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

["Wook Shin" <[e-mail]>]

> Personal opinion.  It will be easier and clearer if you go back to using  
> circular shift operations.

I agree. I will go with the circular shift notations in the next
version of the draft.

Wook


On Thu, 14 Apr 2011 09:47:54 +0900, Jim Schaad <[e-mail]>  
wrote:

> Personal opinion.  It will be easier and clearer if you go back to using  
> circular shift operations.
>
> Jim
>
>
>> -----Original Message-----
>> From: Wook Shin [mailto:[e-mail]]
>> Sent: Wednesday, April 13, 2011 1:31 AM
>> To: [e-mail]; Jim Schaad
>> Subject: Re: I-D Action:draft-kiyomoto-kcipher2-02.txt
>>
>> Jim,
>>
>> That's my mistake. I think I made that mistake while converting  
>> circular shift
>> operations to the combination of XOR and non-circular shit operations.
>>
>> The notation in Section 2.1 should be corrected to
>>
>>    <<n t     t-bit left shift in an n-bit register
>>    >>n t     t-bit right shift in an n-bit register
>>
>> and then, the code
>>
>>    SubK2((IK[3] <<32 8) XOR (IK[3] >>32 24))
>>      XOR (0x01, 0x00, 0x00, 0x00);
>>
>> should mean that
>>
>>   (1) IK[3] gets left-shifted by 8 bits
>>   (2) IK[3] gets right-shifted by 24 bits
>>   (3) call SubK2() by giving "(1) XOR (2) XOR 0x01000000"
>>       as the input parameter
>>
>> Best regards,
>>
>> Wook
>>
>>
>>
>>
>> On Wed, 13 Apr 2011 17:23:10 +0900, Jim Schaad <[e-mail]>
>> wrote:
>>
>> > 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:[e-mail]]
>> >> Sent: Tuesday, April 12, 2011 6:39 PM
>> >> To: [e-mail]
>> >> 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
>>
>>
>> --
>> Wook Shin
>> Information Security Laboratory,
>> KDDI R&D Laboratories, Inc.


-- 
Wook Shin
Information Security Laboratory,
KDDI R&D Laboratories, Inc.