3. Most of the encryption modes require an initial vector (IV) or Nonce. Properties of an IV/ Nonce depend on the cryptographic scheme used. If we are not careful in selecting IV/Nonce, the data encrypted by us may not be secure at all, even though we are using a secure encryption algorithm and mode. a. A basic requirement for IV is uniqueness, which means that no IV may be reused under the same key. One may argue that if the plaintext does not repeat, using the same IV is safe. Let us look at the Output Feedback (OFB) mode. Assume that the attacker gets hold of a plaintext (P1) and a ciphertext (C1), can he/she decrypt other encrypted messages if the IV is always the same? You are given the following information, please try to figure out the actual content of P2 based on C2, P1, and C1. Hint: you can use an online XOR calculator. Plaintext (P1) in hex: 546869732069732061206b6e6f776e206d657373616765210a Ciphertext (C1) in hex: a469b1c502c1cab966965e50425438e1bb1b5f9037a4c159 Plaintext (P2): (unknown to you) Ciphertext (C2) in hex: bf73bcd3509299d566c35b5d450337e1bb175f903fafc159