enh: topics clarified

Author: Maxim Kochukov

setup.py

@@ -17,13 +17,15 @@
         'Development Status :: 3 - Alpha',
         # Chose either "3 - Alpha", "4 - Beta" or "5 - Production/Stable" as the current state of your package
         'Intended Audience :: Developers',  # Define that your audience are developers
-        'TOPIC :: SECURITY :: CRYPTOGRAPHY',
+        'Topic :: Security',
+        'Topic :: Security :: Cryptography',
         'License :: OSI Approved :: MIT License',  # Again, pick a license
         'Programming Language :: Python :: 3',  # Specify which pyhton versions that you want to support
         'Programming Language :: Python :: 3.3',
         'Programming Language :: Python :: 3.4',
         'Programming Language :: Python :: 3.5',
         'Programming Language :: Python :: 3.6',
         'Programming Language :: Python :: 3.7',
+        'Python :: Implementation :: CPython',
     ],
 )