Journal of Mathematical Cryptology (Aug 2020)

New Zémor-Tillich Type Hash Functions Over GL2 (𝔽pn)

  • Tomkins Hayley,
  • Nevins Monica,
  • Salmasian Hadi

DOI
https://doi.org/10.1515/jmc-2019-0033
Journal volume & issue
Vol. 14, no. 1
pp. 236 – 253

Abstract

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We present a large class of new Zémor-Tillich type hash functions whose target space is the finite group GL2(𝔽pn) for any prime p and power n. To do so, we use a novel group-theoretic approach that uses Tits’ “Ping-Pong Lemma” to outline conditions under which a set of matrices in PGL2(𝔽p((x))) generates a free group. The hash functions we form are secure against known attacks, and simultaneously preserve many of the desired features of the Zémor-Tillich hash function. In particular, our hash functions retain the mall modifications property.

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