Paper 2015/1148

An Inverse-free Single-Keyed Tweakable Enciphering Scheme

Ritam Bhaumik and Mridul Nandi

Abstract

In CRYPTO 2003, Halevi and Rogaway proposed CMC, a tweakable enciphering scheme (TES) based on a blockcipher. It requires two blockcipher keys and it is not inverse-free (i.e., the decryption algorithm uses the inverse (decryption) of the underlying blockcipher). We present here a new inverse-free, single-keyed TES. Our construction is a tweakable strong pseudorandom permutation (tsprp), i.e., it is secure against chosen-plaintext-ciphertext adversaries assuming that the underlying blockcipher is a pseudorandom permutation (prp), i.e., secure against chosen-plaintext adversaries. In comparison, sprp assumption of the blockcipher is required for the sprp security of CMC. Our scheme can be viewed as a mixture of type-1 and type-3 Feistel cipher and so we call it FMix or mixed-type Feistel cipher.

Metadata
Available format(s)
PDF
Category
Secret-key cryptography
Publication info
Published by the IACR in ASIACRYPT 2015
Keywords
(Tweakable Strong) pseudorandom permutationCoefficient H TechniqueEncipherCMCFeistel Cipher.
Contact author(s)
bhaumik ritam @ gmail com
History
2015-11-27: received
Short URL
https://ia.cr/2015/1148
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2015/1148,
      author = {Ritam Bhaumik and Mridul Nandi},
      title = {An Inverse-free Single-Keyed Tweakable Enciphering Scheme},
      howpublished = {Cryptology {ePrint} Archive, Paper 2015/1148},
      year = {2015},
      url = {https://eprint.iacr.org/2015/1148}
}
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