A Combinatorial Analysis of HC-128

Goutam Paul; Subhamoy Maitra; Shashwat Raizada

Paper 2010/387

A Combinatorial Analysis of HC-128

Goutam Paul, Subhamoy Maitra, and Shashwat Raizada

Abstract

We show that the knowledge of any one of the two internal state arrays of HC-128 along with the knowledge of 2048 keystream words is sufficient to construct the other state array completely in $2^{42}$ time complexity. Though our analysis does not lead to any attack on HC-128, it reveals a structural insight into the cipher. In the process, we theoretically establish certain combinatorial properties of HC-128 keystream generation algorithm. We also suggest a modification to HC-128 that takes care of the recently known cryptanalytic results with little reduction in speed.

Note: Publication information added.

Metadata

Available format(s): PDF
Category: Secret-key cryptography
Publication info: Published elsewhere. IWSEC 2011 (title: "A Theoretical Analysis of the Structure of HC-128")
Keywords: Cryptography eSTREAM HC-128 Keystream State Recovery Stream Cipher.
Contact author(s): subho @ isical ac in
History: 2011-11-16: last of 2 revisions; 2010-07-09: received; See all versions
Short URL: https://ia.cr/2010/387
License: CC BY

BibTeX

@misc{cryptoeprint:2010/387,
      author = {Goutam Paul and Subhamoy Maitra and Shashwat Raizada},
      title = {A Combinatorial Analysis of HC-128},
      howpublished = {Cryptology ePrint Archive, Paper 2010/387},
      year = {2010},
      note = {\url{https://eprint.iacr.org/2010/387}},
      url = {https://eprint.iacr.org/2010/387}
}