>May I know where could I have .NET compatible VFP library? In other words, the data encrypted in VFP app can be decrypted in .NET. I tried VFPEncryption.fll, but it doesn't compatible with .NET as it doesn't allow to assign initial vector and etc.

The only way I was able to do that was to build a .NET COM component that I was able to call from VFP to encrypt or decrypt. Then, that library can also be used in .NET. So, from both environments, I was able to benefit of the same library to encrypt and decrypt. There might be other ways to achieve that from compliant libraries that can be used in both environments.