Paper 2012/009

On the Indifferentiability of the Integrated-Key Hash Functions

Saif Al-Kuwari


Most of today's popular hash functions are keyless such that they accept variable-length messages and return fixed-length fingerprints. However, recent separation results reported on several serious inherent weaknesses in these functions, motivating the design of hash functions in the keyed setting. The challenge in this case, however, is that on one hand, it is economically undesirable to abundant the already adopted (keyless) functions in favour of new (keyed) ones, and on the other hand, the process of converting a keyless function to a keyed one is, evidently, non-trivial. A solution to this dilemma is to adopt the "integrated-key" approach that creates keyed hash functions out of "unmodified" keyless primitives. In this paper, we adopt several integrated-key constructions and prove that they are indifferentiable from random oracle, showing in details how to develop indifferentiability proofs at the integrated-key setting. The presented indifferentiability proof is generic and can be applied on other hash functions constructed in this setting with sufficiently similar structures to the constructions in this paper.

Available format(s)
Publication info
Published elsewhere. Unknown where it was published
Hash FunctionsIndifferentiabilityROIntegrated-Key
Contact author(s)
s alkuwari @ bath edu
2012-01-07: received
Short URL
Creative Commons Attribution


      author = {Saif Al-Kuwari},
      title = {On the Indifferentiability of the Integrated-Key Hash Functions},
      howpublished = {Cryptology ePrint Archive, Paper 2012/009},
      year = {2012},
      note = {\url{}},
      url = {}
Note: In order to protect the privacy of readers, does not use cookies or embedded third party content.