This questions only require YES or NO answer without any motivation. 1. (T/F)In theory, if the key..

This questions only require YES or NO answer without any motivation. 1. (T/F)In theory, if the key is truly random, never reused, and kept secret DES and AES are both provably secure against known plaintext attacks. Solution FALSE, not provably secure but rather computationally secure. 2. (T/F) A Feistel cipher structure lets you use the same hardware or software for decryption as for encryption. Solution TRUE, just reverse the order of the subkeys. 3. (T/F) All block ciphers use S-boxes and permutation P-boxes. Solution FALSE, IDEA does not have S and P boxes, though achieving confusion and diffusion by other means. 4. (T/F) DiffieHellman key exchange is an asymmetric scheme that can be used for encryption and signatures, but is not as efficient as RSA. Solution FALSE, DH is only used for key exchange, see also the textbook. 5. (T/F) A hash function given by h(m1, m2) = me 1me 2 (mod pq), (where p, q are RSA primes and e has the inverse (mod f(pq))) is a collision resistant hash functions, that is it is computationally hard to find (m0 1 , m0 2 ) such that h(m1, m2) = h(m0 1 , m0 2 ). Solution FALSE, e.g. one can take (m0 1 , m0 2 ) = (m2, m1) and get a collision.