New Analysis on Security of Stream Cipher HC-256

HC-256 proposed by Wu Hongjun at FSE 2004 is a software-efficient stream cipher algorithm based on table-driven, which is proposed as a final candidate to the eSTREAM project. In this paper, we modified the original version of HC-256 by removing the constant in the key expansion function, which we denoted HC-256*. Then we make a related-key security analysis on HC-256* and receive a conclusion that HC-256* is provable security under the related-key attack.