64 bit kay On average, how many attempts are required to brute-force a 641 Attempts b. 20 attempts e 2 attempts d 642 attempts tes that 3 The avalanche effect of a cipher is a property that causes a a. A smal change in the key and (or) plain text significant change in the cipher text (e.g.a in the ciphor text flip) b. A very long key should be unbreakable c. A large number of rounds must be used by the cipher , C d. The cipher must be computationally secure 4 Given that p represents the plain text, k represents the kay represents the cipher text and E represents the encryption function Which of the following is a representation of the generalized Ceasar cipher a. C=E(k , p ) = (p + k ) mod 26 b, C=E(k , p)s (p . k ) mod 25 c, C=E(k , p ) = (p + k ) mod 25 d, C-E(k , p ) = (p * k ) mod 26 5. One of the challenges posed by the ideal block cipher is the very large key length. What is the key length of an n-bit ideal block cipher? a. 2n bits b. n2 bits c. n*2n bits d. n bits PART 2 (STRUCTURED QUESTIONS 10 POINTS) 6. Figure 1 and Figure 2 summarize the process followed by the S-DES algorithm (a simplified version of DES). Use this cipher to encrypt the plain text: 11011100, using the key: 1111100000. Note: Complete only one round of the encryption process. Details of the S-boxes and transposition operations are included in the appendices