diff --git a/draft-ietf-mls-architecture.md b/draft-ietf-mls-architecture.md index 597c0f0..13e222e 100644 --- a/draft-ietf-mls-architecture.md +++ b/draft-ietf-mls-architecture.md @@ -643,7 +643,7 @@ must agree on a single MLS Commit message that ends each epoch and begins the next one. In practice, there's a realistic risk of two members generating Commit messages -at the same time, based on the same counter, and both attempting to send them to +at the same time, based on the same epoch, and both attempting to send them to the group at the same time. The extent to which this is a problem, and the appropriate solution, depends on the design of the Delivery Service. Per the CAP theorem {{CAPBR}}, there are two general classes of distributed system that the @@ -662,11 +662,12 @@ are described in the next two subsections. However, note that a malicious Delivery Service could also reorder messages or provide an inconsistent view to different users. The "generation" counter in MLS messages provides per-sender loss detection and ordering that cannot be -manipulated by the DS. A mechanism for more robust protections is discussed in -{{?I-D.ietf-mls-extensions}}. A DS can cause a partition in the group by +manipulated by the DS, but this does not provide complete protection against +partitioning. A DS can cause a partition in the group by partitioning key exchange messages; this can be detected only by out-of-band comparison (e.g., confirming that all clients have the same -`epoch_authenticator` value`). +`epoch_authenticator` value`). A mechanism for more robust protections is discussed in +{{?I-D.ietf-mls-extensions}}. Other forms of Delivery Service misbehavior are still possible that are not easy to detect. For instance, a Delivery Service can simply refuse to relay messages