5.4.2.3 Changes to the Security Commencement Phase

If Standard RDP Security mechanisms are not being used in conjunction with an External Security protocol (that is, the selected Encryption Level described in section 5.3.2 is ENCRYPTION_LEVEL_NONE (0)), then the Security Commencement phase of the RDP Connection Sequence (section 1.3.1.1) is not executed, with the result that the client does not send the Security Exchange PDU (section 2.2.1.10). This PDU can be dropped because the Client Random is redundant in this case because encryption for the connection is only provided by the External Security Protocol (section 5.4.5).