> When writing in a higher language such as e.g. C, you can use code obfuscators to make your C code extremely hard to read.

Obfuscating C code shouldn't have any bearing on the decompilability of the output.

> If you want to make it (virtually) impossible to even disassemble the machine code, you could encrypt your binary itself except for a small bootstrap that will unencrypt the remainder of the binary when it runs.

Unencrypting the binary at startup is somewhat easy to hook into. It's harder to decrypt each individual function when that function is called and then re-encrypt it after the function ends. Bonus points if you re-encrypt after each `CALL`.

This is stuff which was available back in 2003 -- that's when I first used techniques.