I need more details on Open SSL engine in terms of flow, essential APIs
to be supported in my own engine if I need to write one. I looked at
the OpenSSL engine source (e.g. e_cswit.c). I see lot of code for RSA,
DSA, DH etc. but don't see any HASH related/relevant code. Why hashing
is not part of engine? I will have some more question(s) as I explore
more. Any help/pointer in this regard would be greatly appreciated.