The only reason you need the BIO API is because it is the only way to push data into OpenSSL, there is no reason why this can't be done with buffers you manage.

The only reason you need the BIO API is because it is the only way to push data into OpenSSL, there is no reason why this can't be done with buffers you manage. For example: http://funcptr.net/2012/04/08/openssl-as-a-filter-(or-non-blocking-openssl)/ http://funcptr.net/2012/04/08/openssl-as-a-filter-(or-non-bl... is a blog post I wrote wherein I show how to use SSL as a filter. The only reason I use a BIO is to temporarily store the same data I just got from the network and have in an std::string... it's duplication.