Which library on windows is used to encrypt and decrypt messages while using TLS/SSL?

I wish to write a small IM client. If you can also provid开发者_StackOverflowe links to some literature/sample code that would be great.

If you're writing native code, you're probably going to want to look at SSPI and specifially SChannel:

The Schannel security package provides access to four security protocols:

• Transport Layer Security (TLS 1.2)
• Transport Layer Security (TLS 1.1)
• Transport Layer Security (TLS 1.0)
• Secure Sockets Layer (SSL 3.0)
• Secure Sockets Layer (SSL 2.0)

Let's ignore for the moment that they can't count :-)

Depending on the language / platform (.NET, Win32 API etc.) there are several options available.

SChannel has been mentioned above. Then you can use OpenSSL. Also depending on your platform you can use our SSLBlackbox.