<p>Basically, because it doesn't make sense in the practical context that they wanted the theory to model.  In practice, you can't destroy something that doesn't exist; and we think of subjects as existing forever (you can't destroy them).</p>

CC BY-SA 3.0
2017-06-01T17:36:00.797Z
But there is also the operation destroy subject. And the thing that I want to destroy exists, but it is additionally to being an object although a subject, which means that destroying it as an object lets it loose its subjectness. (We employ the convention from the original paper that every subject is also an object)
Sebastian Bechtel
CC BY-SA 3.0
2017-06-01T17:14:03.307Z
2017-06-01T17:14:03.307Z
D.W.
<p>In the access control model HRU there is the primitive request destroy object o which is only defined if o is an object in the current protection state which is not a subject. I am interested in why this restriction is necessary/useful. </p>

<formal-methods><security><formal-systems>
semantics of "destroy object" in HRU model
Sebastian Bechtel
# semantics of "destroy object" in HRU model

(Asked by: username_0 on 2017-06-01)

In the access control model HRU there is the primitive request destroy object o which is only defined if o is an object in the current protection state which is not a subject. I am interested in why this restriction is necessary/useful.

**Tags:** formal-methods, security, formal-systems

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## 1 answers

### Answer by username_1 on 2017-06-01. Score: 0

Basically, because it doesn't make sense in the practical context that they wanted the theory to model. In practice, you can't destroy something that doesn't exist; and we think of subjects as existing forever (you can't destroy them).

> **Comments:**
> **username_0**: But there is also the operation destroy subject. And the thing that I want to destroy exists, but it is additionally to being an object although a subject, which means that destroying it as an object lets it loose its subjectness. (We employ the convention from the original paper that every subject is also an object)  

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