Re: GELI - disk encryption for FreeBSD - review request.

From: Andrew Swallow (am.swallow_at_btopenworld.com)
Date: 07/29/05 

Date: Fri, 29 Jul 2005 18:54:25 +0000 (UTC)

Joseph Ashwood wrote:

> "Andrew Swallow" <am.swallow@btopenworld.com> wrote in message
> news:dcc4na$7p1$1@nwrdmz03.dmz.ncs.ea.ibs-infra.bt.com...
>
>>Joseph Ashwood wrote:
>
> [use entropy collection]
>
>>Entropy collection quickly runs into practical problems.
>>For a disk being written to 50 times a second
>>50 * 24 = 1200 bits of entropy per second.
>>
>>Servers frequently do not even have a mouse to wave around.
>>There may be sufficient entropy to change the second key
>>variable every time you power up.
>
>
> That could pose a problem. I'm not entirely certain of the real
> requirements, I haven't given those much investigation, for examination I
> had simply assumed an infinite number of purely entropic bits were easily
> available. I'm sure there's some compromise between pure entropy and CTR
> mode that will be secure.
> Joe

My view is that if you are designing a disk control
board/chip with built in encryption include the small
number of analogue components to make a random number
generator.

Andrew Swallow

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