Security of Blind Discrete Log Signatures against Interactive Attacks

摘要: We present a novel parallel one-more signature forgery against blind Okamoto-Schnorr and Schnorr signatures in which an attacker interacts some l times with legitimate signer produces from these interactions + 1 signatures. Security the new attack requires that following ROS-problem is intractable: find overdetermined, solvable system of linear equations modulo q random inhomogenities (right sides).There inherent weakness security result POINTCHEVAL AND STERN. Theorem 26[PS00] does not cover attacks 4 for elliptic curves order 2200. That would require intractability ROS-problem, plausible but complexity assumption. Conversely, assuming we show are secure oracle generic group model forgery.