Hook on mscorlib (System.Security.Cryptography.CryptoStream) to log parameters
See the question and my original answer on StackOverflowI think you can do it either writing a specific debugger or a specific profiler. Here is a link to the CLR Managed Debugger (mdbg) Sample 4.0 and a link to the CLR Profiler for .NET Framework 4 (sources and binaries)