Mail Archives: djgpp/1999/11/17/19:08:17
Son Ho Yong (sansam AT kornet DOT net) wrote:
: I'm student
: In Cryptology Math Problem!! T_T
: Question!!!!
: Method "Rabin Algorithm" RSA Key Creation
: First n = 2**s * m + 1 s,m calculate and to next
: 1. i <- 0
: 2. a(2<= a <= n-1)
: 3. y=A*m mod n y=1 or y=n-1 go 5 //// HELP!!!! What Mean!!
: 4. i<- i+1 i=s go 6. y<- y**2 mod n y=n-1 go 5,,,,, y=1 go 6.
: 5. prime Number
: 6. Other Number
: O(|n|**3)
: Comment : 13 = 8(mod5), 3= 1/2 mod 5, What Mean!!!!
: ' =' ='ΒΊ'
: I Know "13 mod 5 = 3"
You are confused because "mod" means different things in math-lingo
("13 = 8(mod5)") and in Pascal/C-lingo ("13 mod 5 = 3"), although
their meanings are similar.
Pascal/C-lingo:
"13 mod 5 = 3" (as you know): this means taking the remainder of the
(integer) operation 13/5. Or to put it in another way, 13 = 5*n + 3
for some n (n = ..., -2, -1, 0, 1, 2, ...). Here we see that this is
true for n = 2.
Math-lingo:
"13 = 8(mod5)" means 13 = 5*n + 8 for some n (n = ..., -2, -1, 0, 1,
2, ...). Here we see that this is true for n = 1.
In the same way we can state "13 = 8 = 3 = -1 = -4 = 4354353(mod 5)"
in math-lingo.
As for "3= 1/2 mod 5": you probably mean "3= 1/2 (mod 5)" in
math-lingo, right? For this you need to figure out what the operation
"/2" does in Z(5), I think. Or perhaps you can apply what I said about
13 = 8(mod 5)?
Right,
MartinS
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