| 摘要 |
<P>PROBLEM TO BE SOLVED: To efficiently decrypt a cipher text using an ID base cipher to be recorded in a general-purpose terminal by a highly-reliable terminal. <P>SOLUTION: A decryption system of the present invention includes a general-purpose terminal, a highly-reliable terminal, and a key generation device. The key generation device includes a secret key generation section and a cipher key generation section. The highly-reliable terminal includes a specific data transmission section, a random number generation section, an elliptic scalar magnification section, a session key calculation section, and a decryption section. The general-purpose terminal includes a bearing section and a transmission section. The elliptic scalar magnification section defines a value, which is obtained by magnifying a cipher key p by elliptic scalar through the use of a random number x, as a mask key p'. The bearing section of the general-purpose terminal acquires a mask session key k' as in an equation of k'=e(p',R), based on the mask key p' and an encryption session key R as against a cipher text C. The session key calculation section acquires a session key k, based on the mask session key k', through the use of the inverse element of the random number x. The decryption section acquires a plaintext M by decrypting the cipher text C through the use of the session key k. <P>COPYRIGHT: (C)2012,JPO&INPIT |
