Re: [xacml] Draft BTG Profile

[David Chadwick <d.w.chadwick@kent.ac.uk>]

Hi John

thanks for your long explanation of the HL7 position.

Our BTG work has been done in conjunction with Porto's main hospital in
Portugal, along with the University of Porto. So it would appear that
some Europeans at least have a different interpretation of BTG to the US
work in HL7.

We have published a number of papers on BTG access in medical situations
and I will gladly send them to you if you wish.

The fundamental concept is this:

1. For any given resource, there are three classes of user as specified
in the access control policy
a) those who have permission to access the resource
b) those who are denied access to the resource
c) those who are normally denied access but may choose to BTG and gain
access if they deem it appropriate.

I would say that class c) users exactly fit your VIP record access
example below, and this is the class of user who are being dealt with in
this profile.

The profile is a generic profile and is not tied to health care
resources. It can be used in any scenario where they have the above
three classes of user

regards

David


On 23/11/2010 19:49, Davis, John M. wrote:
> David,
> 
> 1. BTG is a common healthcare concept. The Draft BTG profile seems to 
> describe a concept somewhat different. I've included a short paper which 
> provides definitions, descriptions and requirements for BTG and 
> "emergency access" as two distinct and different concepts within the 
> healthcare domain. Here is a short description from HL7's Access Control 
> Service Functional Model:
> 
> /"Break‐glass is named after the glass panel that protects a fire alarm. 
> Everyone in the building is authorized to use the fire alarm to report a 
> fire, but the ramifications of misuse are substantial. The fragile glass 
> panel is sufficient to avoid accidental triggering, and it forces the 
> user to stop and think/
> 
> /before acting. In the context of this document, a “Break Glass” 
> scenario involves a situation where the access control policy will 
> authorize the user to access certain information or functionality, but 
> only after the user attests that one or more relevant conditions exist."/
> 
> 2. As described in the draft profile, the most important concept is that 
> the profile requires a BTG permission. This does not match the notion of 
> BTG as used in healthcare which is much more like a user controlled 
> "gateway" much such as a fire alarm. I'll explain by means of a use case:
> 
> In this healthcare scenario, a user is authorized to access patient 
> records (has appropriate permissions). Some records (e.g., VIP) are 
> sequestered behind a BTG barrier. A user attempting to access a VIP 
> record will be presented with a warning banner indicating that the 
> record is protected and that access will subject the user to increased 
> auditing (and perhaps other controls such as notifications to system 
> admins). In any case, the requester has two options; 1) abort or 2) 
> continue. If 2) is chosen the record is presented. The distinguishing 
> characteristic is that no elevation of user permissions and no special 
> "BTG permission" is required, the user is already in the "clinician" 
> group authorized to view records. This is analogous to students in a 
> high school. They are all members of a group who are "authorized" to 
> pull the fire alarm. Doing so falsely will subject the student to 
> discipline but the student does not need the teachers authorization to 
> pull the alarm when conditions warrant.
> 
> This is distinguished from emergency access of the first kind (normal 
> emergency room operations). In emergency access #1, the context of the 
> emergency (significant harm or risk of death to the patient) needs to be 
> presented so that the access control system evaluates the appropriate 
> policy set (e.g. A clinician at one hospital may not be authorized 
> access to records at another under normal conditions of “treatment”). In 
> emergency access #1, the XSPA SAML attribute assertion profile provides 
> an "Emergency Access" purpose of use attribute. This purpose of use 
> allows the PDP to select and evaluate the appropriate policy for the 
> "emergency" condition as opposed to normal "treatment". Again, it is not 
> the user permissions that are evaluated but the fundamental context of 
> the policy environment.
> 
> There is emergency access of the second kind which is a variation of 
> emergency access #1. In emergency access #2, the requester makes the 
> request for information under the purpose of use of treatment and 
> clinical role. Authorization to view the record under these conditions 
> is denied (perhaps an underlying privacy policy is being enforced). In 
> response the clinician responds by elevating permissions by asserting 
> the “emergency role” in the XSPA SAML Assertion profile thereby 
> elevating privileges under the same POU of “treatment” and overriding 
> the original policy decision. In our work in HL7 we have found the 
> “emergency” role/permission unnecessary as POU has the added benefit of 
> putting in place (and managing) an emergency context vice a simple role. 
> Emergency #2 is probably closer to what is intended by the Draft BTG 
> profile but is significantly different from what is described above.
> 
> I believe additional discussion is warranted on the fundamental concepts 
> of the Draft BTG profile, first to ensure common understanding of the 
> different forms of access, the uses of policy, purpose of use and 
> permission and second to establish sound use cases that will 
> sufficiently clarify the purpose and conditions under which use of such 
> a profile is warranted.
> 
> Regards, Mike Davis, CISSP
> 
> Department of Veterans Affairs
> 
> Office of Health Information
> 
> Security Architect
> 
> 760-632-0294
> 
> -----Original Message-----
> From: David Chadwick [mailto:d.w.chadwick@kent.ac.uk]
> Sent: Tuesday, November 23, 2010 9:07 AM
> To: xacml
> Subject: [xacml] Draft BTG Profile
> 
> Dear List
> 
> about a year ago we discussed the standardisation of the Break The Glass 
> response (see Seth Proctor's message of 17 Dec 2009) and decided that a 
> profile to standardise the BTG response would be useful. Unfortunately 
> Seth left Sun before we got around to writing it.
> 
> Consequently Stijn Lievens and myself from Kent have produced a first 
> version (attached) for your consideration. I know its not in the correct 
> format yet, but we can fix that once the technical content has been agreed.
> 
> Comments appreciated
> 
> regards
> 
> David
> 
> -- 
> 
> *****************************************************************
> 
> David W. Chadwick, BSc PhD
> 
> Professor of Information Systems Security School of Computing, 
> University of Kent, Canterbury, CT2 7NF Skype Name: davidwchadwick
> 
> Tel: +44 1227 82 3221
> 
> Fax +44 1227 762 811
> 
> Mobile: +44 77 96 44 7184
> 
> Email: D.W.Chadwick@kent.ac.uk
> 
> Home Page: http://www.cs.kent.ac.uk/people/staff/dwc8/index.html
> 
> Research Web site: http://www.cs.kent.ac.uk/research/groups/iss/index.html
> 
> Entrust key validation string: MLJ9-DU5T-HV8J PGP Key ID is 0xBC238DE5
> 
> *****************************************************************
> 
> 
> 
> ---------------------------------------------------------------------
> To unsubscribe from this mail list, you must leave the OASIS TC that
> generates this mail.  Follow this link to all your TCs in OASIS at:
> https://www.oasis-open.org/apps/org/workgroup/portal/my_workgroups.php

-- 

*****************************************************************
David W. Chadwick, BSc PhD
Professor of Information Systems Security
School of Computing, University of Kent, Canterbury, CT2 7NF
Skype Name: davidwchadwick
Tel: +44 1227 82 3221
Fax +44 1227 762 811
Mobile: +44 77 96 44 7184
Email: D.W.Chadwick@kent.ac.uk
Home Page: http://www.cs.kent.ac.uk/people/staff/dwc8/index.html
Research Web site: http://www.cs.kent.ac.uk/research/groups/iss/index.html
Entrust key validation string: MLJ9-DU5T-HV8J
PGP Key ID is 0xBC238DE5

*****************************************************************