Decisional second-preimage resistance: when does SPR imply PRE?

Research output: Other contributionAcademic


There is a well-known gap between second-preimage resistance and preimage resistance for length-preserving hash functions. This paper introduces a simple concept that fills this gap. One consequence of this concept is that tight reductions can remove interactivity for multi-target length-preserving preimage problems, such as the problems that appear in analyzing hash-based signature systems. Previous reduction techniques applied to only a negligible fraction of all length-preserving hash functions, presumably excluding all off-the-shelf hash functions.
Original languageEnglish
Number of pages36
Publication statusPublished - 2019


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