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GBDE-GEOM Based Disk Encryption on FreeBSD
BSD Forums writes "The ever increasing mobility of computers has made protection of data on digital storage media an important requirement in a number of applications and situations. GBDE is a strong cryptographic facility for denying unauthorised access to data stored on a 'cold' disk for decades and longer. GBDE operates on the disk(-partition) level allowing any type of file system or database to be protected. A significant focus has been put on the practical aspects in order to make it possible to deploy GBDE in the real world. FreeBSD's Poul-Henning Kamp says in an email to freebsd-current that he has uploaded this paper and slides which he presented at BSDcon 2003, California, USA."
When they have mascots like this?
I have over 70 freaks, do you?
For those of you who do not know. FileVault is data encryption for Panther (Mac OS X.3).
Netcraft confirms: "*BSD is encrypted and undead"
Now I understand the daemon logo.
FileVault is an encrypted disc image that is automatically mounted when you login.
It uses AES encryption (128 bit)
Its been written within Apple, using existing Apple technologies.
Using Disc Utility you can do the same on Jaguar, except Panther and FileVault make it very easy to do....
OpenBSD does not support SMP either.
BOO! TERRO
1. I highly doubt encrypted disks are Theo's idea.
2. Maybe not everyone wants to run OpenBSD.
You had me at "dicks fuck assholes".
If you read the article, you'd notice several things:
a) this is completely different from OpenBSD's implementation
b) it's portable across filesystems
c) you wouldn't have written this idiotic post.
Additionally, you obviously know nothing about cryptography, otherwise you'd not make such a stupid assumption about Rijndael, an OPEN algorithm developed outside the United States. It's been out for years and many people have failed miserably when trying to cryptanalyze it.
Additionally, it's also interesting to note that *NO* algorithms available in the mcrypt library are authorized for encryption of 'classified' data, by the NSA. Rijndael is authorized for encryption of 'highly sensitive' and some forms of 'classified' data.
Actually, the NIST and NSA are quite open with information about these algorithms.
Think before you speak.
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One of the cooler features that come with GBDE is the fact that you can encrypt CD-ROM images. This makes for a very secure way of getting someone a lot of sensitive data. A patch was recently posted on the current@ mailing list to allow this.
I suggest you actually read the paper and you'll see that this is not exactly the same. GBDE has far more security levels, is easier to setup and use and can be considered safer too. Again, read the paper to see what I'm talking about.
does gbde work with vinum yet?
This is great news for all those M16/CIA/etc agents how leave their laptops in the back of taxis!
I believe he is claiming Rijndael is a group. I don't have any data on that, but I find that quite hard to believe.
Pathman, Free (as in GPL) 3D Pac Man
There are some nice ideas and good thinking here, but does anyone have a link to more interesting performance numbers? I'm curious how well this would work on a workload that was both intense and non-sequential.
1) GBDE has been available for months. Had you talked about GEOM-Gate, now that would have been interesting.
2) Poul-Henning suffers from extreme NIH complex. This crypto support has been in OpenBSD for 2 years.
3) Do you think he will let anyone touch his code? He didn't for phkmalloc and that piece of shit called devd, what makes you think he will now?
Poul-Henning is probably the most arrogant person I've ever seen. He has negatively influenced FreeBSD in a way I cannot even describe. Now go and mod me down, because I now use NetBSD for all my machines.
Alan
Is this encryption deniable? If not - what's the point?
..."
What for for on a partition ? "Uh, no your honnor, that's not a partition full of encrypted pr0n, that's just some random free space that happens to take up most of my disk
"A door is what a dog is perpetually on the wrong side of" - Ogden Nash
How is this like rubberhose?
as a strong hash function.
I thought this was a bad idea, since RSA is non probabilistic. When used as a hash, you've got neither semantic security nor indistinguishability.
Didn't read what they used the hash for though.
How small a thought it takes to fill a whole life
This is not a new idea.
OpenBSD (vn* devices) and Linux (crypto-loop) have this for years. NetBSD also has it. Windows XP also has it.
Now FreeBSD introduces yet another implementation of the same thing.
This is great, but what about interoperability?
Right now, all operating systems I can use encrypted partitions, but the way they do it is different on every system.
If I encrypt my USB memory key on FreeBSD, I won't be able to use it on Linux. Even if the actual file system is the same, even if the encryption algorithm is the same.
This is illogical. Encrypted partitions are nice for small, portable devices, that you can plug on various hosts running various operating systems. That's the theory. But because everyone reinvents the wheel, you can't do that. It won't work.
Now that we have filesystems that almost any operating system out there has support for (ext2/ext3 and vfat), maybe it would be nice to use a common format for the encryption layer.
{{.sig}}
I have been working on article on disk encryption though it is not quite ready to be published yet. I didn't know anybody else was working seriously on this. I know about cryptoloop in Linux. It is bad, but not the worst I have seen described. It is nice to finally see somebody but me realizing that disk encryption is not as simple as those implementing it think. I don't know how the more "professional" products work. What I have realized is, that good disk encryption has an overhead on disk usage. Those "professional" products I have seen just a few details about doesn't have for too litle overhead for good crypto. The system described by the article only protects cold disks, no protection at all for hot disks. What I describe in my own article actually has some protection for hot disks, not much protection though, because the hot disk naturally limits the protection that is possible.
Do you care about the security of your wireless mouse?
Ok, when is this going to be ported to Linux kernel?
:)
This sure looks better than my current somewhat kludgy scheme of using Bestcrypt to mount different virtual drives.
And I just received my USB cryptoki token. Now, combine this disk encryption scheme, a good token for the keys, a good BIOS encryption (anyone has any info this?), the only thing left to do would be working on my good old tin foil hat now
Boy, you gotta love this kind of cross-polination among open source projects.
Rijndael, an OPEN algorithm developed outside the United States. ... by the NSA. Rijndael is authorized for encryption of 'highly sensitive' and some forms of 'classified' data.
While /. is USA-centric, surely what the NSA says doesn't bother the rest of the world... Quite handy that the NSA are open with information about these algorithms in fact ;-)
of this system, compared to others, is that it is so low level as to be filesystem agnostic.
As long as AES is considered to have decent security, this system could be used.
How small a thought it takes to fill a whole life
(Full disclosure: I've been involved with the Win32 Scramdisk project in the past)
Hhhm, this is pretty interesting. I am not aware of any other disk encryption program (Scramdisk, DriveCrypt, LoopAES, PGPDisk, BestCrypt etc) that offers sector remapping. It's useful because it prevents standard disk structures from being exploited in a known plaintext attack (note: with current knowledge, this is only a theoretical weakness with AES anyway).
Apart from that it looks a pretty standard On-The-Fly-Encryption (OTFE) system. It does appear to be slightly more complex than most programs, but this is offset by the peer review from (at least...) two very well respected cryptographers - Dr David Wagner and Lucky Green. I am not aware of any of the other OTFE systems being reviewed by anyone half this competent.
Last paragraph of 6 says "RSA2/512" should read SHA2/512.
I'd personally be worried about the use of a static (zero!) IV. I know the key is random, but.....Oh well, if Dr Wagner has peer reviewed it then this can't be much of an issue.
From the paper: "A truly paranoid setup would leave the computer con- figured to boot the Windows system by default, and locate the GBDE data in such a way that it would be destroyed by the act of doing so."
It's likely this wouldn't work - the first thing a half-competent adversary would do is image all disks in a system before booting....It's forensic 101.
"Mary had a crypto key, she kept it in escrow, and everything that Mary said, the Feds were sure to know."
No, cryptoloop in linux can not do the same. Cryptoloop can encrypt, but you can not change password. Luckily there are other ways to do that, PPDD which appears to be using the same princip of storing the real key on the disk, though encrypted with the password. The same princip a friend and me is using in our development of a device-mapper target, deadline is 1. october. .pdf's of the presentationslides, then i would state that GEOM appears to be very much what device-mapper is in Linux.
Not having any more knowledge of GEOM, than what i read in the
Very valid point. I hope someone addresses this. I supose it would be rather easy to write a device-mapper target that behaves like GBDE-GEOM
I believe it's an open question (see e.g. here)
"Mary had a crypto key, she kept it in escrow, and everything that Mary said, the Feds were sure to know."
Is this encryption deniable?
Yep - as per the paper, this encryption is deniable (that's to say there is no way of showing that the container file or partition is an encrypted volume without having the passphrase). Thinking of a good reason why you've got a very high entropy 2.5Gb file/partition when the cops kick the door down could be interesting though ;)
"Mary had a crypto key, she kept it in escrow, and everything that Mary said, the Feds were sure to know."
Additionally, you obviously know nothing about cryptography, otherwise you'd not make such a stupid assumption about Rijndael, an OPEN algorithm developed outside the United States. It's been out for years and many people have failed miserably when trying to cryptanalyze it.
Anybody who actually read and understood the AES proposal would know, that it is highly unlikely there could be any backdoor. Every design decision had a reason. Wherever multiple choices where available and no technical reason made one better than another, the final decission would be the one giving the least possibility for hiding any kind of backdoor. And BTW it was developed in Belgium.
Do you care about the security of your wireless mouse?
Lots of operating systems have had disk-at-a-time encryption. You can already get it for Windows, but that was apparently not good enough to have that PPT junkie use it either.
Disk-at-a-time (or file-system-at-a-time) encryption just doesn't seem to be convenient enough. Most files simply do not need to be encrypted, and the risk of losing an entire disk due to bugs or losing the pass phrase is just too high, as is the computational cost. People need to be able to decide on a per-file basis what gets encrypted and pick different pass phrases for different files.
In fact, file-at-a-time encryption shouldn't be in the kernel, it is implementable in user code if you have the right hooks. You can build that on top of Plan 9's file system hooks or on top of the CODA hooks in the Linux kernel. Something like the Plastic file system for Linux also would work. But it can also be done at the kernel level; ReiserFS may get file-at-a-time encryption soon.
By the way, if you do want disk-at-a-time encryption, StegFS strikes me as a better choice.
that's just some random free space that happens to take up most of my disk
Somebody once told me, that he kept a large file with random bytes on his HD, such that he could delete it if he was in an urgent need for more disk space and couldn't find anything else to delete.
Do you care about the security of your wireless mouse?
Is it possible to do that (instead of just keeping parts of the key on an usb storage device) with freebsd/GBDE?
I think some ibm thinkpad T30 come with TCPA chip which could (at least theoretically) work as such a token, too.
Seems to me that archives kept for decades should not be encrypted. Unless you keep the key right there with it, you're likely to loose it. Also, if there is degradation of the data you're likely to loose most of it even if you can find the key. Use physical access controls instead.
The paper explains this at length (but I guess that the respondent didn't actually read the paper). The primary focus in GBDE was usability and deployability. Most of the prior art in this space cannot even change the pass-phrase without reencrypting the entire disk (which can easily take an entire day).
I wanted to do better than that, and I think I did. By a wide margin.
RSA vs. SHA.
Correct, that is a typo, it is SHA2 which is used.
AES, zero IV etc.
An important part of GBDE is that there is no two-way leverage on any crypto component. This is realized by the use of single-use random bit sector keys. With no two-way leverage and single-use keys, the IV is no longer important.
The comment about the "plausible denial" setup being useless because an intelligent adversary would always take a mirror copy first: That does not affect the plausible denial aspect.
I'll be more than happy to discuss any aspect of GBDE, and would very much like to hear peoples experience and ideas. But I would prefer email (if need be by setting up a mailing list)
Poul-Henning Kamp -- FreeBSD since before it was called that...
Agreed, there are no published attacks on full Rijndael that are faster than trying all the keys.
Cryptanalysts normally develop their tools on weakened variants of an algorithm first, kind of like the way kittens practice hunting on mice their mother has already half-killed.
There are successful attacks on reduced-round variants of Rijndael. An impossible differential attack is faster than brute force for 128-bit Rijndael limited to 6 rounds (out of the normal 10) (Biham Keller 2000, Cheon et al 2001). The "Square Attack" (Lucks 2000, Ferguson et al 2000) works against 7 rounds of 192 or 9 rounds of 256 bit keys, at the cost of 2^224 encryptions.
If you're looking for a remotely practical attack you could say the researches "failed miserably", though that seems a bit harsh.
The people who really know crpyto are still comfortable with Rijndael for practical use. The fact that it's fast means it may actually *be* used. A cipher which gets used will provide security to more people than the theoretically unbreakable but problematic-to-use one time pad.
"Uh, no your honnor, that's not a partition full of encrypted pr0n, that's just some random free space that happens to take up most of my disk ..."
That is exactly the point of deniability.
Check out Rubberhose: http://www.rubberhose.org (the site seems to be down right now, but Google may have it cached - search for rubberhose.
With rubberhose, you create multiple virtual partitions each with their own key. Without knowing all the keys, there is no way to determine how many partitions their actually are. So, you can tell the judge two of your keys, and you can tell the judge that you only have two keys, and no one can tell whether or not there are more than two encrypted partitions on the disk.
If encryption is optional, then users might forget to encrypt a file that is sufficiently sensitive to warrant such protection. Moreover, if the swap file (or local equivalent) is not encrypted, some sensitive material might be recoverable by an unfriendly party.
I'm not really convinced by the cryptography in this paper. It's good that Wagner has read it but I wouldn't interpret that as meaning he's put his seal of approval on it.
Incidentally, I presented a paper on disk sector encryption at FSE 2000, you can read it here:
http://www.ciphergoth.org/crypto/mercy/
Xenu loves you!
You airhead, that's what I just said.
I said it's "an OPEN algorithm developed outside the United States". Are you being contradictory or needlessly pedantic?
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