I am the assigned Gen-ART reviewer for this draft. The General Area Review Team (Gen-ART) reviews all IETF documents being processed by the IESG for the IETF Chair. Please wait for direction from your document shepherd or AD before posting a new version of the draft. For more information, please see the FAQ at < http://wiki.tools.ietf.org/area/gen/trac/wiki/GenArtfaq>. Document: draft-ietf-rtcweb-alpn-03 Reviewer: Russ Housley Review Date: 2016-04-18 IETF LC End Date: 2016-04-21 IESG Telechat date: unknown Summary: Almost Ready Major Concerns: None Minor Concerns: In several places, the document says: "These confidentiality protections do not apply to data that is sent using data channels." It took me a moment to figure out what was being said. I think it would really help the reader to say at the beginning something like: "The confidentiality protections ensure that media is protected from other applications, but the confidentiality protections do not extend to traffic on the data channels." Section 3 includes this paragraph: Generally speaking, ensuring confidentiality depends on authenticating the communications peer. This mechanism explicitly does not define a specific authentication method; a WebRTC endpoint that accepts a session with this ALPN identifier MUST respect confidentiality no matter what identity is attributed to a peer. I understand why authentication and confidentiality are often used together. However, it is very unclear to me why there ought to be a linkage between c-webrtc and authentication since this service really is only a promise to not share media with other applications. A similar discussion in the security considerations talks about assurance that the "media was delivered to the user that was authenticated." Again, if there is no authentication, I do not see how the assurance associated with this mechanism changes. Nits: After reading the whole document, I went back and read the Abstract again. I do not think it captures the real intent of the document. I have tried to provide an alternative, but it probably needs further work: This document specifies two Application Layer Protocol Negotiation (ALPN) labels for use with Datagram Transport Layer Security (DTLS) and Web Real-Time Communications (WebRTC). With the first label, a DTLS session is used to establish keys for Secure Real-time Transport Protocol (SRTP), known as DTLS-SRTP. The second label also uses DTLS-SRTP, but the peers also agree to maintain the confidentiality of the media by not sharing it with other applications.