Reducing complexity assumptions for statistically-hiding commitment

TitleReducing complexity assumptions for statistically-hiding commitment
Publication TypeConference Papers
Year of Publication2004
AuthorsHorvitz O, Katz J, Koo CY, Morselli R
Conference NameIn EUROCRYPT
Date Published2004///

Determining the minimal assumptions needed to construct various cryptographic buildingblocks has been a focal point of research in theoretical cryptography. For most — but not
all! — cryptographic primitives, complexity assumptions both necessary and sufficient for their
existence are known. Here, we revisit the following, decade-old question: what are the minimal
assumptions needed to construct a statistically-hiding bit commitment scheme? Previously, it
was known how to construct such schemes based on any one-way permutation. In this work, we
show that regular one-way functions suffice.
We show two constructions of statistically-hiding commitment schemes from regular one-way
functions. Our first construction is more direct, and serves as a “stepping-stone” for our second
construction which has improved round complexity. Of independent interest, as part of our work
we show a compiler transforming any commitment scheme which is statistically-hiding against
an honest-but-curious receiver to one which is statistically-hiding against a malicious receiver.
This demonstrates the equivalence of these two formulations of the problem.