public static boolean allZeros(byte[] buf) {
        return Arrays.areAllZeroes(buf, 0, buf.length);
    }
@Test
    void all_zeros_checks_length_and_array_contents() {
        assertTrue(SideChannelSafe.allZeros(new byte[0]));
        assertFalse(SideChannelSafe.allZeros(new byte[]{ 1 }));
        assertTrue(SideChannelSafe.allZeros(new byte[]{ 0 }));
        assertFalse(SideChannelSafe.allZeros(new byte[]{ 0, 0, 127, 0 }));
        assertFalse(SideChannelSafe.allZeros(new byte[]{ 0, 0, -1, 0 }));
        assertTrue(SideChannelSafe.allZeros(new byte[]{ 0, 0, 0 }));
    }