def calculate_block_size
      char_amount = 1
      base_length = @oracle.encipher(DUMMY * char_amount).length
      result = nil
      (1..MAX_KNOWN_BLOCK_LENGTH).each do |length|
        new_length   = @oracle.encipher(DUMMY * char_amount).length
        if new_length > base_length
          result = new_length - base_length
          break
        end
        char_amount += 1
      end
      result
    end
def calculate_block_size
      char_amount = 1
      base_length = @oracle.encipher(DUMMY * char_amount).length
      result = nil
      (1..MAX_KNOWN_BLOCK_LENGTH).each do |length|
        new_length   = @oracle.encipher(DUMMY * char_amount).length
        if new_length > base_length
          result = new_length - base_length
          break
        end
        char_amount += 1
      end
      result
    end
calculate the block size by detecting the growth
 of the resulting ciphertext by sending messages
 which length increases by one until a change occurs