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Comment by nxobject | Hacker News Reader

If the encryption was that easy to bypass, was it worth it at all?

The manufacturer didn’t even know encryption was enabled, because as long as the camera was working, it would just provide all files over USB without any encryption.

It was basically enabled by accident, and the only thing it prevented was recovery of files directly from the SD card when the camera was damaged.

There are some reasons you'd want to encrypt even without a secret key. One is it makes it easier to erase data (just erase the key).

It also makes bit flip errors a lot more obvious, which is another way of saying harder to ignore, so that can go either way.

Can't bit flip errors also destroy encrypted volumes much more easily?

I think it depends. Encrypted filesystems typically encrypt contents of each file separately - that way you don't need to read / write the whole disk to read it write any individual file contents. Of course that means metadata may be in plain text or may be separately encrypted - again possibly folder by folder instead of all metadata at once. Exact details would vary with different file system encryption schemes.

Whereas if you image the disk and encrypt the image properly, that gives you all the great confidentially guarantees but no random access.

> Encrypted filesystems typically encrypt contents of each file separately - that way you don't need to read / write the whole disk to read it write any individual file contents.

Ah, that's not true of "full disk encryption". It usually encrypts the disk blocks.

File-based encryption is stronger; you can use different protection classes on different files, you can use authenticated encryption, etc. iOS does it this way and I assume other systems have caught up, but don't know any in particular.

File-based encryption leaks metadata (which in some cases is bad enough to render it unusable).

No one said you had to leave the FS itself unencrypted.

Most FDE systems are not authenticated so you would only lose one block (16 bytes for AES). Can this be bad? Yeah, but it's not that bad for data recovery.

Not to mention that most drives start having issues with dead sectors rather than bitflips, and that's (usually) 4K.

Encryption does not make bit flips obivous, authenticated encryption would.

A single bit flip would mess up the block, and hopefully the rest of the stream and the padding, no?

Most unauthenticated encryption modes only mess up a few bits of a block, sometimes the following block too. A few only flip the exact bit in the plaintext.

Sure. If the card was recovered without the camera motherboard then the decryption key would not have been recovered.

Stealing a camera is much harder than stealing an SD card out of a camera.

Citation needed. It might be slightly easier, but most cases where you can get part of the camera, you can get the whole camera. This isn't a little point-and-click with a handy spring-loaded slot either.

Yeah but the Camera's owner is much more likely to notice "my camera is missing" than "the SD card is blank for some reason... the SD card must have failed"

EDIT: The linked PDF has a photo, the camera literally opens up to access the SD card.

The camera's (former) owner may very well notice, but that will have little effect. It's much more common that cameras (security, photography, phones) get stolen with cards inside, rather than someone extracting the card and leaving the camera.

This is professional equipment, used for surveys. Think espionage, not consumer hardware.

Worth mentioning that I would immediately know if a different SD card was in my camera the moment I turned it on or ejected the card. If somebody knew to buy the same exact model and storage size that would be truly impressive.

Industrial espionage is far far more often done by hard work then being clever. Checking the SD cards you use and buying matching ones before executing a swap isn't noteworthy.

If you look through my case of SD cards I have all sorts of sizes and makes/models. I also have a procedure for dumping and formatting, and someone who is handling this most likely would as well. The moment the storage on screen looks funny or I see the card I don’t recognize, I’ll notice.

I’m not saying it’s impossible or I’m somehow immune to being tricked, but you would be surprised how easy it is to leave evidence of tampering through the simple act of trying to take an SD card, whether you swap it out or not. And people like me who handle them regularly would likely notice it in a split second. Maybe we won’t even catch the perpetrator, but it would not be written off as “oh interesting I guess it didn’t record,” if for no other reason then I would go straight into CYA mode and start looking for any hint that I didn’t make a mistake.

At that point if you have a basic security SoP in place and adhere to it you can start auditing.

Anywho again nothing is airtight and a determined individual could of course get past me. But you would be surprised how many hurdles they have to get over, and it certainly wouldn’t go unnoticed and be brushed off as a read/write quirk, that’s really all I’m saying

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