Window C/C++ Crypto API Examples and tips

Question

I'm asking this question because I've spent the best part of a day trawling through msdn docs and other opaque sources for simple straightforward guidelines on how to get started with the Windows C/C++ Crypto API.

What I'd like to see is some example code, typical include paths, linking guidelines, etc, anything useful really. I know this is an imprecise question but I reckon imprecise answers are better none at all.

I'll get the ball rolling with my own meager findings...

Answer 1

There is also a lengthy example "Encryption using the Win32 Crypto API" over at the Code Project.

Answer 2

The msdn docs are here: http://msdn.microsoft.com/en-us/library/aa380252.aspx

This is the main include file: #include <wincrypt.h>

The cryptography bits are included as part of the Windows SDK, which is typically installed in %PROGRAMFILES(x86)%\Microsoft SDKs\Windows\SDKVERSION (e.g., C:\Program Files\Microsoft SDKs\Windows\v6.0A). The headers are typically in %WINDOWSSDK%\Include, and the related libraries are in %WINDOWSSDK%\Lib.

You must link to the cryptography libraries explicitly. Assuming you're in Visual Studio, you can add the reference by right clicking on the C++ project, choosing properties, and selecting Configuration Properties -> Linker on the treeview at left. You can then specify crypt32.lib in the input field on the right.

Alternately, (assuming you're using msvc++) add

#pragma comment(lib, "crypt32.lib")

to your source.

Answer 3

Here's a bunch of examples I've found....

• Example C Program: Listing the Certificates in a Store
• Example C Program: Using CryptAcquireContext
• Example C Program: Enumerating CSP Providers and Provider Types
• Example C Code for Opening Certificate Stores
• Example C Program: Sending and Receiving a Signed and Encrypted Message
• Example C Program: Signing a Hash and Verifying the Hash Signature

MSDN has these examples scattered around the docs

This website provides a good overview of the concepts along with cross-platform examples