Polar code-based secure channel coding scheme with small key size

摘要

In this study, the secret polar encoding and secret successive cancellation decoding algorithms are introduced; with these algorithms, secure and efficient communication can be enhanced between the honest parties. Also, the key size of the proposed polar code-based secure channel coding system is reduced significantly compared to the existing systems. To decrease the key size, the authors employ the three following methods: (i) a new approach is proposed to save some bit-channel indices instead of saving the generator matrix of the used polar code; (ii) the permutation and scrambling matrices are not used in this scheme; and (iii) by the help of the properties of polar codes, it does not need to save any vector as part of secret key set to generate an error vector. Moreover, the security analyses demonstrate that this system is resistant against conventional attacks on symmetric-key code-based cryptosystems. It means that reducing the key size of the proposed polar code-based scheme does not affect its security level.