To use the PassiveTotal API, you need to first create a free account on their website. Once you are logged in, you can view your API key by navigating to your account settings and clicking on the User Show button under the API ACCESS section. See the following screenshot for a visual representation of this page.

All libraries used in this script are present in Python's standard library. However, we do install the PassiveTotal Python API client and follow the installation and setup instructions in the README found at https://github.com/passivetotal/python_api or with pip install passivetotal==1.0.30. We do this to use the PassiveTotal command-line pt-client application. In this script, we make the API calls through this client rather than performing this at a more manual level as we did in the previous recipe. More details on the PassiveTotal API, especially if you are interested in developing something more advanced, can be found on their website.