Re: OMAC help

From: unknown (unknown_at_unknown.com)
Date: 06/14/03 

Date: Sat, 14 Jun 2003 16:50:27 +0100

> > there is OMAC1 and OMAC2 - where OMAC2 (the original spec) uses a
> > E_k(0) * u^-1 as one of the keys, OMAC1 uses E_k(0) * u^2 instead.
I have
> > found OMAC1 to be significantly more convenient to implement.
Though
> > which one NIST will standardize is pretty much up in the air -
when I
> > asked Morris Dworkin, all he would say is "we generally defer to
the
> > algorithm designers in such matters"

Hi all,

    I'm having some problems in understanding how to deal with
polynomial multiplication, so I would be very grateful if you could
help me.

    In the EAX paper it is defined that B=2L and P=2(2L). I can
understan this, however, in the EMD paper, it is defined that some
value (hereinafter designated by Xi) is defined by Xi=iL for i=1..n
(the polynomial X is the same). How can this be calculated for i other
than 2 and 4?

    Could you please represent, in pseudo-code, a function to
calculate the values from i=1 to i=n ?

    Thanks in advance.

    Best regards,

    unknown

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