From: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Subject: Re: [PATCH v2] crypto: add blkcipher implementation of ARC4
Date: Wed, 7 Apr 2010 10:23:00 +0200
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To: Herbert Xu <herbert@gondor.apana.org.au>
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* Herbert Xu | 2010-04-07 08:31:09 [+0800]:

>On Tue, Apr 06, 2010 at 10:30:02PM +0200, Sebastian Andrzej Siewior wrote:
>>
>> Good point. All arc4 users don't care about return value of setkey so I
>> think that I just change void to int add the check for the valid key
>> length.
>
>Actually, how about getting arc4_setup_iv to do all the legwork
>and turn it into a real IV? Then we don't need any checks on the
>data path.
So arc4_setup_iv() should do what the internal arc4_ivsetup() does and
we change void to int and check the keysize in there right? The problem
here is that we are bounded to *this* implementation of the algorithm
and are not able to replace it with a different implementation. Not that
this is likely to happen for RC4 but it may be true for other stream
ciphers.

>> While we are here, the .setkey() callback could be removed, couldn't it?
>> It returns 0 even it is doing nothing what looks kinda wrong. However it
>> shouldn't be called at all since min/max key is 0. Any objections on
>> that?
>
>I'm pretty sure testmgr will call setkey even for keylen == 0, no?
Prior patch #3 it has no test case so it should not test it at all.
Patch #3 adds a flag in order to distinguish it. You want to look at
patch #3 now :)

>
>Thanks,

Sebastian