Pre review of 3GPP MIME type for RTP payload format

[Magnus Westerlund]

Hi,

We have detected a copy and paste error of the complete Appendix K in 
the first of the below references, and it has been replaced with the 
following version.

http://www.3gpp.org/ftp/tsg_sa/WG4_CODEC/TSGS4_32/Docs/S4-040481.zip

Cheers

Magnus

Magnus Westerlund wrote:

> Hi,
> 
> I would like to have a pre registration request review of the below 
> propsed MIME type for a RTP payload format. This registration request is 
> intended to use the updated registration procedure based on 
> specification available from other standards body.
> 
> The specification that the registration belongs to can be found in the 
> following 3GPP contribution:
> 
> http://www.3gpp.org/ftp/tsg_sa/WG4_CODEC/TSGS4_32/Docs/S4-040460.zip
> Which is the specification delta that included the RTP payload format 
> defined within to the following specification:
> 
> http://www.3gpp.org/ftp/Specs/latest/Rel-6/26_series/26234-600.zip
> 
> The registration template for this looks like the following:
> ------------------------------------------------------------
> 
> MIME media type name: audio, video, text, application, image
> 
> MIME subtype name: rtp.enc.aescm128
> 
> Required parameters:
> 
> opt:     The payload type number of the payload type contained in the
>         encrypted payload. An integer value between 0-127.
> 
> rate:     The timestamp rate of this payload type, which shall be the same
>         as that of the original payload type. This is an integer value
>         between 1 and 2^32.
> 
> ContentID: The OMA DRM content ID [75] used to identify the content when
>         establishing a crypto context. The value is an RFC 2396 [60]
>         URI, which shall be quoted using <">.
> 
> RightsIssuerURL: The right issuer URL as defined by OMA DRM [75]. The
>         value is an URI in accordance with RFC 2396 [60], which shall be
>         quoted using <">.
> 
> IVnonce: The value of this parameter is the nonce that forms the IV as
>         specified by the crypto transform, encoded using Base 64 [69].
> 
> Optional parameters:
> 
> SelectiveEncryption:     Indicates if this stream is selectively
>         encrypted. Allowed values are 0 (false) and 1 (true). If not
>         present, selective encryption shall not be used. Please note
>         that unless this indicator is integrity protected, it fulfils no
>         purpose.
> 
> Encoding considerations:
>         This type is only defined for transfer via RTP (RFC 3550).
> 
> Security considerations:
> 
> See considerations raised in RTP RFC 3550 [9] and any applicable
> profile like RFC 3551 [10] or RFC 3711 [72]. Further see 3GPP TS
> 26.234, Release 6, Annex K for comments on security issues. The main
> issues that exists are:
> 
> - This RTP payload format only confidentiality protects the RTP payload, 
> thus header information is leaked, similarly to SRTP.
> 
> - The use of stream ciphers as AES CM and no integrity protection allows 
> an attacker to purposefully attack the content of the encrypted RTP 
> payload by switching individual bits.
> 
> - The usage of selective encryption without integrity protection allows 
> for an attacker to perform any replacements of complete RTP payloads and 
> packets it desires.
> 
> - The payload format makes the receiver vulnerable to denial of service 
> attacks that inserts RTP packets into the stream, that the receiver then 
> interprets as being encrypted thus wasting computational resources. To 
> prevent this attack, authentication needs to be used.
> Interoperability considerations:
> 
> Published specification:
> 3GPP TS 26.234, Release 6.
> Open Mobile Alliance DRM Content Format V2.0
> 
> Applications which use this media type:
>     Third Generation Partnership Project (3GPP) Packet-switched
>         Streaming Service (PSS) clients and servers, which supports the
>         Open Mobile Alliance's specification of Digital Rights
>         Management version 2.0.
> 
> Additional information:
> 
> Magic number(s): N/A
> File extension(s): N/A
> Macintosh File Type Code(s): N/A
> 
> Person & email address to contact for further information:
>     magnus.westerlund at ericsson.com
> 
> Intended usage:
> Common
> 
> Author/Change controller:
> 
> 3GPP TSG SA
> 
> ---- End of template ---
> 
> Hope for comments within a week. Otherwise any changes within 3GPP will 
> be more difficult.
> 
> Thanks
> 
> Magnus Westerlund
> 
> Multimedia Technologies, Ericsson Research EAB/TVA/A
> ----------------------------------------------------------------------
> Ericsson AB                | Phone +46 8 4048287
> Torshamsgatan 23           | Fax   +46 8 7575550
> S-164 80 Stockholm, Sweden | mailto: magnus.westerlund at ericsson.com
> 


-- 

Magnus Westerlund

Multimedia Technologies, Ericsson Research EAB/TVA/A
----------------------------------------------------------------------
Ericsson AB                | Phone +46 8 4048287
Torshamsgatan 23           | Fax   +46 8 7575550
S-164 80 Stockholm, Sweden | mailto: magnus.westerlund at ericsson.com