How broad is the SPEKE patent.

Steven M. Bellovin smb at
Wed Nov 9 07:54:53 PST 2005

In message <43713115.4942.4A3995E at localhost>, "James A. Donald" writes:
>    --
>Does SPEKE claim to patent any uses of zero knowledge
>proof of possession of the password for mutual
>authentication, or just some particular method for
>establishing communications?   Is there any way around
>the SPEKE patent for mutual authentication and
>establishing secure communications on a weak passphrase? 

It certainly doesn't claim EKE, by myself and Michael Merritt, since he 
and I invented the field.  Of course, EKE is also patented.  

SRP is patented but royalty-free.  Some of have claimed that it 
infringes the EKE patent; since I don't work for the EKE patent owner 
(Lucent), I've never tried to verify that.

Radia Perlman and Charlie Kaufman invented PDM specifically as a 
patent-free method.  However, the claim was made that it infringed the 
SPEKE patent.  Since it wasn't patented, there was no one willing to 
spend the money on legal fees to fight that claim, per a story I heard.

Have a look at
for some history.

		--Steven M. Bellovin,

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