gf2MatrixSquare(even, odd)
		if len2&1 != 0 {
			crc1n = gf2MatrixTimes(even, crc1n)
		}
		len2 >>= 1

		// if no more bits set, then done
		if len2 == 0 {
			break
		}

		// another iteration of the loop with odd and even swapped
		gf2MatrixSquare(odd, even)
		if len2&1 != 0 {
			crc1n = gf2MatrixTimes(odd, crc1n)
		}
		len2 >>= 1

		// if no more bits set, then done