International Association for Cryptologic Research

Ph.D. Database

The aim of the IACR Ph.D. database is twofold. On the first hand, we want to offer an overview of Ph.D. already completed in the domain of cryptology. Where possible, this should also include a subject classification, an abstract, and access to the full text. On the second hand, it deals with Ph.D. subjects currently under investigation. This way, we provide a timely map of contemporary research in cryptology. All entries or changes need to be approved by an editor. You can contact them via phds (at) iacr.org.

Details

Marc Stevens (#832)
Name Marc Stevens
Personal Homepage http://marc-stevens.nl/research
Institution Leiden University
Topic of his/her doctorate. Attacks on Hash Functions and Applications
Category secret-key cryptography
Keywords hash functions, MD5, SHA-1, differential analysis, collision attack, implementation
Year of completion 2012
Abstract Cryptographic hash functions compute a small fixed-size hash value for any given message. A main application is in digital signatures which require that it must be hard to find collisions, i.e., two different messages that map to the same hash value. In this thesis we provide an analysis of the security of the cryptographic hash function standards MD5 and SHA-1 that have been broken since 2004 due to so called identical-prefix collision attacks. In particular, we present more efficient identical-prefix collision attacks on both MD5 and SHA-1 that improve upon the literature. Furthermore, we introduce a new more flexible attack on MD5 and SHA-1 called the chosen-prefix collision attack that allows significantly more control over the two colliding messages. Moreover, we have proven that our new attack on MD5 poses a realistic threat to the security of everyday applications with our construction of a rogue Certification Authority (CA). Our rogue CA could have enabled the total subversion of secure communications with any website -- if we had not purposely crippled it. Finally, we have introduced an efficient algorithm to detect whether a given message was generated using an identical-prefix or chosen-prefix collision attack on MD5 or SHA-1.
E-Mail Address marc (at) marc-stevens.nl
Last Change 2013-03-01 11:01:41
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