Cryptanalysis Categories

From The ECRYPT Hash Function Website
Revision as of 09:14, 24 December 2008 by Mschlaeffer (talk | contribs)

For presentation reasons, we provide a *simplified* overview of cryptanalytic results in The SHA-3 Zoo. We only consider cryptanalytic results that have not been performed by the designers themselves and are included in the initial proposal. Exceptions are cryptanalytic results by non-designers and cryptanalytic results by designers that are not mentioned in the proposal.

1 Color Codes

Different color codes should give a better overview of the impact of cryptanalytic results. The color codes are only used for results on the main NIST requirements of the full hash function with recommended parameters.

color Complexity of Result Explanation
compr. calls < generic The number of compression function calls (or equivalents) is below generic attacks for collision, 2nd preimage or preimage. The complexity of the attack is very close to generic attacks and is therefore of lesser relevance.
compr. calls < generic * 1/n The number of compression function calls is below generic attacks reduced by a factor of n (hash size) for collision, 2nd preimage or preimage. Attacks in this simple model neglect memory considerations. However, attacks of this type to not exist for the SHA-2 hash functions.
time*memory < generic The time*memory product is below generic attacks for collision, 2nd preimage or preimage.
practical example A practical example is given for the attack on this hash function. This is an extra category since practical examples improve the confidence in an attack.

2 Main Table

The main table should give a first impression on the remaining SHA-3 candidates. It shows only the best known attack, more detailed results are given in the individual hash function tables.

column Explanation
Hash Name More detailed information about this SHA-3 candidate is given at its WikiPage.
Best Attack on Main NIST Requirements In this column the best attack on collision, 2nd-preimage and preimage resistant is shown. To give a quick overview of the complexity of the best attack, the cells are labeled with different colors.
Best Attack on other Hash Requirements Best Attack on additional requirements for a hash function not unambiguously specified by NIST yet.
External Cryptanalysis This column should give an overview which hash functions have no external cryptanalytic results yet.

3 Individual Hash Function Tables

A dash (-) in the individual table means that the complexities are neglible. A question mark (?) means that the information is not given or unclear. We ask the authors to include these results in the abstract of their publication.

The "Parameters/Variants" column gives the parameters for attacks on reduced variants. If the column is empty, the attack is on the recommended parameters of the designers.

The "Type of Analyses" column is left white, if the attack is on reduced variants or parts of the hash function.