id: 06019478 dt: j an: 06019478 au: Koblitz, Neal; Menezes, Alfred; Shparlinski, Igor E. ti: Discrete logarithms, Diffie-Hellman, and reductions. so: Vietnam J. Math. 39, No. 3, 267-285 (2011). py: 2011 pu: Vietnamese Academy of Science and Technology, Hanoi; Vietnam Mathematical Society, Hanoi la: EN cc: ut: ci: li: ab: Summary: We consider the One-Prime-Not-$p$ and All-Primes-But-$p$ variants of the Discrete Logarithm (DL) problem in a group of prime order $p$. We give reductions to the Diffie-Hellman (DH) problem that do not depend on any unproved conjectures about smooth or prime numbers in short intervals. We show that the One-Prime-Not-$p$-DL problem reduces to DH in time roughly $L_p(1/2)$; the All-Primes-But-$p$-DL problem $p$ reduces to DH in time roughly $L_p (2/5)$; and the All-Primes-But-$p$-DL problem reduces $p$ to the DH plus Integer Factorization problems in polynomial time. We also prove that under the Riemann Hypothesis, with $ε\log p$ queries to a yes-or-no oracle one can reduce DL to DH in time roughly $L_p (1/2)$; and under a conjecture about smooth numbers, $p$ with $ε\log p$ queries to a yes-or-no oracle one can reduce DL to DH in polynomial time. rv: