OASIS eXtensible Access Control Markup Language (XACML) TC

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Re: [xacml] [model] Proposal of Post Condition

  • 1.  Re: [xacml] [model] Proposal of Post Condition

    Posted 02-15-2002 02:05
    
    Yes. In your list of the terms, I prefer "provision" the most and
    "obligation" is the next. Do you think that "obligation" better describes
    the notion than "provision"?
    
    I think that how post-condition is specified and computed would be more
    debatable. Since v0.9 is available, I give a potential syntax below:
    
    <policyStatement>
      <target>
        <subjects>...
        <resources>...
        <actions>...
      </target>
      <policy>
        <predicate>...
      </policy>
      <post-condition>
        <onTrue>
          <operation uri="..."/>
        </onTrue>
        <onFalse>
          <operation uri="..."/>
        </onFalse>
      </post-condition>
    </policyStatement>
    
    The post-condition is computed:
    1. When the expression for <target> holds true, then the post-condition
    flag is set to on. Otherwise, this policy is not applicable and no
    post-condition is returned.
    
    2. If the post-condition flag is on and if <policy> is evaluated true, then
    the post-conditions in <onTrue> (if exists) is returned as the result of
    the computation. In case of no <onTrue>, no post-condition is returned.
    
    3. If the post-condition flag is on and If <policy> is evaluated as false,
    then the post-conditions in <onFalse> (if exists) is returned as the result
    of the computation. In case of no <onFalse>, no post-condition is returned.
    
    Does that make sense?
    
    Regards,
    Michiharu Kudo
    
    IBM Tokyo Research Laboratory, Internet Technology
    Tel. +81 (46) 215-4642   Fax +81 (46) 273-7428
    
    
    
    From: bill parducci <bill@parducci.net> on 2002/02/15 15:09
    
    To:   "XACML TC <xacml"
    cc:
    Subject:  Re: [xacml] [model] Proposal of Post Condition
    
    
    
    > Do you think that the term "post-condition" is not the right word?
    > If so, what do you think the best term for the notion of this kind?
    
    for me, one of the problems with the term 'post-condition' is that it
    technically refers to the *state* of something after an event, not
    something that must be done (as is the case with the term
    'pre-condition'). this can become confusing when working in other
    contexts (like UML: "Postconditions - Describe the state of the system,
    and perhaps the actors, after the use case is complete...")
    
    for starters, how about these?
    
    stipulation
    provision
    proviso
    constraint
    obligation
    
    caveat
    directive
    regulation
    
    i am sure we can come with a number of alternative terms that will work.
    personally, i like 'obligation', because in this model this is really
    what you have: the PEP has an obligation to enforce the rulings of the
    PDP (i.e. GRANT) under the terms defined by the PDP (e.g. 'delete after
    30 days') -- if it cannot it must DENY.
    
    does that make sense?
    
    b
    
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