Re: AES-CBC + Elephant diffuser

2009-11-01 Thread Darren J Moffat

Eugen Leitl wrote:

We discuss why no existing cipher satisfies the requirements of this
application. Uh-oh.

http://www.microsoft.com/downloads/details.aspx?FamilyID=131dae03-39ae-48be-a8d6-8b0034c92555DisplayLang=en

AES-CBC + Elephant diffuser

Brief Description

A Disk Encryption Algorithm for Windows Vista

^^^

That is the key issue here, it is a disk encryption algorithm 
independent of the filesystem that sits above it.


If instead you put the encryption directly into the filesystem, rather 
than below it, then the restrictions of sector size that mean you can't 
easily use a MAC go away.


This is exactly what we have done for ZFS, we do use a MAC (the one from 
CCM or GCM modes) as well as a SHA256 hash of the ciphertext (used for 
resilvering operations in RAID) and they are stored in the block 
pointers (not the data blocks) forming a Merkle tree.  We also have a 
place to store an IV.  So every encrypted ZFS block is self contained, 
has an IV and a 16 byte MAC.   This means that the crypto is all 
standards based algorithms and modes for ZFS.


http://hub.opensolaris.org/bin/view/Project+zfs-crypto/

--
Darren J Moffat

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Re: AES-CBC + Elephant diffuser

2009-11-01 Thread Paul Hoffman
At 2:24 PM +0100 10/29/09, Eugen Leitl wrote:
We discuss why no existing cipher satisfies the requirements of this
application. Uh-oh.

Yeah, we all know what a light-weight and careless person Neils Ferguson is. 
Who would listen to him?

--Paul Hoffman, Director
--VPN Consortium

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Re: AES-CBC + Elephant diffuser

2009-11-01 Thread Eugen Leitl
On Thu, Oct 29, 2009 at 07:15:53AM -0700, Paul Hoffman wrote:
 At 2:24 PM +0100 10/29/09, Eugen Leitl wrote:
 We discuss why no existing cipher satisfies the requirements of this
 application. Uh-oh.
 
 Yeah, we all know what a light-weight and careless person Neils Ferguson is. 
 Who would listen to him?

Ah, should have spent a few seconds looking him up
http://en.wikipedia.org/wiki/Niels_Ferguson
http://www.macfergus.com/

-- 
Eugen* Leitl a href=http://leitl.org;leitl/a http://leitl.org
__
ICBM: 48.07100, 11.36820 http://www.ativel.com http://postbiota.org
8B29F6BE: 099D 78BA 2FD3 B014 B08A  7779 75B0 2443 8B29 F6BE

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