How is the CONFIDENTIAL DELIVERY score calculated?
To evaluate this feature we focus on the establishment of trustable encrypted communication channels between the sender MTA and the recipient MTA.
How is the PHISHING and IDENTITY THEFT score calculated?
To evaluate the protection against phishing and identity theft, we focus on the usage of standards that would allow providers to publicise lists of authorized domains, as well as determine if a message received was sent from an authorized domain.
How is the INTEGRITY OF MESSAGES score calculated?
To evaluate the integrity we focus on the generation and validation of digital signatures that can be used to prove the origin of a message (which MTA sent it), and that the message has not been modified in transit.