[dm-crypt] LUKS & TrueCrypt - Speed Test

["Jorge Fábregas" <jorge.fabregas@gmail.com>]

Hello everyone,

Inspired by this old blog post:

http://movingparts.net/2007/10/26/truecrypt-versus-luks-speed-test/

...I decided to perform some tests on my Fedora 14 box.   This is not a
pro benchmark so be warned :)

Common Facts for both tests:

- source & destination filesystems were ext4
- destination is an external USB drive
- source data size is 143GB (a folder with lots of files & directories,
small & large files, regular data...)
- rsync was used to perform the actual copy
- I'm using an "encrypted partition " (against an encrypted file)
- I did a test first with TrueCrypt and then with LUKS
- Between the above tests, I shut down the machine (to flush filesystem
cache).
- my system kernel: 2.6.35.13-92.fc14.i686

### TrueCrypt Results ####
I used AES-256 (XTS operation mode), hash algorithm: ripemd-160 and the
package was realcrypt-7.0a-1.fc14.i686

Output of time command after rsync finished:

real	105m22.211s
user	28m10.471s
sys	41m35.319s


### DM-Crypt LUKS Results ###
I used the defaults:  AES-256 (CBC), sha1 for header hashing and the
package cryptsetup-luks-1.1.3-1.fc14.i686

Output of time command after rsync finished:

real	108m55.291s
user	28m6.534s
sys	42m53.400s


As you can see, there's almost a 4 minute difference.  I was expecting
LUKS to be faster (as dm-crypt is a kernel module) and TrueCrypt runs
mainly in user space isn't it?  Do you think the cipher operation modes
(XTS vs CBC) played a role in this difference? Have any of you performed
a similar test?

Regards,
Jorge