Description
In 2005, Faure and Loidreau proposed a new rank-metric cryptosystem inspired from the Hamming metric scheme of Augot-Finiasz in 2003. In 2018, it was broken by the attack of Gaborit, Otmani and Kalachi. Recently, there are some attempts of repairing the Faure-Loidreau scheme, for example the work of Renner, Puchinger and Wachter–Zeh which is called LIGA. In this thesis, we also introduce a new cryptosystem so-called RAMESSES which is another repairing of Faure-Loidreau scheme.<br/> Besides, we also study about the recent attack of Coggia and Couveur in the Loidreau's cryptosystem (2017). Although they only propose an idea for a special case of the dimension of secret subspace, this attack can be generalized. In this thesis, we propose an analysis of Coggia-Couvreur attack on Loidreau’s rank-metric public-key encryption scheme in the general case. The last part is a study about the decoding of the sum of Gabidulin codes which is inspired from the work of Loidreau in 2005 "Welch-Berlekamp Like Algorithm for Decoding Gabidulin Codes". This work is also an attempt to repair the Loidreau's cryptosystem (2017) to avoid the Coggia-Couveur's attack.<br/> lien:
Next sessions
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Lightweight (AND, XOR) Implementations of Large-Degree S-boxes
Speaker : Marie Bolzer - LORIA
The problem of finding a minimal circuit to implement a given function is one of the oldest in electronics. In cryptography, the focus is on small functions, especially on S-boxes which are classically the only non-linear functions in iterated block ciphers. In this work, we propose new ad-hoc automatic tools to look for lightweight implementations of non-linear functions on up to 5 variables for[…]-
Cryptography
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Symmetrical primitive
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Implementation of cryptographic algorithm
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Algorithms for post-quantum commutative group actions
Speaker : Marc Houben - Inria Bordeaux
At the historical foundation of isogeny-based cryptography lies a scheme known as CRS; a key exchange protocol based on class group actions on elliptic curves. Along with more efficient variants, such as CSIDH, this framework has emerged as a powerful building block for the construction of advanced post-quantum cryptographic primitives. Unfortunately, all protocols in this line of work are[…] -
Endomorphisms via Splittings
Speaker : Min-Yi Shen - No Affiliation
One of the fundamental hardness assumptions underlying isogeny-based cryptography is the problem of finding a non-trivial endomorphism of a given supersingular elliptic curve. In this talk, we show that the problem is related to the problem of finding a splitting of a principally polarised superspecial abelian surface. In particular, we provide formal security reductions and a proof-of-concept[…]-
Cryptography
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