Question 1: 1. How many different Vigenere keys of length 4 are there for coding the English alphabet? The last string must be of size 2 to get to 26. 2. Say you have an n block of bits message. You split it to 8 bits each (assume that 8 divides n). For each of the 8 bit we choose a permutation of the bits. How many different codes could come out of this? 3. For any two bits ali, Yi, define x, XOR y = 2x + y mod 2. For two vectors, v, u, define v XOR u to be the vector whose i-th bit is u; XOR v. Say that the plaintext has x bits. For the cyphertext we randomly select a random number r with a bits, (this means that all of the 2" vectors with x bits, have probability 1/2" to be selected). For a vector u, our code message is x XOR r In a known plaintext attack how would you discover the key r