| 摘要 |
PROBLEM TO BE SOLVED: To dynamically create a sub-key Ki used for each data diffusion stage i at each stage i, of which the main key cannot easily exposed even if the sub key is made known. SOLUTION: This device divides a main key K into m-pieces of keys K1,..., Km of n-bits each, and sequentially performs processing of summing character conversion processing S (k'i) to k'i, further its inversion processing P (S(k'i)), and a key Kj into k' about j=1, 2,..., m, using the sum of an arbitrary constant Ci dependent on i as an initial value of k'i and outputs finally obtained k'i as the sub-key ki.
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