Request to review Media Type */rtp-enc-aescm128 for 3GPP
Magnus Westerlund
magnus.westerlund at ericsson.com
Fri Sep 22 09:55:57 CEST 2006
Hi,
Thanks for the quick feedback. Please review the below updated text. I
would appreciate if all comments are received within two weeks. After
that I will need to prepare an official contribution to the next 3GPP
SA4 meeting to do these changes in the specification.
Cheers
Magnus
[60] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform Resource
Identifier (URI): Generic Syntax", STD 66, RFC 3986, January 2005.
[96] Freed, N. and J. Klensin, "Media Type Specifications and
Registration Procedures", BCP 13, RFC 4288, December 2005.
K.1.4.1 MIME type definition
K.1.4.1.1 audio/rtp-enc-aescm128
Type name: audio
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 3986 [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 3986 [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 fulfills no purpose.
Encoding considerations:
This type is framed as defined in [96].
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
magnus.westerlund at ericsson.com
Intended usage:
Common
Restrictions on usage:
This type is only defined for transfer via RTP (RFC 3550).
Author
3GPP SA4 WG
Change controller:
3GPP TSG SA
K.1.4.1.2 video/rtp-enc-aescm128
Type name: video
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 3986 [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 3986 [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 fulfills no purpose.
Encoding considerations:
This type is framed as defined in [96].
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
magnus.westerlund at ericsson.com
Intended usage:
Common
Restrictions on usage:
This type is only defined for transfer via RTP (RFC 3550).
Author
3GPP SA4 WG
Change controller:
3GPP TSG SA
K.1.4.1.3 text/rtp-enc-aescm128
Type name: text
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 3986 [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 3986 [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 fulfills no purpose.
Encoding considerations:
This type is framed as defined in [96].
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
magnus.westerlund at ericsson.com
Intended usage:
Common
Restrictions on usage:
This type is only defined for transfer via RTP (RFC 3550).
Author
3GPP SA4 WG
Change controller:
3GPP TSG SA
--
Magnus Westerlund
Multimedia Technologies, Ericsson Research EAB/TVA/A
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