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Re: [Sip] R-CERTS in draft-ietf-sip-media-security-requirements



Dan,

On Apr 21, 2008, at 2:22 PM, Dan Wing wrote:

> During WGLC an objection was raised about R-CERTS in
> draft-ietf-sip-media-security-requirements.  I currently have  
> proposals for:
>
>  * reverting to the R12 text
>  * sticking with R-CERTS text
>  * removing the text completely
>
> I would like to understand what people want this requirement to  
> *mean* -- does
> it say what you think it should say?  Does it miss some aspect of
> signing/certificates that is important?

DY> I think this is an important requirement in that it allows the use  
of self-signed certificates.  If I recall previous discussions  
correctly, the major concern was that we didn't want to get in a  
situation where in order to use a key management protocol all parties  
were *required* to obtain certificates signed by a formal Certificate  
Authority.   We wanted any solution to allow the optional use of self- 
signed certs for various instances where CA-signed certs might not be  
appropriate or necessary.

DY> So I think the *intent* of the requirement - as I understand it -  
is still important to capture.  What about merging R12 and R-CERTS by  
simply replacing the "CA-issued" with "3rd-party-signed", as in:

   R-CERTS:  If the media security key management protocol
         employs certificates, it MUST be able to make use of both
         self-signed and 3rd-party-signed certificates.

DY> Or is that muddying things up even more?

My 2 cents,
Dan

>
>
> -----
>
> Details:
>
> In draft-ietf-sip-media-security-requirements-00 and -01, we had:
>
>   R12:  The media security key management protocol MUST NOT
>         require 3rd parties to sign certificates.
>
> in draft-ietf-sip-media-security-requirements-02, this From sip-bounces at ietf.org  Fri May  2 02:46:03 2008
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From: Dan York <dyork at voxeo.com>
To: Dan Wing <dwing at cisco.com>
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Subject: Re: [Sip] R-CERTS in draft-ietf-sip-media-security-requirements
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Dan,

On Apr 21, 2008, at 2:22 PM, Dan Wing wrote:

> During WGLC an objection was raised about R-CERTS in
> draft-ietf-sip-media-security-requirements.  I currently have  
> proposals for:
>
>  * reverting to the R12 text
>  * sticking with R-CERTS text
>  * removing the text completely
>
> I would like to understand what people want this requirement to  
> *mean* -- does
> it say what you think it should say?  Does it miss some aspect of
> signing/certificates that is important?

DY> I think this is an important requirement in that it allows the use  
of self-signed certificates.  If I recall previous discussions  
correctly, the major concern was that we didn't want to get in a  
situation where in order to use a key management protocol all parties  
were *required* to obtain certificates signed by a formal Certificate  
Authority.   We wanted any solution to allow the optional use of self- 
signed certs for various instances where CA-signed certs might not be  
appropriate or necessary.

DY> So I think the *intent* of the requirement - as I understand it -  
is still important to capture.  What about merging R12 and R-CERTS by  
simply replacing the "CA-issued" with "3rd-party-signed", as in:

   R-CERTS:  If the media security key management protocol
         employs certificates, it MUST be able to make use of both
         self-signed and 3rd-party-signed certificates.

DY> Or is that muddying things up even more?

My 2 cents,
Dan

>
>
> -----
>
> Details:
>
> In draft-ietf-sip-media-security-requirements-00 and -01, we had:
>
>   R12:  The media security key management protocol MUST NOT
>         require 3rd parties to sign certificates.
>
> in draft-ietf-sip-media-security-requirements-02, this was renawas renamed  
> to R-CERTS
> and also had its text change to:
>
>   R-CERTS:  If the media security key management protocol
>         employs certificates, it MUST be able to make use of both
>         self-signed and CA-issued certificates.  As an alternative,
>         the media security key management protocol MAY make use of
>         "bare" public keys.
>
>
> Here is how some key management systems would fare with the original  
> R12 text:
>
>  * RFC4474 would comply -- because RFC4474 allows both self-signed
>    certificates and allows CA-signed certificates (reference end of
>    Step 1 of Section 6 of RFC4474).  One might reasonably expect most
>    deployments will use CA-signed certificates.
>
>  * OpenPGP certificates (if someone were to use it for SRTP
>    keying) would comply -- because R12 allows you to sign your own
>    key and does not require someone else sign your key.  One might
>    expect most deployments would include signatures by other
>    people (3rd parties).
>
>  * ZRTP would comply -- because there are no 3rd party signatures
>    whatsoever.
>
>  * MIKEY-RSA complies -- because it allows self-signed certificates
>    (reference the first bullet of Section 4.3.2 of RFC3830).
>
>  * Identity-Based Encryption (if someone were to use it for SRTP
>    keying) would comply -- because IBE uses 'bare' public keys.
>
>
> and with the R-CERTS text:
>
>  * RFC4474 would comply (same reason as R12).
>
>  * OpenPGP certificates (if someone were to use it for SRTP keying)
>    would not comply -- because R-CERTS allows you to sign your own
>    key, but only mentions Certificate Authorities as 3rd party
>    signers; OpenPGP does not have 'certificate authorities'.
>
>  * ZRTP would comply (same reason as R12).
>
>  * MIKEY-RSA complies (same reason as R12).
>
>  * Identity-Based Encryption (if someone were to use it for SRTP
>    keying) would comply (same reason as R12).
>
> -d
>
> _______________________________________________
> Sip mailing list  https://www.ietf.org/mailman/listinfo/sip
> This list is for NEW development of the core SIP Protocol
> Use sip-implementors at cs.columbia.edu for questions on current sip
> Use sipping at ietf.org for new developments on the application of sip

-- 
Dan York, CISSP, Director of Emerging Communication Technology
Office of the CTO    Voxeo Corporation     dyork at voxeo.com
Phone: +1-407-455-5859  Skype: danyork  http://www.voxeo.com
Blogs: http://blogs.voxeo.com  http://www.disruptivetelephony.com

Build voice applications based on open standards.
Find out how at http://www.voxeo.com/free





_______________________________________________
Sip mailing list  https://www.ietf.org/mailman/listinfo/sip
This list is for NEW development of the core SIP Protocol
Use sip-implementors at cs.columbia.edu for questions on current sip
Use sipping at ietf.org for new developments on the application of sip


med  
> to R-CERTS
> and also had its text change to:
>
>   R-CERTS:  If the media security key management protocol
>         employs certificates, it MUST be able to make use of both
>         self-signed and CA-issued certificates.  As an alternative,
>         the media security key management protocol MAY make use of
>         "bare" public keys.
>
>
> Here is how some key management systems would fare with the original  
> R12 text:
>
>  * RFC4474 would comply -- because RFC4474 allows both self-signed
>    certificates and allows CA-signed certificates (reference end of
>    Step 1 of Section 6 of RFC4474).  One might reasonably expect most
>    deployments will use CA-signed certificates.
>
>  * OpenPGP certificates (if someone were to use it for SRTP
>    keying) would comply -- because R12 allows you to sign your own
>    key and does not require someone else sign your key.  One might
>    expect most deployments would include signatures by other
>    people (3rd parties).
>
>  * ZRTP would comply -- because there are no 3rd party signatures
>    whatsoever.
>
>  * MIKEY-RSA complies -- because it allows self-signed certificates
>    (reference the first bullet of Section 4.3.2 of RFC3830).
>
>  * Identity-Based Encryption (if someone were to use it for SRTP
>    keying) would comply -- because IBE uses 'bare' public keys.
>
>
> and with the R-CERTS text:
>
>  * RFC4474 would comply (same reason as R12).
>
>  * OpenPGP certificates (if someone were to use it for SRTP keying)
>    would not comply -- because R-CERTS allows you to sign your own
>    key, but only mentions Certificate Authorities as 3rd party
>    signers; OpenPGP does not have 'certificate authorities'.
>
>  * ZRTP would comply (same reason as R12).
>
>  * MIKEY-RSA complies (same reason as R12).
>
>  * Identity-Based Encryption (if someone were to use it for SRTP
>    keying) would comply (same reason as R12).
>
> -d
>
> _______________________________________________
> Sip mailing list  https://www.ietf.org/mailman/listinfo/sip
> This list is for NEW development of the core SIP Protocol
> Use sip-implementors at cs.columbia.edu for questions on current sip
> Use sipping at ietf.org for new developments on the application of sip

-- 
Dan York, CISSP, Director of Emerging Communication Technology
Office of the CTO    Voxeo Corporation     dyork at voxeo.com
Phone: +1-407-455-5859  Skype: danyork  http://www.voxeo.com
Blogs: http://blogs.voxeo.com  http://www.disruptivetelephony.com

Build voice applications based on open standards.
Find out how at http://www.voxeo.com/free





_______________________________________________
Sip mailing list  https://www.ietf.org/mailman/listinfo/sip
This list is for NEW development of the core SIP Protocol
Use sip-implementors at cs.columbia.edu for questions on current sip
Use sipping at ietf.org for new developments on the application of sip