I'm not well versed in this area, but it seems that the quote along the lines of "Whatever man can hide through obfuscation, another man can uncover with sufficient intelligence, knowledge, sweat, research, time, and a good beer."

(OK, I don't have the quote handy, but that was the gist of it.)

I can't think of any absolutely secure way of distributing code that can't be reverse engineered. Sure, if the author could come around and type in a password to decrypt it, and the machine was in a known state so that keystroke grabbers and image snatchers were known not to be present, that would be PDS [Pretty Damn Secure]. Short of that (and I'm sure someone will argue with even that concession), we're all just fooling ourselves, maybe occasionally buying time through indifference, the limited resources of interested folks, and the huge number of interesting projects for those interested folks to attack.

So what do you consider secure?

Actually, you can quite trivially secure software against reverse engineering: if you have control over the hardware it runs on.

Of course, that's not much help in practice. Particularly because you cannot, by any means, do so if the hardware is not under your control.

Hence efforts like the TPM chip.

Makeshifts last the longest.

Any lock can be opened, and most locks rather trivially as well. Does that mean locks are stupid? Does that mean you never lock your car/bike/house? Just like locks, the point of "securing" source code isn't to make it 100% impossible to break it. If the cost of breaking the security is higher than the gain, then it will do.