Upload
emy-zaninka
View
26
Download
0
Embed Size (px)
Citation preview
( )
.
:
K. Es Es=f(M,K) () (M,Es)
Es=f(M,K)
?
M, Es=f(M,K) M2 Es2 , Es2=f(M2,K)
Es , .. Es .
( ) Es=f(M,K) (M; Es ) : M Es K. K1, K2 .. Kl M Es , , .. .
( ) . P~2-N/2 ( N)
() ( , ).: (- . ) ( )
()MAC ( ) CBC:Ei=fK(Ei-1+Mi) ( ). ~ 128256
() : Es=f(M,k) () (M,Es)
M = g(Es,K)
?
( RSA) Es=Mk mod N () (M,Es)
M = EsK mod N
() . ( RSA): R RK mod N (RK mod N; R ) M = EsK mod N, .. => RK mod N= RK mod N , .. . () M; Es
( ) , , , : , .. .
.
: ( ) 1. xf5$ty2.DFu9*
3.gf%^h1.2.
3.123
: y=f(x) (y=ax mod N)x=(y) (x=logay mod N)
( ) :y=f(x) , .x=(y) , .y=ax mod Ny=MAC(x)
, .: :ax11. y1ax22. y2ax3 3. y3x1x2x3
x, ax mod N ( ) f()1. y12.y2
3.y31x12x2
3x3f(x1) = y1?
. ( . ).
, . . , MAC.
, .
, . .
. .
:
( ..)
() , .
.. . ()AB1KAKBAB1(M;Es)(M;Es)
.. .. .
: ,
:Es=fk(M) (M Es) , M=gK(Es) ??
:
Es=f(M,kA) (M;Es) M=f(Es,KA)?
.. RSA