[dm-devel] [PATCH] dm-crypt: disable block encryption with arc4

Milan Broz mbroz at redhat.com
Mon Jan 25 18:39:11 UTC 2010


On 01/25/2010 07:29 PM, Mikulas Patocka wrote:
> Hi
> 
> When using arc4 to encrypt a block device, the resulting device is 
> unreliable. It reads garbage. That's because arc4 is a stream cipher, if 
> you write something, it advances its state and if you attempt to decrypt 
> the same sector, it uses new state that is different.
> 
> This patch disables the use of arc4 on block devices.

arc4 again. it is simply not a block cipher:-)

This should be solved inside cryptoAPI and not blacklist it in dm-crypt,
see that thread
http://article.gmane.org/gmane.linux.kernel.cryptoapi/3441

Milan




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