Re: Announce loop-AES-v3.0b file/swap crypto package

From: Bill Davidsen (davidsen_at_tmr.com)
Date: 01/20/05

  • Next message: Ingo Molnar: "Re: [patch 1/3] spinlock fix #1, *_can_lock() primitives"
    Date:	Thu, 20 Jan 2005 11:42:11 -0500 (EST)
    To: Fruhwirth Clemens <clemens@endorphin.org>
    
    
    

    On Wed, 19 Jan 2005, Fruhwirth Clemens wrote:

    > On Wed, 2005-01-19 at 12:03 -0500, Bill Davidsen wrote:
    > > On Tue, 18 Jan 2005, Dan Hollis wrote:
    > >
    > > > On Tue, 18 Jan 2005, Venkat Manakkal wrote:
    > > > > As for cryptoloop, I'm sorry, I cannot say the same. The password hashing
    > > > > system being changed in the past year, poor stability and machine lockups are
    > > > > what I have noticed, besides there is nothing like the readme here:
    > > >
    > > > cryptoloop is also unusably slow, even on my x86_64 machines...
    > >
    > > I'm obviously doing something wrong, I just copied about 40MB of old
    > > kernels (vmlinuz*) and some jpg files into a subdir on my cryptoloop
    > > filesystem, and I measured 4252.2375kB/s realtime and 18819.7879 kB/s CPU
    > > time. This doesn't seem unusably slow, even on my mighty P-II/350 and
    > > eight year old 4GB drives. The hdb is so old it has to run in pio mode, to
    > > give you an idea, and the original data was not in memory.
    >
    > I've rewritten some CBC code to fit the facilities I introduce in my LRW
    > patch[1]. Here are the results for my P4@1.8GHZ:
    >
    > loop-aes, CBC: ~30.5mb/s
    > dm-crypt, CBC prior to my rewrite: ~23mb/s
    > dm-crypt, CBC with my LRW patch: ~27mb/s
    > dm-crypt, LRW with my LRW patch: ~27mb/s (slightly faster than CBC)
    >
    > As you can see my LRW patches (actually it's the generic scatterwalker
    > which is part of the LRW patch set) halves the gap to loop-aes.

    Actually I was using the built-in cryptoloop, not aes, I was just noting
    that on a really slow CPU it's still usefully fast in my estimation.

    >
    > I'm sure dm-crypt is never going to achieve the speed of loop-aes.
    > That's just the price you pay, when you have to do things right and
    > clean, so they get merged into main. Kernel developers are choosey
    > customers, you know.

    Yes, I delighted that cryptoloop is in the kernel. The dm-crypt is an
    interesting method suitable for technically adept users who do all their
    own sysadmin and need better crypto to protect something very valuable or
    illegal.

    But for a company trying to protect information on laptops from casual
    laptop theves, the existing cryptoloop is fine, and the greater complexity
    of dm-crypt isn't cost effective. Speed isn't an issue, ease of use and
    avoiding training costs is.

    >
    > [1] http://clemens.endorphin.org/patches/lrw/
    >
    > --
    > Fruhwirth Clemens <clemens@endorphin.org> http://clemens.endorphin.org
    >

    -- 
    bill davidsen <davidsen@tmr.com>
      CTO, TMR Associates, Inc
    Doing interesting things with little computers since 1979.
    
    

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