Let F be a single round of a Feistel cipher operating on 64 bit blocks, so that inputs to it are (az, ar) where aj and ar are each 32 bits long, and F maps (az, ar) to (ap, az xor f (ar, K)). Suppose that (az, ar) and (bz,br) are a pair of plaintexts such that q = ar xor br. Consider two rounds of Feistel so that (CL, CR) = F(F (A1, ar)) and (d, dr) = F(F (b[, br)). Show that if cu = d; then Cr xor dr = q . Let F be a single round of a Feistel cipher operating on 64 bit blocks, so that inputs to it are (az, ar) where aj and ar are each 32 bits long, and F maps (az, ar) to (ap, az xor f (ar, K)). Suppose that (az, ar) and (bz,br) are a pair of plaintexts such that q = ar xor br. Consider two rounds of Feistel so that (CL, CR) = F(F (A1, ar)) and (d, dr) = F(F (b[, br)). Show that if cu = d; then Cr xor dr =