3.1.5.2 ConversationID
ConversationID hereafter refers to CONVERSATION_ID, as specified in section 2.2.2, as a GUID that MUST be used by both the initiator and the acceptor to maintain protocol state. The CONVERSATION_ID is a random, cryptographic-strength 16-byte value generated by the initiator and is used to set the MESSAGE_HEADER structure ConversationId field to that value, as specified in section 2.2.6.2. The ConversationID in subsequent NEGOEX messages MUST remain the same for the duration of the exchange.