On the equivalence of authentication codes and robust (2,2)-threshold schemes
This work addresses foundational problems in cryptography for researchers, offering incremental insights into the relationships between authentication and secret sharing.
The paper establishes a direct equivalence between certain authentication codes and robust secret sharing schemes, which was not previously considered, and introduces a key-substitution attack to analyze dual authentication codes, providing proofs and generalizations for known constructions.
In this paper, we show a "direct" equivalence between certain authentication codes and robust secret sharing schemes. It was previously known that authentication codes and robust secret sharing schemes are closely related to similar types of designs, but direct equivalences had not been considered in the literature. Our new equivalences motivate the consideration of a certain "key-substitution attack." We study this attack and analyze it in the setting of "dual authentication codes." We also show how this viewpoint provides a nice way to prove properties and generalizations of some known constructions.