Provable Security for Block Ciphers by Decorrelation

Quantitative Security of Block Ciphers: Designs and Cryptanalysis Tools

Block ciphers probably figure in the list of the most important cryptographic primitives. Although they are used for many different purposes, their essential goal is to ensure confidentiality. This thesis is concerned by their quantitative security, that is, by measurable attributes that reflect their ability to guarantee this confidentiality. The first part of this thesis deals with well know ...

On a Structure of Block Ciphers with Provable Security against Differential and Linear Cryptanalysis

We introduce a new methodology for designing block ciphers with provable security against differential and linear cryptanalysis. It is based on three new principles: change of the location of round functions, round functions with recursive structure, and substitution boxes of different sizes. The first realizes parallel computation of the round functions without losing provable security, and th...

New Structure of Block Ciphers with Provable Security against Differential and Linear Cryptanalysis

Abst rac t . We introduce a methodology for designing block ciphers with provable security against differential and linear cryptanalysis. It is based on three new principles: change of the location of round functions, round functions with recursive structure, and substitution boxes of different sizes. The first realizes parallel computation of the round functions without losing provable securit...

Resistance Against General Iterated Attacks

In this paper we study the resistance of a block cipher against any general iterated attack. This class of attacks includes diierential and linear cryptanalysis. We prove that we can upper bound the complexity of the attack by using Vaudenay's decorrelation technique. Our main theorem enables to prove the security of some recently proposed block ciphers COCONUT98 and PEANUT98. Since public-key ...

Provable secure scalable block ciphers