$ brew install openssl
$ /usr/local/opt/openssl/bin/c_rehash $ export ARCHFLAGS="-arch x86_64" LDFLAGS="-L/usr/local/opt/openssl/lib" CFLAGS="-I/usr/local/opt/openssl/include" $ pip install cryptography
$ brew install openssl
$ /usr/local/opt/openssl/bin/c_rehash $ export ARCHFLAGS="-arch x86_64" LDFLAGS="-L/usr/local/opt/openssl/lib" CFLAGS="-I/usr/local/opt/openssl/include" $ pip install cryptography