In a world where most sharing is done in onedrive and dropbox, most people probably don’t know how to share files locally.
The idea about this Offline sharing category is to educate a younger generation only used to phones and tablets.

We could have some explanation about

  • qr codes
  • bluetooth (for contact and files)
  • nfc between two phones for small data like website link, contact, etc
  • android quick share, for bigger files
  • some chat/messenger has a peer to peer function that works without internet (briar seems to fit, haven’t tested)

I’m not sure if it’s needed : maybe it would be adding unneeded diffficulty. Cloud sharing did become the popular solution, maybe because of the ease of uses vs other competing technology. Maybe simply using better cloud (ente, proton) is suffficent for most people.

I’ll watch your opinions, thanks

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For some reason you haven’t mentioned actually, completely offline ways to share such as SD cards or USB drives. If you have a USB A-to-C adapter you can use your USB A drive to transfer files to your phones (assuming they have USB C ports).

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IIRC, you can even use direct USB-C to USB-C but that seems to be outside my technical knowledge.

I was thinking about this as well.

It just seems so easy for a malicious person to copy some malware/trojan/virus onto a USB drive and then pass it over to a friend and BOOM as soon as the USB is connected to a Windows PC it’s able to dig its claws into the PC and install keyloggers etc.

It seems much easier to spread malware/trojans/viruses via USB as opposed to the Internet.

My fear:
I was worried about buying new USB drives and USB hubs because of this but it seems unlikely that a brand new USB drive or USB hub from a well known vendor like Belkin, Targus, Amazon etc would do this???

This is a very unrealistic threat imo. I mean, if you have a buddy that’s gonna hand you a USB with malware on it purposefully, they’re not your buddy…

Also, if hardware storage providers were shipping drives with Trojans on them willy nilly, there would certainly be legal repercussions. There is 0 incentive for them to do this.

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I appreciate your reply!

I think you’re 100% correct on this… It’s not worth even thinking about it or factoring it into how secure USB hubs/USB Drives/devices are to be honest.

**I still think there’s a big threat with inserting USB drives/USB drives from people you barely know… I guess a Linux PC wouldn’t need to worry about this but for a Windows 10/11 PC? I think there’s a huge threat!

I once got a USB from a telecoms company in my country and it had a trojan lol.

There you go… I know pre-internet days viruses promulgated via floppy disks.

I can’t see how USB drives are any safer than floppy disks?

Hi all
I did not talk about usb sharing because the topic was more geared torwards mobile user. Sharing with usb key or phone to phone is still available, but it requires file system / file management knowledge and not everyone has those nowadays unfortunately. I write android quick share above as a replacement without cable and hopefully more user friendly.

Have you thought of using local network sharing?

There is a app on fdroid called ShareX (Github - ShareX) that sets up a local server and uses the phones hotspot functionality. You then connect with another phone or computer to the hotspot and enter the generated url (example: http:// 10.0.2.16:6060). This way you can transfer files both ways, and works without internet. Can also be used so that the phone with the hotspot allows two or more other devices to send files through the phone.

I also don’t think autorun is even a thing anymore by default, in pretty much any OS. The malicious actor would need a zero day

Does anyone know more about this?

Could be from the old hey day of the USB drives.

A lot of people back then had a nasty autorun.inf file set to run loose until the USB drive protector was a thing (IIRC the very last writable bit was set to be the start of the autorun.inf so that it would not be writable at all)

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I appreciate your reply!

I’ve been searching PrivacyGuides but I can’t find much regarding secure data storage on DVD discs and Blu-Ray discs.

Are DVD discs and Blu-Ray discs a viable option instead of using USB drives?

The benefit with DVD discs and Blu-Ray discs is that you can buy blank discs that can only be written to once which means the data, for example ebooks and personal notes, cannot be altered and the discs are cheap.

Does anyone know?

With the flexibility of linux, in the past I was burning luks encrypted bluray drive. You would put them in a linux machine, and they would be recognized as luks, asked a password through the file manager and decrypted very easily.

Nowadays I don’t burn anymore, its kind of a time loss. At some point I simply buyed two drive of the same size, formatted with two different file system, then copied the files to it.

I dont think there is much value with your example like ebook or personal note to be read-only from a dvd disk.
A good encryption of a hard diak (bitlocker,luks or other), will make your file pretty safe against modification against most thread (lets stay realiatic here)

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I appreciate your reply!

Using Blu-Ray/DVD Read Only disks seem like an awesome way to backup because once the data is written to disk it cannot be altered or changed in any way as long as the blu-ray/DVD disks are “Read only”. I know you can set files on USB drives to be read “Read only” but this is only a software solution.

In the case of blu-ray/DVD discs it’s a hardware solution.

It might be safer to only use DVD blanks as blu-ray external/internal drives never had much success, but it’s still a good option.

I did some research for you and even though Blu-ray doesn’t have nearly the penetration that DVD discs had, but blu-ray discs are still cheap: 25GB 5pack for $30

EDIT:

In case you’re worried about longevity I just found these DVD-M blanks that are rated for 1,000 years: https://www.newegg.com/millenniata-4x-4-7gb-m-disc/p/12Z-001K-00019?srsltid=AfmBOooexCKKRba9-OUSqoKEYk5Gj97h27_VuOF3dcyzV0H30JpZV_xX

The theorical 1000 years of lifetime has nit been tested in real-world condition. I have real dvds (standard ones) that had issue after less than 5 years, and other starting to have issue after 15 years.

There is also the availability of the underlying technology. Do you think Dvd drive will still exists and will be broadly supported in 30 years ? Dvd is almost dead now, so I have low confidence in 10 and 20 years. Thsts why I migrated my dvd to disk. I also migrated my floppies to disk, before they dies too.

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Those M-disks are rated at 1000 years… but are the M-disk readers rated the same? The only way for it to perpetuate for that long is that if the standards and parts are completely open and firmly in the public domain. Otherwise the device manufactures and parts are at risk of dying out.

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I appreciate your replies!

That’s true about DVD’s becoming obsolete in the future, but it just seems DVD players/DVD Drives USB devices are much, much more popular and much cheaper than blu-ray USB devices.

I like the idea of keeping a backup on a medium like DVD’s that can’t have their data changed. Data on a USB HDD can always be edited in the future…