| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an information provision system which prevents a "runaway with information"-problem in which an information provision device providing information first suffers a disadvantage in providing information between devices with no mutual trust, the problem caused by another information provision device which has received the information from the information provision device provides no information of its own. <P>SOLUTION: An information provision device 12-1 gives a mediation device 11 capability of re-encrypting an encrypted text C<SB POS="POST">1,1</SB>owned by the information provision device 12-1 into an encrypted text C<SB POS="POST">1,2</SB>. An information provision device 12-2 gives the mediation device 11 capability of re-encrypting an encrypted text C<SB POS="POST">2,1</SB>owned by the information provision device 12-2 into an encrypted text C<SB POS="POST">2,2</SB>. The mediation device 11 uses the provided capability to re-encrypt the encrypted text C<SB POS="POST">1,1</SB>into the encrypted text C<SB POS="POST">1,2</SB>and re-encrypt the encrypted text C<SB POS="POST">2,1</SB>into the encrypted text C<SB POS="POST">2,2</SB>. Then the mediation device 11 outputs the encrypted text C<SB POS="POST">1,2</SB>to the information provision device 12-2 and outputs the encrypted text C<SB POS="POST">2,2</SB>to the information provision device 12-1. <P>COPYRIGHT: (C)2013,JPO&INPIT |
