CSC $435$ Homework $2($Due Date September $29$th$)$

$1.$ Decipher the following Caesar cipher

RsvjspoWxexiMpszicsy,RsvjspoWxexiMamppepaecwfixvyi

$2.$ In an RSA system, p $=13,$ q $=11,$ e $=7,$ encrypt the plaintext $12$

$3.$ In an RSA system you intercept the ciphertext C $=8$ sent to a user whose public key is

e $=7,$ n$=91,$ what is the plaintext

$4.$ Consider a Diffie$-$Helman scheme with a common prime q $=11$ and

a primitive root $\backslash$alpha $=2$

a$.$ If user A has public key YA $=9,$ what is A$$s private key XA$?$

b$.$ If user B has public key YB $=3,$ what is the shared secret key K$?$