We have MD5, SHA1, sha256, sha512 implemented, to use when openssl is not available. Can we do the same with sha-3?. I would suggest to adopt the reference implementation without extensive optimizations, since we will have them when openssl has them.

So we might implement SHA-3 now and integrate OpenSSL implementation later, when available. This is interesting, for instance, because many users of Python 3.4 will have a non "up to date" OpenSSL system library.