DECODING KEY MANAGEMENT METHOD, COMPUTER ADOPTING THE METHOD, AND SOFTWARE METHOD AND SYSTEM USING THE KEY

摘要

PROBLEM TO BE SOLVED: To improve the reliability or a software distribution system using a cipher by increasing the number of degrees of freedom of erasing and re- installation of ciphered software. SOLUTION: A decoding key to decode a ciphered software main body 103 is preserved in a decoding key storage part 13 correspondingly to the software ID. An installer 101 retrieves the decoding key storage part 13; and if the pertinent decoding key is not found, the decoding key is obtained from a software vendor 104 by communication with this vendor 104. After this decoding key is stored in the decoding key storage part 13 corresponding to the software ID, the software main body 103 is decoded and is installed to a hard disk device 12. Since the key is reused at the time of decoding the software main body 103 again, it is unnecessary for a user to get the decoding key from the vendor 14 plural times.