I found this guide to the Windows CryptoAPI: http://www.apress.com/article/articl...ay.html?aID=12

CryptoAPI is included in the MS OS' (98, ME, 2000 & XP) and with it you can use the most common cryptography providers, like DSS, RSA, Diffie-Hellmann and more. It lets you handle public/private keys, hashing, signing of data and encryption/decryption.

The article explains the CryptoAPI using Visual Basic examples, but the CryptoAPI can easily be used in Visual C++ also.

I find this article very helpful as the CryptoAPI's documentation on MSDN lacks an easy-to-understand walkthrough.

Last, here's a little tip: If you don't want to dig into the difficult CryptoAPI, Microsoft has created an easy-to-use wrapper around CryptoAPI called CAPICOM . With it you can basically do the same things as with CryptoAPI, but with a few limitations. Information about CAPICOM can be found here: http://msdn.microsoft.com/library/de..._reference.asp