.NET 4.5 WIF and SAML x509 certificate encryption

I am looking for a WIF .NET 4.5 code sample that shows how to verify a signature and decrypt a SAML request.  Here is the basic flow of what I am looking to do. 

1. Decode the text in base-64 format

2. Verify the signature in the Signature tag

3. Decrypt the first CipherData using private key.

4. Decrypt the second cipherdata using the key obtained in step 3.

Any samples that do this in WIF .NET 4.5 would be helpful.