| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent distributed contents from being illegally copied even by high-level illegal copy techniques. <P>SOLUTION: By using a reproduction/management device 20 and an IC card 10 having a common authentic key Ka, a random number r2 generated by the reproduction/management device 20 is exactly distributed to the IC card 20 and in the reproduction/management device 20, an enciphered contents key E (r2, Kc) received from the IC card 10 is deciphered by the random number r2 so that contents data C can be reproduced by the obtained contents key Kc. Namely, since the IC card 10 is required for reproducing the contents, the illegal copy is made extremely difficult. <P>COPYRIGHT: (C)2003,JPO |
