I have a console application references assembly A. I want to ensure that the application will not run if A.dll is tampered or replaced.
One option is to use strong-name signing. But do I need to worry about strong name bypass?
Are there any other good options?
Thanks
If you can build the protection, a hacker can break it. Don't worry too much about preventing tampering, the guys who can break it in a heartbeat probably won't care, and even if they did, almost nothing you could do would deter them.
The best advice would be to license a product that's built by a team specifically for the purpose of protecting your applications in this way. Just like with cryptography, it's usually best not to roll your own.
According to the author of that page:
Instead, for integrety checking, you really need to use Authenticode signatures.
What you need is products like www.red-gate.com/products/smartassembly/ , and there're plenty of such products. However, they only protect your assembly to certain extent, none is 100% safe.
Do what web browsers do and rely on a certificate from a trusted third party.
You can use an MD5 hash of your dll, but even that's not terribly foolproof because anyone who wants to break your app will just use a reflector and find out what you're really doing and probably just modify your program straight-up. You can get code obfuscators that will help with that, but nothing is perfectly hack-proof. It's really a trade off - what is your value of preventing someone from changing your dll? What is the likelihood that someone will? and how much will it cost you in terms of time = money to protect against that?
Actually, do not even try to anyhow defend your code / assembly, or whatever else. I mean, if it is possible (and it is designed) to be run on a computer, for public and such, it is impossible to protect it - you can do WHATEVER you want on your own computer, with good tools and such you deassemble it in a second.
So, don't try, you will just waste your time.