= 19?
Q8(1 point). Using the same notations as in the lecture, e.g., p and q are the two
primes and e and d are the public key and the private key, respectively, p = 7, q
= 13 and e=7. The attacker performs a chosen-ciphertext attack (CCA). It has a
known ciphertext 18 and wants to retrieve the corresponding plaintext. It
computes c'=c*r^e mod n and chooses the ciphertext 18*128 mod 91 = 29 and
retrieves the corresponding plaintext, 29. What is the plaintext corresponding to
the ciphertext 18?
Q9(1 point). Alice and Bob use Diffie-Hellman Key Exchange to share a key
with a common prime p = 13 and a primitive root a-2. If Alice has a public key
Y_A=9, what is her private key X_A?
Q10(1 point). There are 8 computers (hardware). Each computer hosts 4 virtual
machines (VM) with different addresses, and each VM hosts 10 applications.
How many key exchange sessions (in one session, two logical parties share a
key) are needed if the decentralized key distribution is used so that all
applications share a pair-wise keys?
