Improved lower bound for Diffie–Hellman problem using multiplicative group of a finite field as auxiliary group

• Main Author: Kushwaha Prabhat
• Format: Article
• Language: English
• Published: De Gruyter 2018-06-01
• Series: Journal of Mathematical Cryptology
• Subjects: discrete logarithm problem; lower bound for the diffie–hellman problem; elliptic curves used in practical applications; 94a60
• Online Access: https://doi.org/10.1515/jmc-2017-0053

In 2004, Muzereau, Smart and Vercauteren [A. Muzereau, N. P. Smart and F. Vercauteren, The equivalence between the DHP and DLP for elliptic curves used in practical applications, LMS J. Comput. Math. 7 2004, 50–72] showed how to use a reduction algorithm of the discrete logarithm problem to Diffie–Hellman problem in order to estimate lower bound for the Diffie–Hellman problem on elliptic curves. They presented their estimates on various elliptic curves that are used in practical applications. In this paper, we show that a much tighter lower bound for the Diffie–Hellman problem on those curves can be achieved if one uses the multiplicative group of a finite field as auxiliary group. The improved lower bound estimates of the Diffie–Hellman problem on those recommended curves are also presented. Moreover, we have also extended our idea by presenting similar estimates of DHP on some more recommended curves which were not covered before. These estimates of DHP on these curves are currently the tightest which lead us towards the equivalence of the Diffie–Hellman problem and the discrete logarithm problem on these recommended elliptic curves.