Draft: draft-ietf-mls-protocol

Commentary: This PR addresses two issues that were noted in draft-05 , one that is definitely a bug , and one that should improve security analysis . In draft-05 , a circular dependency was introduced , wherein the confirmation MAC was calculated from the transcript , which includes the GroupOperation , which includes the confirmation MAC . Here we move the confirmation MAC up to the MLSPlaintext object to avoid this circularity . In all prior versions , the transcript covered only the GroupOperation objects , not the sender metadata or signatures . Here we cover the whole MLSPlaintext object , but in " staggered " form -- the confirmation MAC and signature are n't entered into the transcript until the next epoch . 
 Here 's the Weekly Digest for : - - Last week 2 issues were created . Of these , 2 issues have been closed and 0 issues are still open . : heart : , by : heart : , by - - Last week , 4 pull requests were created , updated or merged . Last week , 4 pull requests were merged . : purpleheart : , by : purpleheart : , by : purpleheart : , by : purpleheart : , by - - Last week there were 9 commits . : hammerandwrench : by : hammerandwrench : by : hammerandwrench : by : hammerandwrench : by : hammerandwrench : by : hammerandwrench : by : hammerandwrench : by : hammerandwrench : by : hammerandwrench : by - - Last week there was 1 contributor . : bustinsilhouette : - - Last week there were no stargazers . - - Last week there were no releases . - - That 's all for last week , please < kbd : eyes : Watch</kbdand < kbd : star : Star</kbdthe repository to receive next weekly updates . : smiley : You can also . 
 Here 's the Weekly Digest for : - - Last week 5 issues were created . Of these , 1 issues have been closed and 4 issues are still open . : greenheart : , by : greenheart : , by : greenheart : , by : greenheart : , by : heart : , by - - Last week , 9 pull requests were created , updated or merged . Last week , 3 pull requests were opened . : greenheart : , by : greenheart : , by : greenheart : , by Last week , 1 pull request was updated . : yellowheart : , by Last week , 5 pull requests were merged . : purpleheart : , by : purpleheart : , by : purpleheart : , by : purpleheart : , by : purpleheart : , by - - Last week there were 8 commits . : hammerandwrench : by : hammerandwrench : by : hammerandwrench : by : hammerandwrench : by : hammerandwrench : by : hammerandwrench : by : hammerandwrench : by : hammerandwrench : by - - Last week there were 2 contributors . : bustinsilhouette : : bustinsilhouette : - - Last week there was 1 stargazer . : star : You are the star ! : star2 : - - Last week there were no releases . - - That 's all for last week , please < kbd : eyes : Watch</kbdand < kbd : star : Star</kbdthe repository to receive next weekly updates . : smiley : You can also .
Paragraph (version B):
This structure incorporates everything in an MLSPlaintext up to the
confirmation field in the transcript that is included in that
confirmation field (via the GroupState).  The confirmation and
signature fields are then included in the transcript for the next
operation.  The intermediate hash enables implementations to in
corporate a plaintext into the transcript without having to store the
whole MLSPlaintextOpAuthData structure.