| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an encryption device that securely prevents leakage of stored files. <P>SOLUTION: An original file 20 is first encrypted with a session key 31 generated in a file transfer source device 1 to form an encrypted file 21. The session key 31 is next encrypted with a public key 32 for the file transfer source device 1 and attached to the encrypted file 21 to form an undivided file 22. The undivided file 22 is then decomposed into partial bit strings smaller than the encryption block size of the encryption using the session key 31 and assigned to a plurality of divided files 23 to 25 in the partial bit string units, which are stored in a plurality of devices 1, 2a and 2b respectively. The construction of each divided file from the partial bit strings can prevent unauthorized decryption of each single divided file and accordingly can securely prevent leakage of the entire file 20. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
