Optimal Security for Keyed Hash Functions: Avoiding Time-Space Tradeoffs for Finding Collisions

ePrint Report: Optimal Security for Keyed Hash Functions: Avoiding Time-Space Tradeoffs for Finding Collisions

Cody Freitag, Ashrujit Ghoshal, Ilan Komargodski

Cryptographic hash functions map data of arbitrary size to a fixed size digest, and are one of the most commonly used cryptographic objects. As it is infeasible to design an individual hash function for every input size, variable-input length hash functions are built by designing and bootstrapping a single fixed-input length function that looks sufficiently random. To prevent trivial preprocessing …

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