Currently, there are several valid ratchet_tree for one tree: the sender can choose ("SHOULD") to omit some (but not all) blank nodes at the right of the tree.
This PR changes this: the sender MUST omit all the blank nodes at the right of the tree, and the receiver MUST check that it was done correctly (i.e., the last node of ratchet_tree is non-blank).
As discussed in mlswg/mls-implementations#102 .
Currently, there are several valid
ratchet_treefor one tree: the sender can choose ("SHOULD") to omit some (but not all) blank nodes at the right of the tree. This PR changes this: the sender MUST omit all the blank nodes at the right of the tree, and the receiver MUST check that it was done correctly (i.e., the last node ofratchet_treeis non-blank).