CODE STRING ENCRYPTION METHOD, APPARATUS AND ENCRYPTION RELEASE METHOD, APPARATUS AND RECORDING MEDIUM

摘要

PROBLEM TO BE SOLVED: To heighten the safety of a quality improving file for improving the quality of a demo audio code string. SOLUTION: An original code string is decomposed to demo data 881 and quality improving data 882 by a code string decomposing means 1881. The quality improving data 882 is decomposed to completely or almost patterned data 883 and other data 884 in a high-quality data separationg means 1882. The data 883 are not encrypted or encrypted by different encryption processing from that of the data 884. Consequently, encryption of other important data is prevented from being decrypted. COPYRIGHT: (C)2004,JPO