Lars Ramkilde Knudsen

Last updated
Lars R. Knudsen
Born (1962-02-21) 21 February 1962 (age 62)
Nationality Danish
Alma mater Aarhus University
Scientific career
Fields Cryptography
Institutions Technical University of Denmark
Doctoral advisor Ivan Damgård

Lars Ramkilde Knudsen (born 21 February 1962) is a Danish researcher in cryptography, particularly interested in the design and analysis of block ciphers, hash functions and message authentication codes (MACs).

Contents

Academic

After some early work in banking, Knudsen enrolled at Aarhus University in 1984 studying mathematics and computer science, gaining an MSc in 1992 and a PhD in 1994. From 1997-2001, he worked at the University of Bergen, Norway. Currently, Knudsen is a professor in the Department of Mathematics at the Technical University of Denmark. Ivan Damgård was Lars' mentor during his studies at Aarhus University. His Ph.D. was refereed by Bart Preneel.

Publications

Knudsen has published a couple of papers on cryptanalysis of cryptographic primitives, including the R-MAC scheme, the SHA-1 and MD2 hash functions, and a couple of block ciphers: DES, DFC, IDEA, ICE, LOKI, MISTY, RC2, RC5, RC6, SC2000, Skipjack, Square and SAFER.

Knudsen was involved in designing some ciphers: AES candidates DEAL and Serpent (the latter in conjunction with Ross Anderson and Eli Biham). He was involved in designing Grøstl, a hash function which was one of the submissions to the NIST SHA-3 competition (it was not the winner).

He introduced the technique of impossible differential cryptanalysis [1] and integral cryptanalysis.

Related Research Articles

In cryptography, a block cipher is a deterministic algorithm that operates on fixed-length groups of bits, called blocks. Block ciphers are the elementary building blocks of many cryptographic protocols. They are ubiquitous in the storage and exchange of data, where such data is secured and authenticated via encryption.

<span class="mw-page-title-main">Cryptanalysis</span> Study of analyzing information systems in order to discover their hidden aspects

Cryptanalysis refers to the process of analyzing information systems in order to understand hidden aspects of the systems. Cryptanalysis is used to breach cryptographic security systems and gain access to the contents of encrypted messages, even if the cryptographic key is unknown.

Articles related to cryptography include:

<span class="mw-page-title-main">Eli Biham</span> Israeli cryptographer and cryptanalyst (born 1960)

Eli Biham is an Israeli cryptographer and cryptanalyst who is a professor at the Technion - Israel Institute of Technology Computer Science department. From 2008 to 2013, Biham was the dean of the Technion Computer Science department, after serving for two years as chief of CS graduate school. Biham invented (publicly) differential cryptanalysis, for which he received his Ph.D., while working under Adi Shamir. It had been invented before by a team at IBM during their Data Encryption Standard work; the National Security Agency told IBM to keep the discovery secret.

<span class="mw-page-title-main">Vincent Rijmen</span> Belgian cryptographer (born 1970)

Vincent Rijmen is a Belgian cryptographer and one of the two designers of the Rijndael, the Advanced Encryption Standard. Rijmen is also the co-designer of the WHIRLPOOL cryptographic hash function, and the block ciphers Anubis, KHAZAD, Square, NOEKEON and SHARK.

<span class="mw-page-title-main">Cryptographic hash function</span> Hash function that is suitable for use in cryptography

A cryptographic hash function (CHF) is a hash algorithm that has special properties desirable for a cryptographic application:

Joan Daemen is a Belgian cryptographer who co-designed with Vincent Rijmen the Rijndael cipher, which was selected as the Advanced Encryption Standard (AES) in 2001. More recently, he co-designed the Keccak cryptographic hash, which was selected as the new SHA-3 hash by NIST in October 2012. He has also designed or co-designed the MMB, Square, SHARK, NOEKEON, 3-Way, and BaseKing block ciphers. In 2017 he won the Levchin Prize for Real World Cryptography "for the development of AES and SHA3". He describes his development of encryption algorithms as creating the bricks which are needed to build the secure foundations online.

<span class="mw-page-title-main">DEAL</span> Block cipher

In cryptography, DEAL is a symmetric block cipher derived from the Data Encryption Standard (DES). Its design was presented Lars Knudsen at the SAC conference in 1997, and submitted as a proposal to the AES contest in 1998 by Richard Outerbridge.

<span class="mw-page-title-main">SHACAL</span> Block cipher

SHACAL-1 is a 160-bit block cipher based on SHA-1, and supports keys from 128-bit to 512-bit. SHACAL-2 is a 256-bit block cipher based upon the larger hash function SHA-256.

Akelarre is a block cipher proposed in 1996, combining the basic design of IDEA with ideas from RC5. It was shown to be susceptible to a ciphertext-only attack in 1997.

Bart Preneel is a Belgian cryptographer and cryptanalyst. He is a professor at Katholieke Universiteit Leuven, in the COSIC group.

Stefan Lucks is a researcher in the fields of communications security and cryptography. Lucks is known for his attack on Triple DES, and for extending Lars Knudsen's Square attack to Twofish, a cipher outside the Square family, thus generalising the attack into integral cryptanalysis. He has also co-authored attacks on AES, LEVIATHAN, and the E0 cipher used in Bluetooth devices, as well as publishing strong password-based key agreement schemes.

Ivan Bjerre Damgård is a Danish cryptographer and currently a professor at the Department of Computer Science, Aarhus University, Denmark.

<span class="mw-page-title-main">Cryptography</span> Practice and study of secure communication techniques

Cryptography, or cryptology, is the practice and study of techniques for secure communication in the presence of adversarial behavior. More generally, cryptography is about constructing and analyzing protocols that prevent third parties or the public from reading private messages. Modern cryptography exists at the intersection of the disciplines of mathematics, computer science, information security, electrical engineering, digital signal processing, physics, and others. Core concepts related to information security are also central to cryptography. Practical applications of cryptography include electronic commerce, chip-based payment cards, digital currencies, computer passwords, and military communications.

Grøstl is a cryptographic hash function submitted to the NIST hash function competition by Praveen Gauravaram, Lars Knudsen, Krystian Matusiewicz, Florian Mendel, Christian Rechberger, Martin Schläffer, and Søren S. Thomsen. Grøstl was chosen as one of the five finalists of the competition. It uses the same S-box as AES in a custom construction. The authors claim speeds of up to 21.4 cycles per byte on an Intel Core 2 Duo, and 9.6 cycles/byte on an Intel i7 with AES-NI.

The following outline is provided as an overview of and topical guide to cryptography:

This article summarizes publicly known attacks against cryptographic hash functions. Note that not all entries may be up to date. For a summary of other hash function parameters, see comparison of cryptographic hash functions.

Yiqun Lisa Yin is a Chinese-American cryptographer and independent security consultant. Yin is known for breaking the SHA-1 cryptographic hash function, for developing the RC6 block cipher, and for her service as editor of the IEEE P1363 project for the standardization of public-key cryptography.

Anne Canteaut is a French researcher in cryptography, working at the French Institute for Research in Computer Science and Automation (INRIA) in Paris. She studies the design and cryptanalysis of symmetric-key algorithms and S-boxes.

References

  1. Knudsen, Lars (21 February 1998). "DEAL - A 128-bit Block Cipher" (PDF). Complexity. 258 (2). Archived from the original (PDF) on 26 February 2007. Retrieved 2007-02-27.