more comments

openmls/src/group/mls_group/processing.rs

@@ -270,6 +270,7 @@ impl MlsGroup {
         // Checks the following semantic validation:
         //  - ValSem010
         //  - ValSem246 (as part of ValSem010)
+        //  - https://validation.openmls.tech/#valn1203
         let (content, credential) =
             unverified_message.verify(self.ciphersuite(), provider.crypto(), self.version())?;
 
@@ -361,6 +362,7 @@ impl MlsGroup {
     ///  - ValSem003
     ///  - ValSem006
     ///  - ValSem007 MembershipTag presence
+    ///  - https://validation.openmls.tech/#valn1202
     pub(crate) fn decrypt_message(
         &mut self,
         crypto: &impl OpenMlsCrypto,

openmls/src/group/public_group/process.rs

@@ -200,6 +200,7 @@ impl PublicGroup {
         // Checks the following semantic validation:
         //  - ValSem010
         //  - ValSem246 (as part of ValSem010)
+        //  - https://validation.openmls.tech/#valn1203
         let (content, credential) =
             unverified_message.verify(self.ciphersuite(), crypto, self.version())?;
 

openmls/src/group/public_group/staged_commit.rs

@@ -47,6 +47,7 @@ impl PublicGroup {
         let ciphersuite = self.ciphersuite();
 
         // Verify epoch
+        // https://validation.openmls.tech/#valn1201
         if mls_content.epoch() != self.group_context().epoch() {
             log::error!(
                 "Epoch mismatch. Got {:?}, expected {:?}",
@@ -99,7 +100,8 @@ impl PublicGroup {
             self.validate_leaf_node(update_path.leaf_node())?;
         }
 
-        // Validate the staged proposals by doing the following checks:
+        // Validate the staged proposals. This implements https://validation.openmls.tech/#valn1204.
+        // This is done by doing the following checks:
 
         // ValSem101
         // ValSem102
@@ -247,6 +249,7 @@ impl PublicGroup {
             diff.apply_received_update_path(crypto, ciphersuite, sender_index, update_path)?;
         } else if apply_proposals_values.path_required {
             // ValSem201
+            // https://validation.openmls.tech/#valn1206
             return Err(StageCommitError::RequiredPathNotFound);
         };
 

openmls/src/treesync/treekem.rs

@@ -408,6 +408,7 @@ impl UpdatePathIn {
         let leaf_node_in = self.leaf_node().clone();
         let verifiable_leaf_node = leaf_node_in.into_verifiable_leaf_node();
         match verifiable_leaf_node {
+            // https://validation.openmls.tech/#valn1208
             VerifiableLeafNode::Commit(mut commit_leaf_node) => {
                 let pk = &commit_leaf_node
                     .signature_key()