Hardware encrypted USB drives - Extra Security or Extra Liability?

Recondite49

I bought this little gem on Amazon a couple of months ago and wanted to ask your thoughts on this and hardware encrypted USB sticks in general.

The main advantage of the Corsair is that it's very simple to set up and use. In theory at least all data on the stick is protected via 256 Bit AES encryption. (Corsair have now corrected the vulnerability in their USB sticks which previously allowed this to be bypassed very easily with a bit of solder and a resistor).

My original plan was to install an encrypted operating system to the USB stick but for whatever reason whenever I unlocked the drive, the machine failed to boot from it. (I'm perfectly willing to put this down to my own incompetence!).

Needless to say as a security conscious person, this would have to be used in addition to software encryption and keeping the USB device physically safe.

However I have since honorably retired the stick to my book shelf in favour of software encryption, mainly due to reading this article which points out the drawbacks to this and other hardware encrypted USB sticks, which can be briefly summarised here:

- The data is protected by a numeric PIN. Even a ten digit one doesn't provide very much entropy and can be cracked in a viable amount of time.

- With reference to the above, the device has a timer which delays entry of a new PIN by three minutes every time it's entered incorrectly three times. This is quite a common feature on these devices but can easily be bypassed by opening up the drive and removing the EPROM chip, whereupon you can crack away to your heart's content.

- Resetting the PIN supposedly erases the drive but it's potentially possible to recover fragments of the underlying data. Very unlikely the USB stick deletes files in a secure manner, particularly as this is flash memory.

- No plausible deniability for encryption. Enough said. Having said this, a very shrewd person could use the stick to store some dummy encrypted data and meekly hand this over when required.


Having said this, it is excellent proof against software keyloggers, evil Maids attacks and so on.

Has anyone else had experience with hardware encryption like this? Perhaps there's a device which can get around these concerns?

Blowfish

We used to use hardware encryption based keys in our place before we moved to software a while back. Primary reasons for switching to software were applicable for enterprises, but not really so much for home/personal use, i.e. we wanted central management, port control, audit logging etc.

One of the models we used were these. They, like lots of others have a small unencrypted partition with the software needed to unlock the larger hardware encrypted bit. Advantages over the one you listed are that it's a full alphanumeric key (albeit limited to 16 chars) and if entered 6 times incorrectly will (so they claim) wipe the data and previous encryption key to prevent brute forcing.

It's primary drawback and the reason why I don't make use of the bunch left over after the switch is that it supports Windows only.

Recondite49

Blowfish wrote: »

We used to use hardware encryption based keys in our place before we moved to software a while back. Primary reasons for switching to software were applicable for enterprises, but not really so much for home/personal use, i.e. we wanted central management, port control, audit logging etc.

One of the models we used were these. They, like lots of others have a small unencrypted partition with the software needed to unlock the larger hardware encrypted bit. Advantages over the one you listed are that it's a full alphanumeric key (albeit limited to 16 chars) and if entered 6 times incorrectly will (so they claim) wipe the data and previous encryption key to prevent brute forcing.

It's primary drawback and the reason why I don't make use of the bunch left over after the switch is that it supports Windows only.

Thanks Blowfish, these look much more promising! The Achilles heel as you say seem to be the fact that supporting it only on Windows platforms means that they're much more vulnerable to malware.

Forgive my ignorance also but in what sense is the encryption hardware based if it's managed from a software partition? Perhaps I am splitting hairs but I couldn't see the advantage this would offer over a software encrypted USB stick?

I don't mean to take the mickey, I just couldn't take it in from the website.

hmmm

What are you defending against?

For a business facing the risk of accidental loss, a hardware encrypted device is an excellent choice. If it's lost, there is 100% certainty the data is encrypted, and you are not expecting a super sophisticated attack to try and access the data. Software encryption is prone to failures, in particular the user doing something stupid (e.g. storing data outside an encrypted partition).

If you're defending yourself from the NSA, well then yes perhaps there is weaknesses in the hardware. Or possibly one of their offshoot companies has made the device in the first place.

Recondite49

hmmm wrote: »

What are you defending against?

For a business facing the risk of accidental loss, a hardware encrypted device is an excellent choice. If it's lost, there is 100% certainty the data is encrypted, and you are not expecting a super sophisticated attack to try and access the data. Software encryption is prone to failures, in particular the user doing something stupid (e.g. storing data outside an encrypted partition).

If you're defending yourself from the NSA, well then yes perhaps there is weaknesses in the hardware. Or possibly one of their offshoot companies has made the device in the first place.

Hi hmmm,

While I applaud anyone who considers their threat model, I've always like to assume that any adversary has the time and resources of the NSA to get at my data and proceed from there. It's true that could be seen as overly paranoid, but it's worked as a policy so far!

As you say the beauty of hardware encryption is that there's zero possibility of storing data in the wrong place. Of course this is mooted slightly if you encrypt your entire operating system in the first place but I agree it's a much safer in terms of human error.

It's not inconceivable that the NSA or similar could influence a company to weaken their encryption as we know this has already been done. Provided the standard is an open one though, I imagine this would be picked up by the community at large, like the weakness with RC4 was?

The one consolation I have is that nothing on the drive can be examined covertly. It would have to be confiscated and cut open to get to the EPROM chip within - an Evil Maid attack wouldn't stand much of a chance unless they could do all that and leave the drive looking intact.

At the moment I use the stick only to keep encrypted backups of my Bitcoin, Litecoin and Darkcoin wallets. This is proof against thieves and even if the Police did get their grubby mitts on them it's not the end of the world because they're not the only copy.

syklops

Recondite49 wrote: »

edited out picture for Khannie's nervies :pac:

I bought this little gem on Amazon a couple of months ago and wanted to ask your thoughts on this and hardware encrypted USB sticks in general.

The main advantage of the Corsair is that it's very simple to set up and use. In theory at least all data on the stick is protected via 256 Bit AES encryption. (Corsair have now corrected the vulnerability in their USB sticks which previously allowed this to be bypassed very easily with a bit of solder and a resistor).

My original plan was to install an encrypted operating system to the USB stick but for whatever reason whenever I unlocked the drive, the machine failed to boot from it. (I'm perfectly willing to put this down to my own incompetence!).

Needless to say as a security conscious person, this would have to be used in addition to software encryption and keeping the USB device physically safe.

However I have since honorably retired the stick to my book shelf in favour of software encryption, mainly due to reading this article which points out the drawbacks to this and other hardware encrypted USB sticks, which can be briefly summarised here:

- The data is protected by a numeric PIN. Even a ten digit one doesn't provide very much entropy and can be cracked in a viable amount of time.

- With reference to the above, the device has a timer which delays entry of a new PIN by three minutes every time it's entered incorrectly three times. This is quite a common feature on these devices but can easily be bypassed by opening up the drive and removing the EPROM chip, whereupon you can crack away to your heart's content.

- Resetting the PIN supposedly erases the drive but it's potentially possible to recover fragments of the underlying data. Very unlikely the USB stick deletes files in a secure manner, particularly as this is flash memory.

- No plausible deniability for encryption. Enough said. Having said this, a very shrewd person could use the stick to store some dummy encrypted data and meekly hand this over when required.


Having said this, it is excellent proof against software keyloggers, evil Maids attacks and so on.

Has anyone else had experience with hardware encryption like this? Perhaps there's a device which can get around these concerns?

If this is just sat on a shelf at home, I'd be happy to take it off your hands. I go into a lot of secure environments and unfortunately I sometimes have to use USB sticks myself. This would tick many of the requirements I need. That is to say, in a lot of cases, I am not protecting data from the NSA, I am protecting my own ass. Accidentally leaving behind an unencrypted USB stick with data belonging to my employer or my client(or another client), could be disastrous if found and opened. Something with built in hardware encryption would tick a lot of boxes for me.

Blowfish

Recondite49 wrote: »

Forgive my ignorance also but in what sense is the encryption hardware based if it's managed from a software partition? Perhaps I am splitting hairs but I couldn't see the advantage this would offer over a software encrypted USB stick

I haven't looked into it too much as the choice to use them was before my time and we've since moved on, but I'd imagine it wouldn't be too far off how OPAL compliant HDD's work, i.e. the software hands the key off to the equivalent of a disk controller which checks it and if valid does the actual unencrypting, seperate from the machines CPU.

hmmm wrote: »

Software encryption is prone to failures, in particular the user doing something stupid (e.g. storing data outside an encrypted partition).

If you are relying on unmanaged software encryption, then yes, but there are a good few enterprise level solutions which prevent that.

The one we use for example has an agent that runs on startup so that as soon as you plug a key in, you get an option to do a full disk encryption. If you decide not to, the data is only accessible as read only (after the automated AV scan naturally). If you decide to encrypt, it'll first do the pw setup, then it'll copy any existing data to HDD temporarily, make the key read only for the user, create an encrypted partition using the space, mount it as a separate drive and copy the original data back onto it.

The other major problem you have with just hardware based keys is you are relying on your users to actually use them, rather than using their own stuff. With any decent software solution you can force encryption on any device as well as block by port (sdcard/bluetooth/firewire etc.) and by category (phone/camera, hell even printer if you wanted to).

[edit] Actually I completely forgot that when I was looking into this I was sent a hardware device with pin as a 'sample', much like the one in the OP. Must check if I still have that, could be useful for my own personal use.