def linear_transformation(vector)
      ByteVector.new(
        vector.bit64.map do |byte8|
          small_linear_transformation(byte8)
        end.flatten
      )
    end
def linear_transformation(vector)
      ByteVector.new(
        vector.bit64.map do |byte8|
          small_linear_transformation(byte8)
        end.flatten
      )
    end
rubocop:enable Style/EachWithObject