private byte[] makeHeader(int number) {
		byte[] header = new byte[HEADER_SIZE];
		if(number >= (1 << (8* HEADER_SIZE))) {
			throw new InputMismatchException("The round number " + number + " exceeds the bound of " + (1 << (8*HEADER_SIZE)));
		}
		int i = 0;
		do {
			header[i] = (byte) (number % 256);
			number >>= 8;
			i++;
		} while(number != 0);
		return header;
	}