Qquestions that i can not understand!!!

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Qquestions that i can not understand!!!

Post  Daystar on Tue Apr 26, 2011 6:50 pm

in the BR ,why do we choose bits from s0,s2,s5,s7,s9,s11,s14,s15 other than others ???
what is the reason of this choice??
When we set values of LFSR states,why we choose D like:
d0=100010011010111
d1=010011010111100
d2=110001001101011
......
what if we choose other values?????

Daystar
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Who can answer me in detail !

Post  Daystar on Wed Apr 27, 2011 5:50 am

Who can answer me in detail !

Daystar
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Re: Qquestions that i can not understand!!!

Post  Xiutao Feng on Mon May 23, 2011 9:24 pm

Pls. refer to the criteria on the design of the bit reorganization below:
1. Suitable for software implementation;
2. The four 32-bit words from the bit reorganization have good randomness in the statistical sense;
3. The number of the overlapping bits of four 32-bit words at consecutive times is small.

As for the constant D, it is constructed by some m-sequences of length 15, see:
http://zucalg.forumotion.net/t32-the-source-for-the-constant-d

Xiutao Feng

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Re: Qquestions that i can not understand!!!

Post  Xiutao Feng on Mon May 23, 2011 9:28 pm

Of course, you can choose other values to the constant D. I believe that they have no essential effect to ZUC's security.

Daystar wrote:in the BR ,why do we choose bits from s0,s2,s5,s7,s9,s11,s14,s15 other than others ???
what is the reason of this choice??
When we set values of LFSR states,why we choose D like:
d0=100010011010111
d1=010011010111100
d2=110001001101011
......
what if we choose other values?????

Xiutao Feng

Posts : 13
Join date : 2010-08-20

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Re: Qquestions that i can not understand!!!

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