| 摘要 |
A first of two cryptographic units (12a, 12b) establishes a cryptographic key "K" by initially selecting a first quantity "A", and computes second and third quantities "B" = phi 1(A) and "C" = phi 2(A). Computing A from B and the function phi 1 must be mathematically impossible. The first unit (12a/12b) then transmits B to the second cryptograpic unit (12b/12a) retaining C. The second unit (12b/12a) selects a fourth quantity "D" and computes fifth and sixth quantities "E" = phi 3(D) and "F" = phi 4(D). Computing D from E and the function phi 3 must be mathematically impossible. Upon receiving B, the second unit (12b/12a) uses a fifth mathematical function " psi 2" to compute the key "K" = psi 2(F, B) = psi 2( phi 4{D}, phi 1{A}). Analogously, upon receiving E the first unit (12a/12b) uses a sixth mathematical function psi 1 to compute the key "K" = psi 1(C, E) = psi 1( phi 2{A}, phi 3{D}) = psi 2( phi 4{D}, phi 1{A}). |
