From: Milan Broz <mbroz@redhat.com>
To: Sebastian Andrzej Siewior <linux-crypto@ml.breakpoint.cc>
Cc: Mikulas Patocka <mpatocka@redhat.com>,
dm-devel@redhat.com, Alasdair G Kergon <agk@redhat.com>,
linux-crypto@vger.kernel.org
Subject: Re: [PATCH] dm-crypt: disable block encryption with arc4
Date: Tue, 26 Jan 2010 11:48:55 +0100 [thread overview]
Message-ID: <4B5EC897.5050102@redhat.com> (raw)
In-Reply-To: <20100126092234.GA3304@Chamillionaire.breakpoint.cc>
On 01/26/2010 10:22 AM, Sebastian Andrzej Siewior wrote:
> * Milan Broz | 2010-01-25 19:39:11 [+0100]:
>> On 01/25/2010 07:29 PM, Mikulas Patocka wrote:
>>> 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
>
> I some how remember Herbert saying to test for block size > 1. Wouldn't
> this be acceptable to block all stream cipher in one go?
yes, I think it is better.
(...and I just forgot to add that test to dm-crypt after that suggestion.)
Milan
next prev parent reply other threads:[~2010-01-26 10:49 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-25 18:29 [PATCH] dm-crypt: disable block encryption with arc4 Mikulas Patocka
2010-01-25 18:39 ` Milan Broz
2010-01-26 9:22 ` Sebastian Andrzej Siewior
2010-01-26 10:48 ` Milan Broz [this message]
2010-01-26 12:27 ` Mikulas Patocka
2010-01-26 13:34 ` Sebastian Andrzej Siewior
2010-01-26 17:11 ` Mikulas Patocka
2010-02-09 7:37 ` Herbert Xu
2010-02-09 14:02 ` Mikulas Patocka
2010-02-09 20:42 ` Herbert Xu
2010-02-09 14:57 ` Sebastian Andrzej Siewior
2010-02-09 20:45 ` Herbert Xu
2010-02-09 21:12 ` Sebastian Andrzej Siewior
2010-02-09 21:45 ` Herbert Xu
2010-02-12 8:42 ` [PATCH] crypto/arc4: convert this stream cipher into a block cipher Sebastian Andrzej Siewior
2010-02-12 9:34 ` Adrian-Ken Rueegsegger
2010-02-12 9:57 ` Sebastian Andrzej Siewior
2010-02-14 20:42 ` Sebastian Andrzej Siewior
2010-02-15 0:10 ` Herbert Xu
2010-02-15 8:49 ` Sebastian Andrzej Siewior
2010-02-16 12:51 ` Herbert Xu
2010-02-21 20:01 ` Sebastian Andrzej Siewior
2010-02-22 0:45 ` Herbert Xu
2010-02-22 0:52 ` Herbert Xu
2010-02-22 22:08 ` Sebastian Andrzej Siewior
2010-02-23 0:32 ` Herbert Xu
2010-03-14 8:24 ` Sebastian Andrzej Siewior
2010-03-14 9:06 ` Herbert Xu
[not found] ` <Pine.LNX.4.64.1002221400090.31819@hs20-bc2-1.build.redhat.com>
2010-02-23 0:15 ` Herbert Xu
2010-01-26 12:59 ` [dm-devel] [PATCH] dm-crypt: disable block encryption with arc4 Alasdair G Kergon
2010-01-25 18:39 ` Mikulas Patocka
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