| 摘要 |
PROBLEM TO BE SOLVED: To provide a key sharing technique that has efficiency equal to that of a conventional system and is CCA-safe (also safe for an active attack) in a standard model (a model for fixing a hash function to a concrete function). SOLUTION: A second device selects a random integer (r), performs an operation of C1=g1<SP>r</SP>, C2=g2<SP>r</SP>, d=H(z, w, C1, C2),σ=z<SP>r</SP>×w<SP>r×d</SP>, and calculates a key K=F<SB>σ</SB>(g1, g2, z, w, C1, C2). C1, C2 are transmitted to a first device. The first device performs an operation of d=H(z, w, C1, C2),σ=C1<SP>(x1+d×y1)</SP>×C2<SP>(x2+d×y2)</SP>, and calculates the key K=F<SB>σ</SB>(g1, g2, z, w, C1, C2). COPYRIGHT: (C)2009,JPO&INPIT
|
