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Assume a sender and receiver use basic CBC-MAC but authenticate/accept messages of different lengths. Which of the following is a valid attack?

Which of the following is a generator of Z*11?

Assume the Diffie-Hellman protocol is run by two parties in the subgroup of Z23∗ generated by 2. (This subgroup has order 11.) If the first party chooses private exponent 3 and the second chooses private exponent 10, which of the following characterizes the execution of the protocol in this case?

What is ϕ(77)?

Say we modify CBC-MAC to incorporate a random IV. So authentication of a 1-block message m using a block cipher F and key k is done by choosing a uniform IV and outputting the tag IV,Fk(IV⊕m). Verification is done in the natural way. Say this scheme is used with an 4-byte block cipher, and an attacker sees the tag 0x01 01 01 01 05 06 07 08 on the message 0x 00 00 01 01. Which of the following will be a valid message/tag pair?

If we encrypt the message 0xAF C0 4D using the one-time pad and key 0xC9 2B 39. What is the resulting ciphertext?

Which of the following is a setting in which a pseudorandom generator could be applied?

What is the size of key space |K| for a shift cipher, considering the message space as English alphabets, and encryption algorithm as Enc​(m)=(m+shift)mod 26?

What is the value (in decimal) of 0x48?

Which of the following problems is hard if the RSA assumption holds? In all the below, N is a product of distinct, large primes p and q, and e is relatively prime to ϕ(N).