3 files changed, 11 insertions, 4 deletions
diff --git a/include/olm/error.h b/include/olm/error.h
index 1c44de8..9d44a94 100644
--- a/include/olm/error.h
+++ b/include/olm/error.h
@@ -46,6 +46,11 @@ enum OlmErrorCode {
      */
     OLM_BAD_LEGACY_ACCOUNT_PICKLE = 13,
 
+    /**
+     * Received message had a bad signature
+     */
+    OLM_BAD_SIGNATURE = 14,
+
     /* remember to update the list of string constants in error.c when updating
      * this list. */
 };
diff --git a/include/olm/inbound_group_session.h b/include/olm/inbound_group_session.h
index e24f377..49992b2 100644
--- a/include/olm/inbound_group_session.h
+++ b/include/olm/inbound_group_session.h
@@ -97,7 +97,7 @@ size_t olm_init_inbound_group_session(
     OlmInboundGroupSession *session,
     uint32_t message_index,
 
-    /* base64-encoded key */
+    /* base64-encoded keys */
     uint8_t const * session_key, size_t session_key_length
 );
 
diff --git a/include/olm/message.h b/include/olm/message.h
index 5eb504d..61012c9 100644
--- a/include/olm/message.h
+++ b/include/olm/message.h
@@ -37,7 +37,8 @@ extern "C" {
 size_t _olm_encode_group_message_length(
     uint32_t chain_index,
     size_t ciphertext_length,
-    size_t mac_length
+    size_t mac_length,
+    size_t signature_length
 );
 
 /**
@@ -49,7 +50,8 @@ size_t _olm_encode_group_message_length(
  * output:             where to write the output. Should be at least
  *                     olm_encode_group_message_length() bytes long.
  * ciphertext_ptr:     returns the address that the ciphertext
- *                     should be written to, followed by the MAC.
+ *                     should be written to, followed by the MAC and the
+ *                     signature.
  *
  * Returns the size of the message, up to the MAC.
  */
@@ -76,7 +78,7 @@ struct _OlmDecodeGroupMessageResults {
  */
 void _olm_decode_group_message(
     const uint8_t *input, size_t input_length,
-    size_t mac_length,
+    size_t mac_length, size_t signature_length,
 
     /* output structure: updated with results */
     struct _OlmDecodeGroupMessageResults *results