On paddings of MULTI-S01 and their security evaluation

摘要

For operation of encryption, padding, adding a specifed data to an original message, is important element of encryption algorithm, sometimes being relevant to security. In this paper, we discuss the padding of the MULTI-S01 cipher. In the previously proposed scheme, the length of the message must be known before the beginning of encryption. This assumption cannot be realized at some circumstances. We therefore propose the new padding method to solve the problem. As a result we proved that the scheme with the new padding method is as secure as the scheme with the previous padding method.