Method for checking the security of a key pair of a cryptographic system based on algebraic codes

摘要

The invention describes a method for checking the security of a key pair of a cryptographic system based on algebraic codes, in particular the Faure-Loidreau cryptosystem. The key pair comprises a public key for encrypting a message and a private key for decrypting the message, the public key comprising a code word (G ∈ Gab [n, k]) of an interleaved gabidulin code. In a step a), the method according to the invention comprises determining an estimated code word (x̂G) from the public key in which a number of columns and / or rows have been deleted, using a decoder (Dec (·)) which executes an error clearing decoding algorithm. In step b), the determination of an error vector (ẑ) from the public key and the estimated code word (x̂G) is included. In step c) there is a check as to whether the error vector (ẑ) determined in step b) has a predetermined rank. Finally, in step d), the key pair which comprises the public key checked in step a) is marked as weak if the check in step c) is positive.