Date de l'exposé : 23 novembre 2018
Repairing the Faure-Loidreau Public-Key Cryptosystem
A repair of the Faure–Loidreau (FL) public-key
code-based cryptosystem is proposed. The FL cryptosystem is
based on the hardness of list decoding Gabidulin codes which are
special rank-metric codes. We prove that the recent structural
attack on the system by Gaborit et al. is equivalent to decoding
an interleaved Gabidulin code. Since all known polynomial-time
decoders for these codes fail for a large constructive class of
error patterns, we are able to construct public keys that resist
the attack. It is also shown that all other known attacks fail
for our repair and parameter choices. Compared to other code-
based cryptosystems, we obtain significantly smaller key sizes
for the same security level.