J. Nick Koston’s ESPHome work addresses a gap in wireless updates: the existing password authenticated the uploader, but the firmware image itself still travelled in plaintext. Someone listening on the local network could capture the Wi-Fi credentials and API encryption key embedded in that image.
A new encryption option uses the same encrypted session protocol as ESPHome’s API and makes both device and command-line client fail closed rather than accepting a downgraded plaintext upload. It is opt-in, adds nothing to builds that do not configure it, and can inherit the device’s existing API encryption key.
The matching documentation recommends encryption instead of relying on an upload password for confidentiality. jesserockz reviewed and approved both the implementation and its documentation.