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Theses

Nonlinear dynamics, applications to chaos-based encryption

Abstract : Chaotic systems are known to exhibit complex nonlinear dynamics. They present both random-like and deterministic features, which render chaos-based encryption very promising for the design of secure cryptosystems. Chaos-based cryptosystems can be classified into stream ciphers and block ciphers. A well designed pseudo-chaotic number generator (PCNG) with enhanced chaotic features and pseudo-randomness plays a crucial role in the security of a chaos-based cryptosystem. However, an insufficient level of confusion and diffusion in the encryption algorithm and unreliable PCNGs may lead to a security breach. Meanwhile, the adopted real number domain defined chaotic maps may menace the reliability of a chaos-based cryptosystem. In this thesis, the chaotic maps under investigation have been reformulated over a finite N-bit (N=32) integer field, which overcomes the quantification problems and reduces the resource utilization. In addition, a new stream cipher based on an efficient PCNG and a robust block cipher based on chaotic components and the S-box of Advanced Encryption Standard (AES) with excellent confusion and diffusion properties have been proposed. Both have been verified to be secure and reliable. Furthermore, a pseudo-random number generator (PRNG) framework based on a newly designed smart coupling of chaotic maps has been explored. It has good flexibility and can be used in cryptographic or other PRNG required applications.
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https://hal.archives-ouvertes.fr/tel-03200707
Contributor : Zongchao Qiao Connect in order to contact the contributor
Submitted on : Friday, April 16, 2021 - 5:14:09 PM
Last modification on : Wednesday, April 27, 2022 - 3:45:57 AM
Long-term archiving on: : Saturday, July 17, 2021 - 7:16:46 PM

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  • HAL Id : tel-03200707, version 1

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Zongchao Qiao. Nonlinear dynamics, applications to chaos-based encryption. Cryptography and Security [cs.CR]. École centrale de Nantes, 2021. English. ⟨NNT : 2021ECDN0016⟩. ⟨tel-03200707⟩

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