Re: [P1363:] HIBE Scheme

[Nigel Smart <nigel@xxxxxxxxxxxxx>]

Hi

I agree with Hovav on this one.

Can you name an environment where GS is better? That is assuming
the implementor chooses correct security parameters and the most
modern and efficient pairing parameters for that setting. i.e.
some real values for all the parameters, choices of pairings
and hash-to-point functions.

Nigel

kobayashi.tetsutaro wrote:
> > > I agree that we should add one pairing to the efficiency of GS-HIBE  
> > > that
> > > I stated.  However, GS-HIBE is as efficient as BBG/BB-HIBE, and is not
> > > worse when t is small.
> > No, it's not; it's less efficient, even for t=1.
>
> My claim is that GS-HIBE is more efficient under some environments.  For
> example, BBG-HIBE scheme requires more number of pairings than GS-HIBE
> in decryption when t is small.  If the smaller number of pairings in
> decryption is the dominant factor of the efficiency of a system, then
> GS-HIBE is more efficient.  All we can say is that BB/BBG-HIBE can be
> more efficient than GS-HIBE under some environments, as well as GS-HIBE
> can be under others.
>
> I think there is no significant flaw in the GS-HIBE scheme that makes us
> exclude it from this working draft.
>
>
> > On May 27, 2009, at 2:11 AM, kobayashi.tetsutaro wrote:
> >
> > > Please notice that I am just proposing an HIBE schme, and not making
> > > objection to proposing BBG/BB-HIBE.
> > Well, I am, to GS; unless there's a legacy need to standardize GS --  
> > that is, if someone is actually using it -- then I believe it should  
> > not be offered as an option.
> >
> > > I agree that we should add one pairing to the efficiency of GS-HIBE  
> > > that
> > > I stated.  However, GS-HIBE is as efficient as BBG/BB-HIBE, and is not
> > > worse when t is small.
> > No, it's not; it's less efficient, even for t=1.
> >
> > -hs.

--
Prof. Nigel P. Smart               | Phone: +44 (0)117 954 5163
Computer Science Department,       | Fax:   +44 (0)117 954 5208
Woodland Road,                     | Email: nigel@xxxxxxxxxxxxx
University of Bristol, BS8 1UB, UK | URL:   http://www.cs.bris.ac.uk/~nigel/

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