I found a link that explains what CAPICOM does for 3DES (Understanding Capicom), but I'm not sure if this is directly applicable to the single DES algorithm that CAPICOM does.
It seems that CAPICOM does some proprietary stuff to derive the actual key it uses to encrypt. It also puts a lot of header information in front of the encrypted data for it's own use (OIDs for the library, the IV, the salt). So the results of a DES or 3DES encrypted value from CAPICOM is not directly compatible with System.Security.Cryptography nor is it documented. The link I gave above explains the process for deriving the key for 3DES, but it seems to not work with single DES.
Does anyone know how CAPICOM derives the actual key when it encrypts data with single DES?
Any help or ideas is appreciated. I'll be trying to see if I can get anything to work, but not sure how much time I can devote to this.
EDIT: for clarity