※ 引述《tool11 (:))》之銘言：
: 2.
: In the RSA encryption scheme,we first find two primes p and q , and then
: determine two integers e and d such that ed≡1 (mod (p-1)(q-1)).That is ,
: the public key e is the inverse of the private key d in the modulus(p-1)(q-1).
: Let p=11,q=17 and e = 7. Determine the value of d.
: n=p*q =11*17=187
: ψ(n)=(p-1)(q-1)=10*16=160
: -1
: d=e mod ψ(n)
: 到這就不行了 ~"~
一個多月沒碰離散數學了
憑印像解
160 = 7 * 22 + 6
7 = 6 * 1 + 1
=> 1 = 7 - 6
= 7 - ( 160 - 7 * 22 )
= 160 * (-1) + 7 * 23
so, 7*23 = 1 (mod 160)
Ans: d = 23
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