Office 365 Exchange encryption

hi,

Can anyone explain how to verify encryption on email environment? We are running on Hybrid/O365 (have internal exchange mail server + office 365 cloud service). When I ctrl+right click on outlook icon and go to Connection status I can see SSL under encryption. When I check encryption cert public key is RSA 2048 for Office 365. Does it mean we use SSL (internal) + TLS (office 365) ?

MK