x6: Add req and provide skeleton

x6.md

@@ -11,6 +11,50 @@ updated: 2019-04-22
 **TODO: Specify conversational security and guarantees**
 
 *NOTE: Starting point: PFS whitepaper.*
+## Introduction
+
+## Requirements
+
+TODO: Elaborate on Whisper as a requirement in more detail, to such an extent that another transport layer could also fit it.
+
+## Design goals
+
+TODO: Fill in design goals. This is somewhat filled in below, but there are other requirements such as a selecton of the following:
+
+Security and Privacy
+
+Confidentiality
+Integrity
+Authentication
+Participant Consistency
+Destination Validation
+Forward Secrecy
+Backward Secrecy
+Anonymity Preserving
+Speaker Consistency
+Causality Preserving
+Global Transcript
+Message Unlinkability
+Message Repudiation
+Particip. Repudiation
+Adoption
+
+Out-of-Order Resilient
+Dropped Message Resilient
+Asynchronicity
+Multi-Device Support
+No Additional Service
+Group chat
+
+Computational Equality
+Trust Equality
+Subgroup Messaging
+Contractable
+Expandable
+
+That should be expanded on. See end of document for more
+
+# Below is import form previous best documentation
 
 Status Perfect Forward Secrecy Whitepaper
 ====