Paper 2016/312 Original: eprint.iacr.org/2016/312 ↗

Refinements of the k-tree Algorithm for the Generalized Birthday Problem

Ivica Nikolic
Yu Sasaki
Abstract

We study two open problems proposed by Wagner in his seminal work on the generalized birthday problem. First, with the use of multicollisions, we improve Wagner's $3$-tree algorithm. The new 3-tree only slightly outperforms Wagner's 3-tree, however, in some applications this suffices, and as a proof of concept, we apply the new algorithm to slightly reduce the security of two CAESAR proposals. Next, with the use of multiple collisions based on Hellman's table, we give improvements to the best known time-memory tradeoffs for the k-tree. As a result, we obtain the a new tradeoff curve T^2 \cdot M^{\lg k -1} = k \cdot N. For instance, when k=4, the tradeoff has the form T^2 M = 4 \cdot N.

Metadata
Available format(s)
PDF
Category
Secret-key cryptography
Publication info
Preprint.
History
2016-03-21: last updated
2016-03-21: published
Short URL
https://ia.cr/2016/312
License
https://creativecommons.org/licenses/by/4.0/

BibTeX

@misc{cryptoeprint:2016/312,
      author = {Ivica Nikolic and Yu Sasaki},
      title = {Refinements of the k-tree Algorithm for the Generalized Birthday Problem},
      howpublished = {Cryptology {ePrint} Archive, Paper 2016/312},
      year = {2016},
      url = {https://eprint.iacr.org/2016/312}
}
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