I need to create a Windows Mobile Application (WinMo 6.x – C#) which is used to encrypt/decrypt files. However it is my duty to write the encryption algorithm which is AES-128 along with XTS as the mode of operation. RijndaelManaged just doesn’t cut it 🙁 Very much slower than DES and 3DES CryptoServiceProviders :O
I know it all depends on how good I am at writing the algorithm in the most efficient way. (And yes I my self have to write it from scratch but i can take a look @ other implementations)
Nevertheless, does writing a C++ .NET DLL to create the encryption/decryption algorithm + all the file handling and using it from C# have a significant performance advantage OVER writing the encryption algorithm + file handling in completely managed C# code?
If I use C++ .NET to create the encryption algorithm, should I use MFC Smart Device DLL or ATL? What is the difference and is there any impact on which one I choose? And can i just add a reference to the C++ DLL from C# or should I use P/Invoke?
I am fairly competent with C# than C++ but performance plays a major role as I have convinced my lecturers that AES is a very efficient cryptographic algorithm for resource constrained devices.
Thanx a bunch 🙂
Writing a “managed” program will have equal performance in C++ or C# or VB, since they all compile to IL anyway.
I don’t know, but if you write an unmanaged C++ class library and invoke it from managed C# app you may loose some performance during the p/invoke but your speed increase (from going unmanaged) may be enough to justify it. There’s an equal chance the p/invoke might cancel it out any potential performance gain from going unmanaged.
I don’t think there’s anyway to know for sure without doing it both ways and testing.