Dr. Dmitry Khovratovich, Microsoft Research
Monday, June 11, 2012 - 9:45am
Host: Prof. Bruce Tidor, MIT
Contact: Nira Manokharan firstname.lastname@example.org
Refreshments at 9:45am, Seminar at 10am
Abstract: The new digital world has brought numerous challenges in security
and privacy, among which the design of a secure encryption scheme is foundational for protecting the confidentiality of data. The contemporary standard of encryption, AES, has been selected in an open competition over a decade ago. Despite intensive cryptanalytic efforts and hundreds of papers written on the subject, no weakness has been found in the design of AES. It is now implemented in software and hardware across the world: from Web browsers and hard drive protection mechanisms to smart cards and microprocessors. We present and discuss the first method of analysis that reduces the security level of the full AES disregard the key length. Our attack was inspired by an earlier analysis of hash functions based on bipartite graphs (bicliques). Our analysis has provoked many discussions across the world on the security margin of AES. It also motivated researchers to challenge the security of other ciphers and hash functions, with more than 20 papers citing our attack. Bio: Dmitry Khovratovich graduated from Moscow State University in 2005, and got his PhD in cryptanalysis in the University of Luxembourg in 2010. Since Aug 2010 he has been a post-doc researcher at Microsoft Research Cryptography Group. Dmitry is an author of the first attacks on the full version of the AES cipher in various settings, an inventor of rotational cryptanalysis, and an author of the best state recovery attack on the stream cipher RC4. He is a recipient of multiple awards, including the Best Paper Award at the conference Asiacrypt 2010 for the analysis of the SHA-3 candidate Skein, and the Outstanding Scientific Publication Award from the Luxembourgian Research Fund for his analysis of AES.