on Thu, Jul 05, 2001 at 10:08:42AM +0100, Neill Newman scribbled:

That is correct, it was me, I had no problems with the kerneli patch.. now, getting encrypted file systems set up was a different story!! it took me ages to get it working!!!

Something like this worked for me:

# dd if=/dev/urandom of=/mycfs bs=1m count=$size

# modprobe $cipher # losetup -e $cipher /dev/loop0 /mycfs (prompts for key) (add more layers here if needed - by incrementing the loop device and using the previous loop device as the second parameter..)

# mkfs.ext2 /dev/loop0 # mount -o noauto,nosuid,nodev,rw,loop,exec /dev/loop0 /cryptofs

where $size is the fs size in megs and $cipher is the main cipher you wish to use. I'm pretty sure this is all in a howto somewhere.. If you're doing multiple cfs, then remember the -o *loop* to mount ties up another /dev/loop device.

Problems you can come across are with losetup, such as it not being up to date enough to recognize your cipher. iirc you can just download and install the losetup from a later util-linux. losetup -h should list the supported ciphers.

--- Andrew J Glover flexifoil@btinternet.com wrote:

...

Something like this worked for me:

[snip]

...

I'm pretty sure this is all in a howto somewhere.. If you're doing multiple cfs, then remember the -o *loop* to mount

ties up

...

another /dev/loop device.

Yeah, read the howto, got all that, thanks.

Im just trying to decide on a cipher atm. I guess its a choice of Blowfish, IDEA, or serpent. Blowfish being good and fast, IDEA being

better but slower than blowfish, and serpent looking good but not really tested against.

Anyone got any opinions on them? I doubt i'll get much response, its

pretty much a personal choice I guess.

I seamed to have missed the beginning of this thread so I assume its something about secure filesystems.

Being a sad nerd who has read Cryptonomicon, the code book and applied cryptography too many times I have been looking at secure file systems. I was looking at a 128mb disk which is stored on the harddisk as shutdown but which is mounted into ram on boot up, so I get a steganographic Ram disk? Does anyone know if this is possible?

Also you mention blowfish, what about twofish? or pontifex?

On an unrelated note, what was that library system being talked about a couple of weeks ago?

The library system is something which shall be filed under "Don't mention the war"

Thanks

D

Thanks,

Andrew.

===== -------------------- "We all know Linux is great... it does infinite loops in 5 seconds." Linus Torvalds

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on Thu, Jul 05, 2001 at 01:31:02PM -0700, David Freeman scribbled:

I seamed to have missed the beginning of this thread so I assume its something about secure filesystems.

Being a sad nerd who has read Cryptonomicon, the code book and applied cryptography too many times I have been looking at secure file systems. I was looking at a 128mb disk which is stored on the harddisk as shutdown but which is mounted into ram on boot up, so I get a steganographic Ram disk? Does anyone know if this is possible?

Yes, but what happens if you have a power cut or some other crash? ups i guess.

You can get the stegfs patches and utils from http://www.mcdonald.org.uk/StegFS/ although last time I tried it, it wasn't very stable - could have just been me and it was 1999/2000. Then simply compile a kernel with ramdisk support, grab srm/smem by thc. http://packetstorm.securify.com/groups/thc/ is the most working url I can find at the moment..

So at boot up you just: 0) dd if=/stegramfs of=/dev/ram0 bs=1m count=128 (might be ramdisk size issues here..also might want to store it more encrypted) 1) mount (params) /dev/ram0 /somefs 2) srm /stegramfs 3) use stegfs stuff later to access it

and shut down: 0) umount /dev/ram0 1) dd if=/dev/ram0 of=/stegramfs bs=1m count=128 2) smem