A variant of the McEliece cryptosystem with increased public key security

We propose a new variant of the McEliece cryptosystem which ensures that the code used as the public key is not permutationequivalent to the secret code. This allows to increase the security of the public key, and to reconsider possible adoption of classical families of codes, like Reed-Solomon codes. A reduction in the key size or, equivalently, an increased level of security against information set decoding are the main advantages of the modified cryptosystem. As a drawback, the domain of intentional error vectors must be restricted, but we show that this has no significant impact on the security level.