[Css-csts] RE: [Smwg] Issues regarding level of authentication and credentialsalogorithms for transfer services

[Martin Götzelmann]

Dear John,
 
Just a few thoughts on the subject ...
 
While the Framework Specification indeed does not "not address the mechanism for exchanging authentication and access control information associated with the creation of transfer service credentials", it does say that the default assumed communication system is ISP1 and that specification does include those definitions. If the authentication mechanisms defined in ISP1 are used then the algorithms are fixed and the only thing that needs to be exchanged is the password.
 
However, use of ISP1 is not mandatory and even if ISP1 is used it is possible not to use the weak authentication mechanism provided by ISP1 (setting the authentication level to NONE) and rather relay on a strong authentication in an underlying transport or network layer - in that case the authentication information would not be included in the credentials parameter of the CSTS operation header, but I think the approach is nevertheless in line with the Recommendation. The parameters to be agreed by management will then depend very much on the options provided by the transport or network protocol and the mechanism implemented by the protocol.
 
Regards, Martin
 
________________________________

From: smwg-bounces at mailman.ccsds.org [mailto:smwg-bounces at mailman.ccsds.org] On Behalf Of John Pietras
Sent: 27 May 2010 19:21
To: CCSDS Service Mgmt WG; css-csts at mailman.ccsds.org
Subject: [Smwg] Issues regarding level of authentication and credentialsalogorithms for transfer services



SMWG and CSTSWG colleagues ---

In performing an analysis of all of the managed parameters needed for the MD-CSTS and TD-CSTS, I came across the following paragraphs in the latest draft of the CSTS Specification Framework:

 

3.2.4.2     Complex Management and Utilization Management shall agree on the level of authentication to be required for an association between a Service User and a Service Provider and shall configure both entities accordingly.

 

3.2.4.3     Complex Management and Utilization Management shall agree on the algorithm used to generate and check credentials parameters and shall make this algorithm known to the Service User and Service Provider together with associated parameters such as passwords or keys as necessary for the selected algorithm.

 

Similar  (service-specific) statements appear in each of the SLE transfer service specifcations. These requirements have impacts on the CSTS Framework, the SLE transfer service specification, and SCCS-SM. 

 

Regarding the CSTS Framework, these requirements are not reflected in the tables in annex H, "Interactions with Management", an should they probably should. I don't think this is important enough to delay Red-1, but it should be RIDded. 

 

Regarding the SLE transfer service specification, every specification has a table 3-1 that includes (among other things) the parameters that are to be configured via Service Management. Authentication level and identification of the credentails algorithm to be used should be added to table 3-1.  (Unfortunately, the SLE books have just been reissued, so it may be awhile before these updates are made.)

 

Regarding the Service Management specification, there is no mention of the authencation level in Blue-1. It should be added in Blue-2. The question is whether it should be specified on a per-service-instance basis, or on a Service Agreement basis (that is, the same authentical level applies to all transfer serivce instances within the context of a Service Agreement). 

 

Regarding credentials generation, section 1.3.5 (LIMITATIONS, CONSTRAINTS, EXCLUSIONS AND QUALIFICATIONS) of the SCCS-SM Blue-1 specification states "This Recommended Standard does not address the mechanism for exchanging authentication and access control information associated with the creation of transfer service credentials". This "covers" us as far as the SCCS-SM specification is concerned, but begs the question of how such information *is* exchanged. Do we need a standard method for such exchanges, or is leaving it bilaterally determined okay for now?

 

Best regards,

John

 

 


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