zero-knowledge proof of equality of discrete log

From: Hannes Zodde (
Date: 08/04/05

Date: Thu, 04 Aug 2005 17:45:47 +0200

Hi group,

I know there is a honest-verifier zero-knoweldge proof for proving that
the discrete logarithm of 2 numbers a,b is equal (e.g. the proof of
Chaum & Pedersen). I wonder now, whether there is a proof for that
problem, to prove the fact in "real" zero-knowledge? Is such possible?
Is it efficient? Can you point me to some papers?

Thanks for your help,