RSA 1977 . (Ronald Rivest), (Adi Shamir) (Leonard Adleman). ( ) .
, , M n (M<n) :
M (n)1(mod n), | (2.14) |
(n) - . n, n. , (1) 1. , a b (a b) (a) (b).
. M , 0≤M<n. : (2.14)
e . d ,
MCd (mod n)(M e) d (mod n) M ed (mod n). | (2.15) | ||
, | , | ||
M (n)1 (mod n) , , | M k (n)1 | M (mod n), k | |
. c (2.15) , e d :
edk (n)1 | ed 1(mod(n)). | (2.16) |
, n | pq, p q , |
p q. , p 1 (p) p 1. , , p q ( , ), :
(pq)(p)(q)(p 1)(q 1). | (2.17) |
RSA . .
1) p q, p q.
2) n: n = p q. , RSA n .
3) | d, |
1 d (p 1)(q 1) (d, (p-1)(q-1))=1. | |
4) | e : |
1 e (p 1) (q 1)
e d 1 mod((p 1)(q 1))
, , (d, (p-1)(q-1))=1 e .
, (n, e) d.
.
(n,e). M , M < n. :
CM e mod n | (2.18) |
C . | |
d (2.22). | |
MCd mod n | (2.19) |
|
|
. M d ( ):
SM d mod n | (2.20) |
, . . (M,S). (n,e) : | |
M ' S e mod n. | (2.21) |
M M' , .
, . RSA . , p q , :
- ;
- (p-1) (q-1) ;
- (p-1), (q-1) (, (p-1) = 2t, t ).
, , . , , , . , , p 1 x<p, x p 11 mod p. x, , , .
e 4) [7,9,12].
3.4.4 -
1984 - (Taher Elgamal) , . - , -: .
. ,
(-1) , , 1 < < (p-1) a p.
: x (0 < x < ) y a x mod p.
(0 ≤ < ), .
1. k , 1 < k < p-1, (k,-1)=1.
2. ryk mod p.
3. ,
: c 1 ak mod p, 2 rM mod p.
, [10] ,
2' r M, 2.
. , c2 M, r. , x c1 : c 1 x (ak) x r mod p. M c 2 r 1 c 2 (c 1 x) 1 mod p. 2: M c 2' c 1 x mod p.
|
|
- , k, . , ' , , . , , M, c1 c2, c1' 2'. - , k , r r', c1 1'. ' :
Mcr 1mod p; | M ' c ' r 1 | c | ' Mc 1 mod p. | (2.22) | |
- | |||||
. , DSA (. Digital Signature Algorithm).
, a p. , x y a x mod p.
M | |||
0 | M < p. | r s (0r < p, | |
0 | s < p), : | ||
aMyr r s mod p | (2.23) |
, , . x r s. .
1. k: 1 < k < p-1, (k,-1)=1.
2. rak mod p.
3. s Mxrks mod(p 1). , : p , a , 1<a<p ( , a p xy mod(p1) x, y.
, s (M xr) k 1mod(p 1). (k,-1)=1, s .
(M,r,s) , , (2.23), .
-, , k .