If you read closer, you will see that you need "special permission from RSADSI" to use non-published interfaces to RSAREF.

I thought their interface was good enough to do all of the obvious operations -- RSA block encrypt and decrypt being the most important -- and that this restriction was just to prevent bizarrelly hacked versions of their code from being confused with the original.

R_SignPEMBlock computes a digital signature on a message R_VerifyBlockSignature verifies a digital signature on a block of data such as a certificate

Let me know if I'm wrong, but I don't think I am. -- Marc Ringuette (mnr@cs.cmu.edu)