Interactive and Noninteractive
Zero Knowledge
Are Equivalent in the Help Model
André Chailloux, Iordanis Kerenidis, Dragos Florin Ciocan, Salil Vadhan
We
show that interactive and noninteractive zero-knowledge are equivalent in the
“help model” of Ben-Or and Gutfreund (J. Cryptology, 2003). In this model, the shared reference string is
generated by a probabilistic polynomial-time dealer who is given access to the
statement to be proven. Our results do not rely on any unproven complexity
assumptions and hold for statistical zero knowledge, for computational zero
knowledge restricted to AM, and for quantum zero knowledge when the help is a
pure quantum state.