Merge 37f1536532 into bf5fbc9945

Signed-off-by: tusooa <tusooa@kazv.moe>

Co-authored-by: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>

changelogs/client_server/newsfragments/2394.clarification

@@ -0,0 +1 @@
+Correct some errors in the description of the validation process for incoming Olm-encrypted messages.

content/client-server-api/modules/end_to_end_encryption.md

@@ -1781,6 +1781,7 @@ of olm sessions maintained per device should be at least 4.
 ###### Validation of incoming decrypted events
 
 {{% changed-in v="1.15" %}} Existing checks made more explicit, and checks for `sender_device_keys` added.
+{{% changed-in v="1.19" %}} Corrections to some errors in the description of the verification checks.
 
 After decrypting an incoming encrypted event, clients MUST apply the
 following checks:
@@ -1788,8 +1789,9 @@ following checks:
 1.  The `sender` property in the decrypted content must match the
     `sender` of the event.
 2.  The `keys.ed25519` property in the decrypted content must match
-    the `sender_key` property in the cleartext `m.room.encrypted`
-    event body.
+    the Ed25519 identity key of the sending device. This key can be
+    obtained from either [`/keys/query`](#post_matrixclientv3keysquery)
+    or the `sender_device_keys` object (see below).
 3.  The `recipient` property in the decrypted content must match
     the user ID of the local user.
 4.  The `recipient_keys.ed25519` property in the decrypted content
@@ -1797,11 +1799,11 @@ following checks:
 5.  Where `sender_device_keys` is present in the decrypted content:
     1.  `sender_device_keys.user_id` must also match the `sender`
         of the event.
-    2.  `sender_device_keys.keys.ed25519:<device_id>` must also match
+    2.  `sender_device_keys.keys.curve25519:<device_id>` must match
         the `sender_key` property in the cleartext `m.room.encrypted`
         event body.
-    3.  `sender_device_keys.keys.curve25519:<device_id>` must match
-        the Curve25519 key used to establish the Olm session.
+    3.  `sender_device_keys.keys.ed25519:<device_id>` must be the same
+        as the `keys.ed25519` property in the decrypted content.
     4.  The `sender_device_keys` structure must have a valid signature
         from the key with ID `ed25519:<device_id>` (i.e., the sending
         device's Ed25519 key).