On Wednesday 27 July 2005 13:18, Pasztor Andras wrote:
> But if I don't allow the reusing of the "nonce" then we don't need qop.
> Am I right?

Yes principally that is right. But then you also do not need nextnonce (your 
original question).
I fear there are implementations which re-use the nonce without using qop. In 
this case nextnonce would a nice hint for all attackers. Simply avoid that by 
using qop always if it is supported.

  Nils

> br
> Andras
>
> Nils Ohlmeier <[EMAIL PROTECTED]> írta:
> > Hi,
> >
> > On Thursday 21 July 2005 18:55, The Rev wrote:
> > > Is there somebody who knows what is the effect on the
>
> overall security of
>
> > > SIP sessions if we send the "nextnonce" in the Auth-Info
>
> of 200OK of
>
> > > Register or INVITE.
> > >
> > > I'm a little bit afraid to implement because I may open
>
> a security hole
>
> > > towards hackers since the hacker has e.g 60 min time to
>
> calculate a
>
> > > response. I'm not a security expert unfortunately:-(
> >
> > if you do not use qop, which you should, it tells the
>
> eavesdropper how long
>
> > he can use the last reply for replay attacks. If you use
>
> qop it should not
>
> > matter.
> >
> > Regards
> >   Nils Ohlmeier
> > --
> > gpg-key: http://www.ohlmeier.org/public_key.asc
> > _______________________________________________
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>
> implementors
>
>
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