The following is my second comments on XACML Glossary.
I think XACML terms should be defined as common as possible.
One way to do that is to follow established standard as much as possible.
In my understanding, the international standard called 10181-3
Access Control Framework [1] seems to be the closest and the most
rigid standard for our access control domain.
I also think that it is ok to create a new term or borrow one from other
recommendations, but it should be limited to the case where the notion
we need to use means differently from the already defined one.
Considering from the above perspective, there are several terms
we should discuss further.
Principal:
The principal is defined in 10181-2: Authentication framework but not
in 10181-3: Access control framework. I think that the XACML definition
of Principal is not correct usage of Principal defined in 10181-2 meaning
authenticated requesting entity. But the definition of XACML refers to
the user portion of authorization policy. In this case, I think "Subject"
would be more appropriate term.
- I suggest to use "Subject" instead of "Principal."
(XACML definition keeps the current definition.)
Requester or Initiator:
I think that we need a term for an entity that attempts to access the
target resource. Principal written in XACML glossary does not mean that.
In [1], Initiator: an entity (e.g. human user or computer-based entity)
that
attempts to access other entities, is used. In SAML, Requester is used.
- I suggest to use "Initiator" or "Requester" to mean an entity (e.g. human
user or computer-based entity) that attempts to access other entities.
Resource:
In [1], "Target" is used: an entity to which access may be attempted.
But SAML uses "Resource" in their schema. I have no preference but
just resource could mean rather general in access control context.
- How about "Target Resource"?
Authorization policy:
Authorization policy component:
Authorization Decision:
Why do we prefer authorization to access control? Shorter?
In [1], Access Control Policy and Access Control Policy Rules
are used. The folloing is their definitions:
Access Control Policy in [1]: the set of rules that define the conditions
under
which an access may take place.
Access Control Policy Rules in [1]: security policy rules concerning the
provision of the access control service
The following is defined in [1] but not in XACML.
Clearance:
Initiator-bound access control information that can be compared with
security labels of targets.
SDA:
Security Domain Authority:
[1]: ISO/IEC 10181-3:1996, Information technology- Open Systems
Interconnection - Security Frameworks for open systems: Access control
framework
Michiharu Kudo