Re: [Cfrg] I-D Action:draft-kiyomoto-kcipher2-02.txt

"Jim Schaad" <ietf@augustcellars.com> Wed, 13 April 2011 07:57 UTC

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From: "Jim Schaad" <ietf@augustcellars.com>
To: "'Wook Shin'" <wookshin@kddilabs.jp>, <cfrg@irtf.org>
References: <20110413010001.17531.11616.idtracker@ietfc.amsl.com> <op.vtur72zepzjggh@ohpato-t61.sec.kddilabs.jp>
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Date: Wed, 13 Apr 2011 01:23:10 -0700
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Subject: Re: [Cfrg] I-D Action:draft-kiyomoto-kcipher2-02.txt
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You have a notation that is leaving me puzzled.

In section 2.1 you say

     <<n   Left circular rotation by n bits

      >>n   Right circular rotation by n bits

Which makes sense.

However in section 2.3.2 you use the notation

           SubK2((IK[3] <<32 8) XOR (IK[3] >>32 24)) XOR
            (0x01, 0x00, 0x00, 0x00);

Which is not covered by the above.  

Additionally I wonder if you mean to use IK[3] in both locations here as (I think)

(IK[3] << 8) XOR (IK[3] >> 24) ---> (IK[3] << 8) XOR (IK[3] << (32-24)) --> (IK[3] << 8) XOR (IK[3] << 8)

jim

> -----Original Message-----
> From: Wook Shin [mailto:wookshin@kddilabs.jp]
> Sent: Tuesday, April 12, 2011 6:39 PM
> To: cfrg@irtf.org
> Subject: Re: I-D Action:draft-kiyomoto-kcipher2-02.txt
> 
> Hello all,
> 
> I've revised our previous draft that explains the KCipher-2 stream cipher.
> The current version includes some code snippets written in the C language
> syntax, so that it could help implementers get clearer idea of how it works
> and help them check their outputs with the test vectors mentioned in the
> draft.
> The new version of the draft can be found at
>    http://www.ietf.org/internet-drafts/draft-kiyomoto-kcipher2-02.txt
> 
> I have attached a naive implementation of KCipher-2 written in C.
> Two files, KCipher2.c and KCipher2.h, are in the attached .zip file, and no
> special option is required to compile and run the program.
> The code snippets and the test vector running examples in the draft are
> from the the attached code.
> 
> Please look at the new version of the draft and the code, and let me have
> your comments.
> 
> Thank you,
> 
> Wook