<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><span style="font-family: HelveticaNeue;" class="">The openssl api documentations mentions this about using the low-level implementations.</span><br style="font-family: HelveticaNeue;" class=""><br style="font-family: HelveticaNeue;" class=""><font face="HelveticaNeue" class="">"Although low level algorithm specific functions exist for many algorithms their use is discouraged. They cannot be used with an ENGINE and ENGINE versions of new algorithms cannot be accessed using the low level functions. Also makes code harder to adapt to new algorithms and some options are not cleanly supported at the low level and some operations are more efficient using the high level interface.”</font><br style="font-family: HelveticaNeue;" class=""><br style="font-family: HelveticaNeue;" class=""><span style="font-family: HelveticaNeue;" class="">and</span><br style="font-family: HelveticaNeue;" class=""><br style="font-family: HelveticaNeue;" class=""><span style="font-family: HelveticaNeue;" class="">"All the symmetric algorithms (ciphers), digests and asymmetric algorithms (public key algorithms) can be replaced by ENGINE modules providing alternative implementations. If ENGINE implementations of ciphers or digests are registered as defaults, then the various EVP functions will automatically use those implementations automatically in preference to built in software implementations. For more information, consult the engine(3) man page.”</span><br style="font-family: HelveticaNeue;" class=""><br style="font-family: HelveticaNeue;" class=""><span style="font-family: HelveticaNeue;" class="">AES-NI for openssl is an engine implementation, another example is VIA padlock or specialized hardware boards.</span><br style="font-family: HelveticaNeue;" class=""><br style="font-family: HelveticaNeue;" class=""><span style="font-family: HelveticaNeue;" class="">By using the evp “envelope” layer of openssl you can use all available ciphers in openssl and its engine implementations without adding new nif functions. </span><div class=""><span style="font-family: HelveticaNeue;" class=""><br class=""></span></div><div class=""><span style="font-family: HelveticaNeue;" class="">To me that seems the most logical way to handle things.</span></div></body></html>