Dan,

This is the general idea. The major reason is that there = are various ways to protect the data and if you are not mandating one for interoperability then it can be more general

For example we have the following text when discussing = security in the RTP payloads specifications.

RTP packets using the payload format defined in this specification

are subject to the security considerations = discussed in the RTP

specification [RFC3550] and any appropriate = RTP profile. The main

security considerations for the RTP packet = carrying the RTP payload

format defined within this memo are = confidentiality, integrity, and

source authenticity. Confidentiality = is achieved by encryption of

the RTP payload. Integrity of the RTP = packets is achieved through a

suitable cryptographic integrity protection = mechanism. Such a

cryptographic system may also allow the = authentication of the source

of the payload. A suitable security = mechanism for this RTP payload

format should provide confidentiality, = integrity protection, and at

least source authentication capable of = determining if an RTP packet

is from a member of the RTP = session.

Note that the appropriate mechanism to = provide security to RTP and

payloads following this memo may vary. = It is dependent on the

application, the transport, and the = signaling protocol employed.

Therefore, a single mechanism is not = sufficient, although if

suitable, usage of the Secure Real-time = Transport Protocol (SRTP)

[RFC3711] recommended. Other = mechanisms that may be used are IPsec

[RFC4301] Transport Layer Security (TLS) = [RFC5246] (RTP over TCP);

other alternatives may = exist.

Roni Even

From:= rai-bounces@ietf.org [mailto:rai-bounces@ietf.org] On Behalf Of = Dan York
Sent: Tuesday, July 14, 2009 11:16 PM
To: Roni Even
Cc: 'Daniel Burnett'; speechsc@ietf.org; 'Saravanan Shanmugham'; rai@ietf.org
Subject: Re: [RAI] RAI review of = draft-ietf-speechsc-mrcpv2-19

Roni,

The current text at http://tools.ietf.org/html/draft-ietf-speechsc-mrcpv2-19#section-12= .3 is:

------

12.3. =
Media session protection

Sensitive =
data is also carried on media sessions terminating on MRCPv2 servers =
(the other end of a media channel may or may not be on the MRCPv2 =
client). This data includes the user's spoken utterances and the output =
of text-to-speech operations. MRCPv2 servers MUST support SRTP for =
protection of audio media sessions. MRCPv2 clients that originate or =
consume audio similarly MUST support SRTP. Alternative media channel =
protection MAY be used if desired (e.g. =
IPSEC).

------

Based on your comments and the srtp-not-mandatory = draft (which was just revised to = http://tools.ietf.org/html/draft-ietf-avt-srtp-not-mandatory-03 ), my understanding would be that you are advocating something more like = this:

------

12.3. Media session =
protection

Sensitive=
 data is also carried on media sessions terminating on MRCPv2 servers =
(the other end of a media channel may or may not be on the MRCPv2 =
client). This data includes the user's spoken utterances   =
 and the output of text-to-speech operations. MRCPv2 servers MUST =
support a security mechanism for protection of audio media sessions. =
MRCPv2 clients that originate or consume audio similarly MUST support a =
security mechanism for protection of the =
audio.

------

Is that an accurate summary of your feedback? = Would that text be acceptable?

Regards,

Dan

On Jul 9, 2009, at 4:56 PM, Roni Even = wrote:

Eric,
My comment is that in this case in AVT we say that you do not need = to
mandate SRTP but mandate a security mechanism that can be not only = SRTP but
in a different layer like ipsec. This is why I gave a reference to = the
srtp-not-mandatory draft

Roni

-----Original Message-----

From: Eric Burger [mailto:eburger@standardstrack.= com]

Sent: Thursday, July 09, 2009 11:28 = PM

To: Roni Even

Cc: Saravanan Shanmugham; Daniel Burnett; speechsc@ietf.org;

rai@ietf.org

Subject: Re: RAI review of = draft-ietf-speechsc-mrcpv2-19

The reality is that NO ONE has implemented any = security to date. The

GENART reviewer raised the same issue, and so far = the work group has

the same response: MRCPv2 (the speechsc work group) = is not planning on

figuring out which of the seven key exchange = mechanisms to use in

SIP. We are counting on the community = publishing something, and

people using it. After all, we are the = "using SIP for media resource

control" work group, not the "media = resource control work group using

something like SIP for = control."

Does this work for you?

On Jul 7, 2009, at 3:40 PM, Roni Even = wrote:

[snip]

18. In section 12.3 the suggestion is = to use SRTP as the mandatory

interoperability mode. If the reason for mandating = SRTP is for a

common mode you should also decide on a key = exchange mechanism. I

suggest you look athttp://tools.iet= f.org/html/draft-ietf-avt-srtp-

not-mandatory-02

for discussion on media security.

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