Brent Rector: The Truth about Code Obfuscators

"An obfuscator only delays the inevitable. With unlimited resources (time and money) and physical access to code, all code can be reverse engineered. This was true for native x86 binaries and it's true for .NET Framework applications. What an obfuscator does is increase the cost of the effort required to reverse engineer obfuscated code. Hopefully, it increases the cost enough to make reverse engineering your code unpractical."