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ui/sendviewcontroller.md

@@ -23,4 +23,19 @@ the state after composing is one of the following:
    - sent as letter
    - sent as postcard
 
-## internal states
+## internal states
\ No newline at end of file
+
+### security
+
+*  Letter
+   -  we have a key for every recipient and no downgrade is enforced
+*  Postcard
+   -  to everyone 
+      -  we have no key for every recipient
+      -  downgraded letter (could be the letter, but the user wants to send a letter)
+   -  some recipients will get a "secure" mail, because we have a key of them
+   -  partial encrypted mail (parts of the message are encrypted)
+   -  censored mail (not invertible destruction of text parts)
+
+### other
+