diff --git a/diagrams/message.mmd b/diagrams/message.mmd
index 94ea8e7bbc..16e67c198d 100644
--- a/diagrams/message.mmd
+++ b/diagrams/message.mmd
@@ -1,12 +1,17 @@
 sequenceDiagram
   participant Alice
-  participant App A
-  participant Server A
-  participant Server B
-  participant App B
+  participant App A as Alice's app
+  participant Server A as Alice's server
+  participant Server B as Bob's server
+  participant App B as Bob's app
   participant Bob
-  Alice ->> App A: Alice writes the message to Bob in the app
-  App A ->> Server A: The message (including ID & timestamp) is encrypted with Bob's <BA public key> and sent to all Alice's servers<br>{from: <AB public key hash>, to: <BA public key hash>, message: <encrypted with BA public key>}
-  Server A ->> Server B: Alice's servers use <BA public key hash> to locate Bob's servers<br>and forward encrypted message to all Bob's servers (when they are different from Alice's servers)
+  Alice -->> App A: Alice writes the message to Bob in the app
+  App A ->> Server B: The message (including msg ID & timestamp) is signed with <AB private key>, encrypted with Bob's <BA public key> and sent to Bob's servers<br>{to: <BA public key hash>, message: <encrypted with BA public key>} (also signed/encrypted with <A_BA server private/public keys>)
   Server B ->> App B: Bob's servers send the message to Bob's app
-  App B ->> Bob: Bob's app uses <AB public key hash> to identify Alice<br>and decrypts the messages with Bob's <BA private key>
+  App B -->> Bob: Bob's app uses <BA public key hash> to identify Alice<br>and decrypts the messages with Bob's <BA private key>
+
+  Note over App B: App creates<br>"message received"<br>including:<br>- msg correlation ID<br>- timestamp
+
+  App B ->> Server A: "message received" signed with <BA private key>, encrypted with Alice's <AB public key><br>{to: <AB public key hash>, message: <encrypted with AB public key>} (also signed/encrypted with <B_AB server private/public keys>)
+  Server A ->> App A: "message received": Alice's app uses <AB public key hash> to identify Bob<br>and decrypts "message received" with Alice's <AB private key>
+  App A -->> Alice: "message received" shown to Alice
diff --git a/diagrams/message.svg b/diagrams/message.svg
index 46a6fe2540..a04d996dd0 100644
--- a/diagrams/message.svg
+++ b/diagrams/message.svg
@@ -1,49 +1,49 @@
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+#mermaid-1576967608788 .stateGroup .composit {
   fill: white;
   border-bottom: 1px; }
 
-#mermaid-1576939215542 .stateGroup .alt-composit {
+#mermaid-1576967608788 .stateGroup .alt-composit {
   fill: #e0e0e0;
   border-bottom: 1px; }
 
-#mermaid-1576939215542 .state-note {
+#mermaid-1576967608788 .state-note {
   stroke: #aaaa33;
   fill: #fff5ad; }
-#mermaid-1576939215542   .state-note text {
+#mermaid-1576967608788   .state-note text {
     fill: black;
     stroke: none;
     font-size: 10px; }
 
-#mermaid-1576939215542 .stateLabel .box {
+#mermaid-1576967608788 .stateLabel .box {
   stroke: none;
   stroke-width: 0;
   fill: #ECECFF;
   opacity: 0.5; }
 
-#mermaid-1576939215542 .stateLabel text {
+#mermaid-1576967608788 .stateLabel text {
   fill: black;
   font-size: 10px;
   font-weight: bold;
@@ -492,7 +492,7 @@
   --mermaid-font-family: '"trebuchet ms", verdana, arial';
   --mermaid-font-family: "Comic Sans MS", "Comic Sans", cursive; }
 
-:root { --mermaid-font-family: "trebuchet ms", verdana, arial;}</style><style>#mermaid-1576939215542 {
+:root { --mermaid-font-family: "trebuchet ms", verdana, arial;}</style><style>#mermaid-1576967608788 {
     color: rgb(0, 0, 0);
     font: normal normal 400 normal 16px / normal "trebuchet ms", verdana, arial;
-  }</style><g></g><g><line id="actor1836" x1="75" y1="5" x2="75" y2="325" class="actor-line" stroke-width="0.5px" stroke="#999"></line><rect x="0" y="0" fill="#eaeaea" stroke="#666" width="150" height="65" rx="3" ry="3" class="actor"></rect><text x="75" y="32.5" dominant-baseline="central" alignment-baseline="central" class="actor" style="text-anchor: middle; font-size: 14px;"><tspan x="75" dy="0">Alice</tspan></text></g><g><line id="actor1837" x1="275" y1="5" x2="275" y2="325" class="actor-line" stroke-width="0.5px" stroke="#999"></line><rect x="200" y="0" fill="#eaeaea" stroke="#666" width="150" height="65" rx="3" ry="3" class="actor"></rect><text x="275" y="32.5" dominant-baseline="central" alignment-baseline="central" class="actor" style="text-anchor: middle; font-size: 14px;"><tspan x="275" dy="0">App A</tspan></text></g><g><line id="actor1838" x1="475" y1="5" x2="475" y2="325" class="actor-line" stroke-width="0.5px" stroke="#999"></line><rect x="400" y="0" fill="#eaeaea" stroke="#666" width="150" height="65" rx="3" ry="3" class="actor"></rect><text x="475" y="32.5" dominant-baseline="central" alignment-baseline="central" class="actor" style="text-anchor: middle; font-size: 14px;"><tspan x="475" dy="0">Server A</tspan></text></g><g><line id="actor1839" x1="675" y1="5" x2="675" y2="325" class="actor-line" stroke-width="0.5px" stroke="#999"></line><rect x="600" y="0" fill="#eaeaea" stroke="#666" width="150" height="65" rx="3" ry="3" class="actor"></rect><text x="675" y="32.5" dominant-baseline="central" alignment-baseline="central" class="actor" style="text-anchor: middle; font-size: 14px;"><tspan x="675" dy="0">Server B</tspan></text></g><g><line id="actor1840" x1="875" y1="5" x2="875" y2="325" class="actor-line" stroke-width="0.5px" stroke="#999"></line><rect x="800" y="0" fill="#eaeaea" stroke="#666" width="150" height="65" rx="3" ry="3" class="actor"></rect><text x="875" y="32.5" dominant-baseline="central" alignment-baseline="central" class="actor" style="text-anchor: middle; font-size: 14px;"><tspan x="875" dy="0">App B</tspan></text></g><g><line id="actor1841" x1="1075" y1="5" x2="1075" y2="325" class="actor-line" stroke-width="0.5px" stroke="#999"></line><rect x="1000" y="0" fill="#eaeaea" stroke="#666" width="150" height="65" rx="3" ry="3" class="actor"></rect><text x="1075" y="32.5" dominant-baseline="central" alignment-baseline="central" class="actor" style="text-anchor: middle; font-size: 14px;"><tspan x="1075" dy="0">Bob</tspan></text></g><defs><marker id="arrowhead" refX="5" refY="2" markerWidth="6" markerHeight="4" orient="auto"><path d="M 0,0 V 4 L6,2 Z"></path></marker></defs><defs><marker id="crosshead" markerWidth="15" markerHeight="8" orient="auto" refX="16" refY="4"><path fill="black" stroke="#000000" stroke-width="1px" d="M 9,2 V 6 L16,4 Z" style="stroke-dasharray: 0, 0;"></path><path fill="none" stroke="#000000" stroke-width="1px" d="M 0,1 L 6,7 M 6,1 L 0,7" style="stroke-dasharray: 0, 0;"></path></marker></defs><defs><marker id="sequencenumber" refX="15" refY="15" markerWidth="60" markerHeight="40" orient="auto"><circle cx="15" cy="15" r="6"></circle></marker></defs><g><text x="175" y="93" class="messageText" style="text-anchor: middle;">Alice writes the message to Bob in the app</text><line x1="75" y1="100" x2="275" y2="100" class="messageLine0" stroke-width="2" stroke="black" marker-end="url(#arrowhead)" style="fill: none;"></line></g><g><text x="375" y="128" class="messageText" style="text-anchor: middle;">The message (including ID &amp; timestamp) is encrypted with Bob's &lt;BA public key&gt; and sent to all Alice's servers</text><text x="375" y="145" class="messageText" style="text-anchor: middle;">{from: &lt;AB public key hash&gt;, to: &lt;BA public key hash&gt;, message: &lt;encrypted with BA public key&gt;}</text><line x1="275" y1="135" x2="475" y2="135" class="messageLine0" stroke-width="2" stroke="black" marker-end="url(#arrowhead)" style="fill: none;"></line></g><g><text x="575" y="163" class="messageText" style="text-anchor: middle;">Alice's servers use &lt;BA public key hash&gt; to locate Bob's servers</text><text x="575" y="180" class="messageText" style="text-anchor: middle;">and forward encrypted message to all Bob's servers (when they are different from Alice's servers)</text><line x1="475" y1="170" x2="675" y2="170" class="messageLine0" stroke-width="2" stroke="black" marker-end="url(#arrowhead)" style="fill: none;"></line></g><g><text x="775" y="198" class="messageText" style="text-anchor: middle;">Bob's servers send the message to Bob's app</text><line x1="675" y1="205" x2="875" y2="205" class="messageLine0" stroke-width="2" stroke="black" marker-end="url(#arrowhead)" style="fill: none;"></line></g><g><text x="975" y="233" class="messageText" style="text-anchor: middle;">Bob's app uses &lt;AB public key hash&gt; to identify Alice</text><text x="975" y="250" class="messageText" style="text-anchor: middle;">and decrypts the messages with Bob's &lt;BA private key&gt;</text><line x1="875" y1="240" x2="1075" y2="240" class="messageLine0" stroke-width="2" stroke="black" marker-end="url(#arrowhead)" style="fill: none;"></line></g><g><rect x="0" y="260" fill="#eaeaea" stroke="#666" width="150" height="65" rx="3" ry="3" class="actor"></rect><text x="75" y="292.5" dominant-baseline="central" alignment-baseline="central" class="actor" style="text-anchor: middle; font-size: 14px;"><tspan x="75" dy="0">Alice</tspan></text></g><g><rect x="200" y="260" fill="#eaeaea" stroke="#666" width="150" height="65" rx="3" ry="3" class="actor"></rect><text x="275" y="292.5" dominant-baseline="central" alignment-baseline="central" class="actor" style="text-anchor: middle; font-size: 14px;"><tspan x="275" dy="0">App A</tspan></text></g><g><rect x="400" y="260" fill="#eaeaea" stroke="#666" width="150" height="65" rx="3" ry="3" class="actor"></rect><text x="475" y="292.5" dominant-baseline="central" alignment-baseline="central" class="actor" style="text-anchor: middle; font-size: 14px;"><tspan x="475" dy="0">Server A</tspan></text></g><g><rect x="600" y="260" fill="#eaeaea" stroke="#666" width="150" height="65" rx="3" ry="3" class="actor"></rect><text x="675" y="292.5" dominant-baseline="central" alignment-baseline="central" class="actor" style="text-anchor: middle; font-size: 14px;"><tspan x="675" dy="0">Server B</tspan></text></g><g><rect x="800" y="260" fill="#eaeaea" stroke="#666" width="150" height="65" rx="3" ry="3" class="actor"></rect><text x="875" y="292.5" dominant-baseline="central" alignment-baseline="central" class="actor" style="text-anchor: middle; font-size: 14px;"><tspan x="875" dy="0">App B</tspan></text></g><g><rect x="1000" y="260" fill="#eaeaea" stroke="#666" width="150" height="65" rx="3" ry="3" class="actor"></rect><text x="1075" y="292.5" dominant-baseline="central" alignment-baseline="central" class="actor" style="text-anchor: middle; font-size: 14px;"><tspan x="1075" dy="0">Bob</tspan></text></g></svg>
\ No newline at end of file
+  }</style><g></g><g><line id="actor9090" x1="75" y1="5" x2="75" y2="505" class="actor-line" stroke-width="0.5px" stroke="#999"></line><rect x="0" y="0" fill="#eaeaea" stroke="#666" width="150" height="65" rx="3" ry="3" class="actor"></rect><text x="75" y="32.5" dominant-baseline="central" alignment-baseline="central" class="actor" style="text-anchor: middle; font-size: 14px;"><tspan x="75" dy="0">Alice</tspan></text></g><g><line id="actor9091" x1="275" y1="5" x2="275" y2="505" class="actor-line" stroke-width="0.5px" stroke="#999"></line><rect x="200" y="0" fill="#eaeaea" stroke="#666" width="150" height="65" rx="3" ry="3" class="actor"></rect><text x="275" y="32.5" dominant-baseline="central" alignment-baseline="central" class="actor" style="text-anchor: middle; font-size: 14px;"><tspan x="275" dy="0">Alice's app</tspan></text></g><g><line id="actor9092" x1="475" y1="5" x2="475" y2="505" class="actor-line" stroke-width="0.5px" stroke="#999"></line><rect x="400" y="0" fill="#eaeaea" stroke="#666" width="150" height="65" rx="3" ry="3" class="actor"></rect><text x="475" y="32.5" dominant-baseline="central" alignment-baseline="central" class="actor" style="text-anchor: middle; font-size: 14px;"><tspan x="475" dy="0">Alice's server</tspan></text></g><g><line id="actor9093" x1="675" y1="5" x2="675" y2="505" class="actor-line" stroke-width="0.5px" stroke="#999"></line><rect x="600" y="0" fill="#eaeaea" stroke="#666" width="150" height="65" rx="3" ry="3" class="actor"></rect><text x="675" y="32.5" dominant-baseline="central" alignment-baseline="central" class="actor" style="text-anchor: middle; font-size: 14px;"><tspan x="675" dy="0">Bob's server</tspan></text></g><g><line id="actor9094" x1="875" y1="5" x2="875" y2="505" class="actor-line" stroke-width="0.5px" stroke="#999"></line><rect x="800" y="0" fill="#eaeaea" stroke="#666" width="150" height="65" rx="3" ry="3" class="actor"></rect><text x="875" y="32.5" dominant-baseline="central" alignment-baseline="central" class="actor" style="text-anchor: middle; font-size: 14px;"><tspan x="875" dy="0">Bob's app</tspan></text></g><g><line id="actor9095" x1="1075" y1="5" x2="1075" y2="505" class="actor-line" stroke-width="0.5px" stroke="#999"></line><rect x="1000" y="0" fill="#eaeaea" stroke="#666" width="150" height="65" rx="3" ry="3" class="actor"></rect><text x="1075" y="32.5" dominant-baseline="central" alignment-baseline="central" class="actor" style="text-anchor: middle; font-size: 14px;"><tspan x="1075" dy="0">Bob</tspan></text></g><defs><marker id="arrowhead" refX="5" refY="2" markerWidth="6" markerHeight="4" orient="auto"><path d="M 0,0 V 4 L6,2 Z"></path></marker></defs><defs><marker id="crosshead" markerWidth="15" markerHeight="8" orient="auto" refX="16" refY="4"><path fill="black" stroke="#000000" stroke-width="1px" d="M 9,2 V 6 L16,4 Z" style="stroke-dasharray: 0, 0;"></path><path fill="none" stroke="#000000" stroke-width="1px" d="M 0,1 L 6,7 M 6,1 L 0,7" style="stroke-dasharray: 0, 0;"></path></marker></defs><defs><marker id="sequencenumber" refX="15" refY="15" markerWidth="60" markerHeight="40" orient="auto"><circle cx="15" cy="15" r="6"></circle></marker></defs><g><text x="175" y="93" class="messageText" style="text-anchor: middle;">Alice writes the message to Bob in the app</text><line x1="75" y1="100" x2="275" y2="100" class="messageLine1" stroke-width="2" stroke="black" marker-end="url(#arrowhead)" style="stroke-dasharray: 3, 3; fill: none;"></line></g><g><text x="475" y="128" class="messageText" style="text-anchor: middle;">The message (including msg ID &amp; timestamp) is signed with &lt;AB private key&gt;, encrypted with Bob's &lt;BA public key&gt; and sent to Bob's servers</text><text x="475" y="145" class="messageText" style="text-anchor: middle;">{to: &lt;BA public key hash&gt;, message: &lt;encrypted with BA public key&gt;} (also signed/encrypted with &lt;A_BA server private/public keys&gt;)</text><line x1="275" y1="135" x2="675" y2="135" class="messageLine0" stroke-width="2" stroke="black" marker-end="url(#arrowhead)" style="fill: none;"></line></g><g><text x="775" y="163" class="messageText" style="text-anchor: middle;">Bob's servers send the message to Bob's app</text><line x1="675" y1="170" x2="875" y2="170" class="messageLine0" stroke-width="2" stroke="black" marker-end="url(#arrowhead)" style="fill: none;"></line></g><g><text x="975" y="198" class="messageText" style="text-anchor: middle;">Bob's app uses &lt;BA public key hash&gt; to identify Alice</text><text x="975" y="215" class="messageText" style="text-anchor: middle;">and decrypts the messages with Bob's &lt;BA private key&gt;</text><line x1="875" y1="205" x2="1075" y2="205" class="messageLine1" stroke-width="2" stroke="black" marker-end="url(#arrowhead)" style="stroke-dasharray: 3, 3; fill: none;"></line></g><g><rect x="800" y="215" fill="#EDF2AE" stroke="#666" width="150" height="100" rx="0" ry="0" class="note"></rect><text x="796" y="239" class="noteText"><tspan x="816">App creates</tspan></text><text x="796" y="255" class="noteText"><tspan x="816">"message received"</tspan></text><text x="796" y="271" class="noteText"><tspan x="816">including:</tspan></text><text x="796" y="287" class="noteText"><tspan x="816">- msg correlation ID</tspan></text><text x="796" y="303" class="noteText"><tspan x="816">- timestamp</tspan></text></g><g><text x="675" y="343" class="messageText" style="text-anchor: middle;">"message received" signed with &lt;BA private key&gt;, encrypted with Alice's &lt;AB public key&gt;</text><text x="675" y="360" class="messageText" style="text-anchor: middle;">{to: &lt;AB public key hash&gt;, message: &lt;encrypted with AB public key&gt;} (also signed/encrypted with &lt;B_AB server private/public keys&gt;)</text><line x1="875" y1="350" x2="475" y2="350" class="messageLine0" stroke-width="2" stroke="black" marker-end="url(#arrowhead)" style="fill: none;"></line></g><g><text x="375" y="378" class="messageText" style="text-anchor: middle;">"message received": Alice's app uses &lt;AB public key hash&gt; to identify Bob</text><text x="375" y="395" class="messageText" style="text-anchor: middle;">and decrypts "message received" with Alice's &lt;AB private key&gt;</text><line x1="475" y1="385" x2="275" y2="385" class="messageLine0" stroke-width="2" stroke="black" marker-end="url(#arrowhead)" style="fill: none;"></line></g><g><text x="175" y="413" class="messageText" style="text-anchor: middle;">"message received" shown to Alice</text><line x1="275" y1="420" x2="75" y2="420" class="messageLine1" stroke-width="2" stroke="black" marker-end="url(#arrowhead)" style="stroke-dasharray: 3, 3; fill: none;"></line></g><g><rect x="0" y="440" fill="#eaeaea" stroke="#666" width="150" height="65" rx="3" ry="3" class="actor"></rect><text x="75" y="472.5" dominant-baseline="central" alignment-baseline="central" class="actor" style="text-anchor: middle; font-size: 14px;"><tspan x="75" dy="0">Alice</tspan></text></g><g><rect x="200" y="440" fill="#eaeaea" stroke="#666" width="150" height="65" rx="3" ry="3" class="actor"></rect><text x="275" y="472.5" dominant-baseline="central" alignment-baseline="central" class="actor" style="text-anchor: middle; font-size: 14px;"><tspan x="275" dy="0">Alice's app</tspan></text></g><g><rect x="400" y="440" fill="#eaeaea" stroke="#666" width="150" height="65" rx="3" ry="3" class="actor"></rect><text x="475" y="472.5" dominant-baseline="central" alignment-baseline="central" class="actor" style="text-anchor: middle; font-size: 14px;"><tspan x="475" dy="0">Alice's server</tspan></text></g><g><rect x="600" y="440" fill="#eaeaea" stroke="#666" width="150" height="65" rx="3" ry="3" class="actor"></rect><text x="675" y="472.5" dominant-baseline="central" alignment-baseline="central" class="actor" style="text-anchor: middle; font-size: 14px;"><tspan x="675" dy="0">Bob's server</tspan></text></g><g><rect x="800" y="440" fill="#eaeaea" stroke="#666" width="150" height="65" rx="3" ry="3" class="actor"></rect><text x="875" y="472.5" dominant-baseline="central" alignment-baseline="central" class="actor" style="text-anchor: middle; font-size: 14px;"><tspan x="875" dy="0">Bob's app</tspan></text></g><g><rect x="1000" y="440" fill="#eaeaea" stroke="#666" width="150" height="65" rx="3" ry="3" class="actor"></rect><text x="1075" y="472.5" dominant-baseline="central" alignment-baseline="central" class="actor" style="text-anchor: middle; font-size: 14px;"><tspan x="1075" dy="0">Bob</tspan></text></g></svg>
\ No newline at end of file