SChannel issue with Windows 10
<p>I have an application that uses the System.Net.Security.SslStream class to make a secure connection to a server.  On Windows 7 and Windows 8/8.1, this works fine.  On Windows 10, the call to SslStream.AuthenticateAsClient throws an exception - "AuthenticationException: A call to SSPI failed, see inner exception".  The inner exception is "Win32Exception: The Local Security Authority cannot be contacted".  This is not specific to one Windows 10 machine.  </p>

<p>I thought that it might have something to do with the length of the public key for the server certificate being 512 bits, so I created my own self-signed certificate with a 512 bit public key and tested SslStream.AuthenticateAsClient with it on the Windows 10 machine.  This worked fine.  </p>

<p>I am trying to figure out what changed in Windows 10 that is causing this to no longer work.  Looking at the log generated by System.Net and a capture from Wireshark, I see that the client receives the SERVER HELLO, CERTIFICATE, and SERVER DONE messages, and then the client closes the connection.  In the System event log, there is an error logged by SChannel - "A fatal alert was generated and sent to the remote endpoint. This may result in termination of the connection. The TLS protocol defined fatal error code is 40. The Windows SChannel error state is 813."  Apparently TLS error code 40 is a handshake failure, but I have not been able to find anything about SChannel error state 813.</p>

<p>By looking at the SSL handshake in Wireshark, I have found that the TLS_RSA_WITH_3DES_EDE_CBC_SHA cipher suite is being used.  When I connected to the test server that I created (which works with a 512 bit public key certificate), the TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA cipher suite is used.  Is there an issue with using TLS_RSA_WITH_3DES_EDE_CBC_SHA on Windows 10?</p>