Joel Lathrop

Abstract

Cryptographic hash functions are a vital part of our current computer sys- tems. They are a core component of digital signatures, message authentica- tion codes, file checksums, and many other protocols and security schemes. Recent attacks against well-established hash functions have led NIST to start an international competition to develop a new hashing standard to be named SHA-3. In this thesis, we provide cryptanalysis of some of the SHA-3 candidates. We do this using a new cryptanalytical technique introduced a few months ago called cube attacks. In addition to summarizing the technique, we build on it by providing a framework for estimating its potential effectiveness for cases too computationally expensive to test. We then show that cube at- tacks can not only be applied to keyed cryptosystems but also to hash func- tions by way of a partial preimage attack. We successfully apply this attack to reduced-round variants of the ESSENCE and Keccak SHA-3 candidates and provide a detailed analysis of how and why the cube attacks succeeded. We also discuss the limits of theoretically extending these attacks to higher rounds. Finally, we provide some preliminary results of applying cube attacks to other SHA-3 candidates.

Library of Congress Subject Headings

Data encryption (Computer science); Cryptography; Coding theory; Computer security

Publication Date

2009

Document Type

Thesis

Department, Program, or Center

Computer Science (GCCIS)

Advisor

Radziszowski, Stanislaw

Comments

Note: imported from RIT’s Digital Media Library running on DSpace to RIT Scholar Works. Physical copy available through RIT's The Wallace Library at: QA76.9.A25 L38 2009

Campus

RIT – Main Campus

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