Decoding Interleaved Gabidulin Codes and Ciphertext-Security for GPT variants

In this paper we view interleaved Gabidulin codes and describe how to correct errors up to a rank equal to the amount of redundancy of the code with high probability. We give a detailed proof for our estimation of the probability of correct decoding. In a second part, we view the application to variants of the GPT cryptosystem. For GGPT this leads to an efficient attack on the remaining secure instances, whereas it allows to derive at least partial information of the plaintext in the case of RRC-GPT.