The universality of iterated hashing over variable-length strings

  • Authors:
  • Daniel Lemire

  • Affiliations:
  • -

  • Venue:
  • Discrete Applied Mathematics
  • Year:
  • 2012

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Abstract

Iterated hash functions process strings recursively, one character at a time. At each iteration, they compute a new hash value from the preceding hash value and the next character. We prove that iterated hashing can be pairwise independent, but never 3-wise independent. We show that it can be almost universal over strings much longer than the number of hash values; we bound the maximal string length given the collision probability.