Hi,
I'm trying to determine if all of the cipher suite CipherAlgorithmType types
are available when using SslStream.  By defaults only RC4 is showing up in
my SslStream.CipherSuite property, but I need some of the AES cipher suites.
As of a year ago, my understanding is that the AES types are still not
realized because the underlying Microsoft AES Cryptographic Provider was not
yet visible to .NET or SslStream.

Here is that newsgroup inquiry  from somebody - November 2005:

Question:
"I am having major problems connecting to a specific SSL-enabled server.
This server only supports AES 128 and AES 256, but the .NET 2.0 SslStream
class doesn't seem to support it (although the CipherAlgorithmType enum has
the values Aes128 and Aes256)."

Answer:
The underlying security package that System.Net uses (SSPI - a part of
Windows) currently does not support those cipher suites.
Mike Flasko - PM, System.Net & Winsock, MSFT

Is it still the case that AES is not useable from .NET and only useable via
the CryptoAPI using C++ or C?

Here is the list from the CipherAlgorithmType page, where only the last 4
are useable.
Aes The Advanced Encryption Standard (AES) algorithm.
Aes128 The Advanced Encryption Standard (AES) algorithm with a 128 bit key.
Aes192 The Advanced Encryption Standard (AES) algorithm with a 192 bit key.
Aes256 The Advanced Encryption Standard (AES) algorithm with a 256 bit key.
Des The Data Encryption Standard (DES) algorithm.
None No encryption algorithm is used.
Rc2 Rivest's Code 2 (RC2) algorithm.
Rc4 Rivest's Code 4 (RC4) algorithm.
TripleDes The Triple Data Encryption Standard (3DES) algorithm.

Is there a way to make the Microsoft AES Cryptographic Provider visable to
.NET by performing the tasks indicated in the knowledge base article 245030?

Thanks