5.4.5.1 Transport Layer Security (TLS)
TLS 1.0, 1.1, 1.2, and 1.3 are represented by the PROTOCOL_SSL (0x00000001) flag in the RDP Negotiation Request (section 2.2.1.1.1) and RDP Negotiation Response (section 2.2.1.2.1) structures. TLS is derived from SSL ([SSL3]) and was added to RDP to enable authentication of the remote computer's identity, hence mitigating man-in-the-middle attacks on RDP traffic.<56>