Why you need to protect your intellectual property.

When you compile a program written for the Microsoft .NET framework, the program you provide to your users is not compiled into a native executable program, but instead is translated into something called the Common Intermediate Language instructions (CIL). CIL is half way between source code and native code, and is interpreted by the .NET framework when your program is run, rather than executed directly as machine code. Because of this, the source code of your application or library can be easily reproduced. Tools such as .NET Reflector (http://www.aisto.com/roeder/dotnet/) can reproduce source code from a compiled .NET assemblies in seconds, and in the .NET language of your choice! Clearly, commercial software distributed to end users without some form of protection is wide open to piracy and intellectual property theft.
The traditional solution to intellectual property protection in .NET is to use 'obfuscation', indeed Microsoft make an obfuscation utility available to Visual Studio 2005 Professional users.

So why is obsfucation not enough?

Obfuscation is the process of making your source code more difficult (but not impossible) for humans to understand. Obfuscation works by replacing the meaningful names you assign to classes, methods, properties and variables with meaningless ones. For example, it may replace a variable name of "counter" with "A4DF3CV89G" - to humans these obfuscated names are confusing and difficult to remember, but have no effect on the NET Framework interpreter. Note that obfuscation does nothing to the source code within your methods, so it is not protected at all by obfuscation. .NET Reactor does everything an obfuscator does, but then wraps your intellectual property in several more layers of protection, denying access to your source code to even those who are determined to steal your hard work. .NET Reactor's protection has never been cracked, something which cannot be said about obfuscators.

Industry Leading .NET Reactor Source Protection

.NET Reactor prevents decompilation by a variety of methods which convert your .NET assemblies into processes which no existing tool can decompile ( and which are also very likely to prevent decompilation by any future tool). .NET Reactor builds a native code wall between potential hackers and your .NET assemblies by producing a file which cannot be understood directly as CIL. Because the CIL in your assembly is emitted intact only at run time or design time (in a form in which the source is completely inaccessible), no tool is capable of decompiling .NET Reactor protected assemblies.

The native code wall created by .NET Reactor between the hacker and your source includes industry leading NecroBit technology, which is exclusive to .NET Reactor. .NET Reactor's protection has never been broken since the first release in 2004. These technologies make reconstruction of your source code more difficult by so many orders of magnitude that NecroBit is by far the most effective protection you can use for .NET assemblies.

In addition to industry leading intellectual property protection, .NET Reactor provides powerful options for securing you revenue stream by enforcing licensing terms with a rich variety of trialversion and full version locks.

.NET Reactor offers you an easy and reliable way to:
Secure your .NET applications and .NET libraries
Replace CIL code with native code
Perform additional layers of protection, including obfuscation
Merge assemblies, and
Protect your revenue by enforcing trial version restrictions and full version licensing terms.

Key Features Description NecroBit IL code protection .NET Reactor provides complete protection for your sensitive intellectual property by converting your .NET assemblies into unmanaged processes which cannot be understood as CIL, and which no existing tool can decompile. Hackers have no access to any intelligible form of your source. Anti ILDASM / Anti Decompiler No tool can disassemble/decompile .NET Reactor protected code. ILDASM(the Microsoft Intermediate Language disassembler) will actually report that it cannot interpret .NET Reactor protected assemblies. Application and Library support Whatever your .NET product, .NET Reactor protects it: both .NET applications (.exes) and .NET libraries (.dlls). Merging/Linking .NET Reactor can merge multiple .NET files (including debug files) into one executable(.exe) or library(.dll). Powerful Licensing System Powerful  and flexible, the .NET Reactor licensing features allow you to enforce your license conditions and protect your revenue stream by using hardware and software locks. The license manager can build trial or permanent licenses, in a matter of seconds. A fully documented software development kit (SDK), complete with examples, allows you to call the licensing system directly from your code, allowing you to create custom extensions to the licensing system. Third Party Support .NET Reactor is a mature product which has attracted third party development of add-ons. Obfuscation In addition to source protection, .NET Reactor provides thorough class, type, and variable obfuscation complemented by string encryption, use of non-printable characters in obfuscated names, and even Control Flow Obsfucation, which whilst retaining the function of the code makes it much more difficult to follow the logic flow. Compression .NET Reactor is able to compress applications and embedded files up to 50-75%. Trust We trust our product. .NET Reactor is protected by itself. .NET 1.1/2.0/3.0, Mono, CF .NET Reactor supports all .NET Framework implementations, including Compact Framework and Mono. Full Language Support .NET Reactor supports all types of managed assemblies (C#, VB.NET, C++.NET, ASP.NET, Delphi.NET, J#...). Intuitive GUI An intuitive, easy-to-operate GUI provides quick, comfortable operation. Command Line Support All features support command line invocation, and event driven invocation by Visual Studio Build Events. .NET Reactor produces the finished product in the same way you do. Fairly priced Everyone needs .NET Reactor, and .NET Reactor is priced to make ownership affordable — Compare with other products and features Further Tools / Features Further tools and features include a ShareIt Module Generator, Standalone License Generation Tool, Multi Assembly Protection, Strong Name Support, Digital Certificate Support,and even a Phone License Activation System.

The Protection System:

The Licensing System: