The different methods for device and user verification
Verification by confirming that we have scanned a QR code.
https://spec.matrix.org/v1.9/client-server-api/#qr-codes
Short authentication string (emoji or decimals).
https://spec.matrix.org/v1.9/client-server-api/#short-authentication-string-sas-verification
Verification by scanning a QR code that is shown by the other device.
Verification by showing a QR code which is scanned by the other device.
The different methods for device and user verification