Polynomial-time plaintext recovery attacks on the IKKR code-based cryptosystems

Recently, Ivanov et al. proposed a new approach to construct code-based cryptosystems, namely the $ {\sf IKKR} public-key encryptions (PKE) in International Workshop on Code-Based Cryptography (CBCrypto 2020) [9]. Unlike usual construction encryption schemes which has restrictions Hamming weight of error introduced into ciphertext, allows vectors arbitrary being ciphertext. Using this approach, constructed two modified and upgraded $-PKE. This paper aims discuss practical security In particular, we describe weaknesses design public key used We exploit such propose attacks recover plaintext The our first attack is similar LCKN [12], whilst second more efficient than attack. Our experimental results show that can from given ciphertext less 176 milliseconds for based random Goppa codes BCH codes.