pp p pp p p p . p p p p DES, p p. p p p p. p p .
, 28147-89, , .
p , p , p p.
, , , , , , , .
28147-89, DES, 256- , 32- . , .
p pp p , , p p p DES, p p. , . - . p .
, 28147-89. , , . , . , , , , .
, , . , , , . p , . p , p :
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- AB - 2;
- A[+]B - 232;
- A{+}B - 232-1.
p pp pp pp p p. p W 256 , p 32-pp x (i):
W=X(7)X(6)X(5)X(4)X(3)X(2)X(1)X(0)
p , p p p .
p p - .
p p 64 , p T(j).
p T(j) p B(0) A(0) 32 (p ). p p p, p, p i:
* i=1, 2,..., 24, j=(i-1)mod 8;
A(i) = f (A(i-1) [+] x (j)) B(i-1)
B(i) = A(i-1)
* i=25, 26,..., 31, j=32-i;
A(i) = f (A(i-1) [+] x (j)) B(i-1)
B(i) = A(i-1)
* i=32
A(32) = A(31)
B(32) = f (A(31) [+] x (0)) B(31).
i p p. f - p.
p p 32-pp p.
p p K. 8 (1)...(8) 64 . 32-pp p p 8 4-pp p, p pp 4-pp p , p 16 0...15. p p p p , p p. 4-pp p 32-pp .
p p - 32-pp p, p . 64-pp p p
=(32)(32).
p p p p .
, p p p p.
p p p p p.
p , p 64-pp T(i) (i=1,2,...,m)(m p p ), p p p pp 2 p , p p 64 , ..
=((1),(2),....,(m)).
p p p p p :
(i)=A(Y(i-1) C2, Z(i-1)) {+} C(1) T(i)=(i) T(i)
p (i) 64-pp p , - p p p (p 32-pp ). 1 2 - , 28147-89. Y(i) Z(i) p p p pp p:
(Y(0),Z(0))=A(S), S - 64-pp
(Y(i),Z(i))=(Y(i-1) [+] C2, Z(i-1) {+} C(1)), i=1, 2,...,m.
64-pp , p, p p, p p, p.
p p p p. p p p , p 64-pp T(i), p pp 2 p , p p 64 :
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=((1), (2),..., (m)).
p p p p p p:
(1)=A(S)T(1)=(1)T(1),
(i)=A((i-1)T(i)=(i)T(i), i=2, 3,..., m.
28147-89 p p p , p p p p. - p ( p), p p p p . p p . pp p p p .
p p 64 . p p (1) p pp, p 16 p p p . p , p . 64-pp p p (2) p 16 p p p . pp p m . 64-pp p p p p .
p p . p p p p p . .