Lecture: Permutation-based cryptography

When

28. 4. 2022
16:30 – 17:30

Where

Lecture hall T9:105

Thákurova 9, Prague 6

Reservation

No reservation needed

Record

YouTube

Belgian cryptologist and one of the authors of the world-famous AES/Rijndael cipher, Joan Daemen, will speak exclusively at FIT CTU. His lecture will be about a counter-movement that they started to clean up symmetric cryptography. In particular, this is a re-factoring where block ciphers are replaced by cryptographic permutations and so-called deck functions as central primitives. His lecture will be followed by a lecture of Lejla Batina.

Abstract

Symmetric cryptography is the subfield of cryptography that deals with encryption, MAC computation and authenticated encryption secured by shared secret keys and cryptographic hashing. Ever since the introduction of DES in the seventies, this field has been dominated by block ciphers. Encryption, authentication and hashing are usually performed using modes of block ciphers. Over the years, an impressive panoply of modes of ever-increasing complexity has been developed: CBC, CBC-MAC, Counter-mode, GCM, Davies-Meyer with Merkle-Damgard, OCB, just to name a few. This has led to a rather messy situation.

Joan Daemen will speak about a counter-movement they started to clean up symmetric cryptography. In particular, this is a re-factoring where block ciphers are replaced by cryptographic permutations and so-called deck functions as central primitives. Important milestones in this movement were the introduction of three permutation-based constructions:

  • sponge for hashing in 2007,
  • duplex for lightweight authenticated encryption in 2011 and
  • farfalle for high-speed authenticated encryption in 2017.

It turns out that permutation-based cryptography is at the same time simpler and more efficient than old-school block cipher based crypto.

Joan Daemen

After graduating in electromechanical engineering, Joan Daemen was awarded his PhD in 1995 from KU Leuven, Belgium. After his contract ended at COSIC, he privately continued his crypto research and contacted Vincent Rijmen to continue their collaboration that would lead to the Rijndael block cipher, and this was selected by NIST as the new Advanced Encryption Standard in 2000.

After over 20 years of security industry experience, including work as a security architect and cryptographer for STMicroelectronics, he is now a full professor in the Digital Security Group at Radboud University Nijmegen (the Netherlands). He co-designed the Keccak cryptographic hash function that was selected as the SHA-3 hash standard by NIST in 2012 and is one of the founders of the permutation-based cryptography movement and co-inventor of the sponge, duplex and farfalle constructions.

In 2017, he won the Levchin Prize for Real-World Cryptography “for the development of AES and SHA3”. In 2018, he was awarded an ERC advanced grant for research on the foundations of security in symmetric cryptography called ESCADA and an NWO TOP grant for the design of symmetric crypto in the presence of efficient multipliers called SCALAR.

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