() ( ) .
, . DES, IDEA, AES (Rijndael), 28147-89. , .
S-DES, DES.
1. () S-DES. . 1 ().
|
| L | R | |||
| i | ||||
Rl=il/(R0^k)L0
1 S-DES
8- (IP), .1. 0 7,
.
1 IP
7 6 4 0 2 5 1 3
7 ,
, L0, R0. ,
IP, L0 R0 . L x Rx, :
/, DES, , .
L x R x ,
L2 R2.
L2\\R2 , ,
. .
2. . 10- (0) 8-
£(8)i £(8)2. (0),
0 9, -1, . 2.
2 - -1
(9,7,3,8,0) 0, - (2,6,5,1,4) D 0. 0 D 0 , 1 D 1. 1 || D 1 , . 3.
3 -2
5 3 9 7 2 8 6 4
-2 £(8). &(8) ,
, 1 .
|
|
|
3. . . 2
4- (), . 4, 8- . mod2 8- £(8)., / = 1,2 ^ 0
S1 (. . 5 . 6).
4
3 0 1 2 1 2 3 0
5 S 0
6 S 1
| s0 | ||||
| s 1 | ||||
, mod2 , (0,1,2,3) 0,
(4,5,6,7) 1. 0 1
S 0 S 1, .
4- , . 2- S 0(B 0) || S 1(B 1). 4- (), . 7.
7 ()
1 0 3 2
y/$Li,k($)is = 1,2.
. 1993 . DES, [4].
, . -, .
, P(xt =l) = p, P(xt = 0) = 1 - , = 0,5. ( ) :
A = |l- 2 /?| , = 6{, bt = Gfcl ', ck = $1 - .
Amax = 0,5. :
1) ;
2) ( ) .
.
1. . S- /.
|
|
|
Qt (/, j), : t = 0,1 - S-, = 14, j= 1,2. Qt{i,j) mod2 mod2 . i,y. ,
- S-. , mod2, .
Qt(i,j) i*,j*, :
Qt(i*,j*):mxx\Qt(i,j)-$. (2)
\,j*, mod2, :
| Q{i J) |
L
(X, 7) = X ajxj 0 X bjyj = Y.ckkk> = ■ (3)
/= 1 /= 1 =\
2.
(1) (2) ()
3. (), 7 (), = \
:
f{X{rn)jm) = ^* @ ^* (4)
4. 1 (4):
1
v^I^^jW), (5)
:
1, v>0,5,
d = \ (6)
[0, v<0,5.
5. , (4) (6)
L
Y.clkk=d- (7)
1 (7)
* = 1 X 2,.. Xl-
Cryptoanaliz.
2.1.
, [1-4], : (, , ), S-DES, , Cryptoanaliz.
2.2.
. 5 , . Cryptoanaliz.
:
1. Cryptoanaliz
.
2. , .
3. Q0 Q1,
mod2, . 8.
8
| ^ = 1 -2\ | |||
| ^0 |
S \
4.
(5), (6)
.
5. , (7). 8- . S-DES, 10- . 10- 8- .
|
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6. .
7. , .
:
1. S-DES
.
2. Q 0 Q 1, (. 8).
3. .
4. .
5.
.
1. . .
.
2. .
3. .
4. .
5. DES.
6. 28147 - 89.
7. .
8. .
9. .
1. ., .., .. : . 2- . .: , 2002.
2. .., ., .., .. : . . : , 2003.
3. .., .. . : - , 2003.
4. .., .. . . : - , 2003
