| Budget Amount *help |
¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 1995: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1994: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Research Abstract |
In this study, the following coding theorems are obtained for the Shannon cipher system.
Case 1 (Secret information : discrete, Security level : entropy of secret information conditioned cryptogram)
(a) For the case of less-noisy discrete broadcast channel, the achievable region of cryptogram rate R,key rate R_k, security level h, and admissible distortion of regular receiver is determined.
(b) For the case of the Gaussian wiretap channel, the achievable region of cryptogram rate R,key rate R_k security level h, and admissible distortion of regular receiver is determined.
Case 2 (Secret information : continuous, Security level : attainable minimum distortion of wiretappers)
(a) For the case of less-noisy discrete broadcast channel, inner and outer bounds of the achievable region of cryptogram rate R,key rate R_k, security level D,and admissible distortion of regular receiver are derived.
(b) For the case of the Gaussian wiretap channel, inner and outer bounds of the achievable region of cryptogram rate R,key rate R_k, security level D,and admissible distortion of regular receiver are derived.
Case 3 (Secret information : discrete, Security level : attainable minimum distortion of wiretappers)
(a) For the case of noiseless channel, inner and outer bounds of the achievable region of cryptogram rate R,key rate R_k, security level D,and admissible distortion of regular receiver are derived.
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