DATA CONVERSION APPARATUS AND DATA CONVERSION METHOD

摘要

Input data (101) on A and input data (102) on B are processed. First nonlinear conversion is made for the input data (101) on side A with a first key parameter (111). The exclusive-OR of the result (109) of the first nonlinear conversion and the input data (102) on side B appears as intermediate input data (106) to a sub-conversion processing portion (122) of the next stage on side B, while the input data (102) on side B undergo the second nonlinear conversion with a second key parameter (112) in the sub-conversion processing portion of the next stage on side A. The exclusive-OR of the result of this second nonlinear conversion and the intermediate data (106) is input as the intermediate data (108) to the sub-conversion processing portion (123) of the next stage on side B. The structures described above are cascaded, and the intermediate data in the final stages on sides A and B form the converted output data (103 and 104).