Q4. Consider the following cipher that uses the following table and product cipher (substitution and transposition): To encrypt a message: 1. 2. 3. 4. Using the table to substitute a letter with two letters (The header of the raw and the header of the column) Divide the result into two halves and then place the second half below the first. Form pairs of letters the letter from the first row and the second is the one below it. Transform the pairs using the table. Encrypt the message: computer" a. All A | B DIE b. Decrypt the Ciphertext: "RYEANCCVKOAUPXKYXW