QtKeychain is a Qt API to store passwords and other secret data
securely. How the data is stored on Linux:

If running, GNOME Keyring is used, otherwise qtkeychain tries to
use KWallet (via D-Bus), if available. In unsupported environments
QtKeychain will report an error. It will not store any data
unencrypted unless explicitly requested (setInsecureFallback(
true )).