How can I protect my NET assemblies from decompilation

Question

One if the first things I learned when I started with C  was the most important one  You can decompile any  NET assembly with Reflector or other tools  Many developers are not aware of this fact and most of them are shocked when I show them their source code   Protection against decompilation is still a difficult task  I am still looking for a fast  easy and secure way to do it  I don t want to obfuscate my code so my method names will be a b c or so  Reflector or other tools should be unable to recognize my application as  NET assembly at all  I know about some tools already but they are very expensive  Is there any other way to protect my applications   EDIT   The reason for my question is not to prevent piracy  I only want to stop competitors from reading my code  I know they will and they already did  They even told me so  Maybe I am a bit paranoid but business rivals reading my code doesn t make me feel good

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I ve heard about some projects that directly compile IL into native code  You can get some additional info from this post  Is it possible to compile  NET IL code to machine code

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At work here we use Dotfuscator from PreEmptive Solutions   Although it s impossible to protect  NET assemblies 100  Dotfuscator makes it hard enough I think  I comes with a lot of obfuscation techniques   Cross Assembly Renaming Renaming Schemes Renaming Prefix Enhanced Overload Induction Incremental Obfuscation HTML Renaming Report Control Flow String Encryption   And it turned out that they re not very expensive for small companies  They have a special pricing for small companies     No I m not working for PreEmptive  -     There are freeware alternatives of course

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We use  SmartAssembly  for  NET protection of an enterprise level distributed application  and it has worked great for us

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If someone has to steal your code  it likely means your business model is not working   What do I mean by that   For example  I buy your product and then I ask for support   You re too busy or believe my request is not valid and a waste of your time   I decode your product in order to support my relative business   Your product becomes more valuable to me and I prioritize my time in a way to resolve the business model for leveraging your product   I recode and re-brand your product and then go out and make the money that you decided to leave on the table   There are reasons for protecting code  but most likely you are looking at the problem from the wrong perspective   Of course you are   You re the  coder   and I m the business man    -   Cheers   ps   I m also a developer   i e   coder

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One thing to keep in mind is that you want to do this in a way that makes business sense  To do that  you need to define your goals  So  exactly what are your goals     Preventing piracy  That goal is not achievable  Even native code can be decompiled or cracked  the multitude of warez available online  even for products like Windows and Photoshop  is proof a determined hacker can always gain access   If you can t prevent piracy  then how about merely reducing it  This  too  is misguided  It only takes one person cracking your code for it to be available to everyone  You have to be lucky every time  The pirates only have to be lucky once     I put it to you the goal should be to maximize profits  You appear to believe that stopping piracy is necessary to this endeavor  It is not  Profit is simply revenue minus costs  Stopping piracy increases costs  It takes effort  which means adding cost somewhere in the process  and so reduces that side of the equation  Protecting your product also fails to increase your revenue  I know you look at all those pirates and see all the money you could make if only they would pay your license fees instead  but the reality is this will never happen  There is some hyperbole here  but it generally holds that pirates who are unable to crack your security will either find a similar product they can crack or do without  They will never buy it instead  and therefore they do not represent lost sales   Additionally  securing your product actually reduces revenue  There are two reasons for this  One is the small percentage of customers who have trouble with your activation or security  and therefore decide not to buy again or ask for their money back  The other is the small percentage of people who actually try a pirated version of software to make sure it works before buying  Limiting the pirated distribution of your product  if you are somehow able to succeed at this  prevents these people from ever trying your product  and so they will never buy it  Moreover  piracy can also help your product spread to a wider audience  thus reaching more people who will be willing to pay for it   A better strategy is to assume that your product will be pirated  and think about ways to take advantage of the situation  A couple more links on the topic  How do i prevent my code from being stolen  Securing a  NET Application

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If you want to fully protect your app from decompilation  look at Aladdin s Hasp  You can wrap your assemblies in an encrypted shell that can only be accessed by your application  Of course one wonders how they re able to do this but it works  I don t know however if they protect your app from runtime attachment reflection which is what Crack NET is able to do    -- Edit Also be careful of compiling to native code as a solution   there are decompilers for native code as well

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Besides the third party products listed here  there is another one  NetLib Encryptionizer  However it works in a different way than the obfuscators  Obfuscators modify the assembly itself with a deobfuscation  engine  built into it  Encryptionizer encrypts the DLLs  Managed or Unmanaged  at the file level  So it does not modify the DLL except to encrypt it  The  engine  in this case is a kernel mode driver that sits between your application and the operating system   Disclaimer  I am from NetLib Security

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Do you API   Instead of trying to protect your one ddl file in one of your products on all of your customers devices  why not create an API service for your precious product features  Let the actual product that is saved on a device consume that API to deliver the product as you want it   I Think this way you are 100  sure that your code is not decompiled and you set your own limits in your API so that developers   hackers don t consume your API in a way you don t want it   Sure is  some more work  but in the end  you are in control

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Host your service in any cloud service provider

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How to preventing decompilation of any C  application  Pretty much describes the entire situation   At some point the code will have to be translated to VM bytecode  and the user can get at it then   Machine code isn t that much different either   A good interactive disassembler debugger like IDA Pro  makes just about any native application transparent   The debugger is smart enough to use AI to identify common APIs  compiler optimizations  etc   it allows the user to meticuloulsy rebuild higher level constructs from the assembly generated from machine code   And IDA Pro supports  Net to some extent too   Honestly  after working on an reverse engineering   for compatibility   project for a few years  the main thing I got out of my experience is that I probably shouldn t worry too much about people stealing my code   If anyone wants it  it will never be very hard to get it no matter what scheme I implement

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I know this is old but  Themida is the most advanced anti-cracking software I ve ever used  It s not free  though

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I know you don t want to obfuscate  but maybe you should check out dotfuscator  it will take your compiled assemblies and obfuscate them for you   I think it can even encrypt them

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No obsfuscator can protect your application  not even any one described here  See this link  it s an deobsfuscator which can deobsfuscate almost every obsfuscator out there   https   github com 0xd4d de4dot  The best way which can help you  but remember that they are also not full prof  is to use mixed codes  code your important codes in unmanaged language and make a DLL like in C or C   and then protect them either with Armageddon or Themida  Themida is not for every cracker  it s one of the best protector in the market  it can also protect your  NET software

[c#] How can I protect my .NET assemblies from decompilation?

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