.NET: Why are names preserved in IL?...easy recfactoring tools?

pwd

If I open compiled .net assemblies I made in reflector, I can see all the original names of classes, members etc.
I don't understand why these aren't altered when the assembly is built, with optimize code selected in the configuration.

I see two obvious effects:

It makes reverse engineering easier.
It increases the filesize, which is a consideration in this case (clientside app on webpage)

Both of these effects are negative. So why does it happen like this?

fasty

By design. C# is compiled to intermediate bytecode, not machine code. Use an obfuscation tool if you want to make reverse engineering more difficult.

pwd

Yeah I know it is compiled into IL. I would have assumed that selecting the "optimize code" option would replace member names with shorter equivalents though. I was surprised to see it didn't.
Then again, I suppose in most contexts minimising filesize isn't particularly important.

fasty

I never really looked into what code optimisations are done, but I'd imagine it's things like unrolling loops and inlining as opposed to stripping out strings.

But yeah, it's not ideal...