<s>
The	O
HRU	B-Protocol
security	O
model	O
(	O
Harrison	O
,	O
Ruzzo	O
,	O
Ullman	O
model	O
)	O
is	O
an	O
operating	B-General_Concept
system	I-General_Concept
level	O
computer	O
security	O
model	O
which	O
deals	O
with	O
the	O
integrity	O
of	O
access	O
rights	O
in	O
the	O
system	O
.	O
</s>
<s>
The	O
HRU	B-Protocol
model	O
defines	O
a	O
protection	O
system	O
consisting	O
of	O
a	O
set	O
of	O
generic	O
rights	O
R	O
and	O
a	O
set	O
of	O
commands	O
C	O
.	O
An	O
instantaneous	O
description	O
of	O
the	O
system	O
is	O
called	O
a	O
configuration	O
and	O
is	O
defined	O
as	O
a	O
tuple	B-Application
of	O
current	O
subjects	O
,	O
current	O
objects	O
and	O
an	O
access	O
matrix	O
.	O
</s>
<s>
A	O
failing	O
operation	O
in	O
a	O
sequence	O
makes	O
the	O
whole	O
sequence	O
fail	O
,	O
a	O
form	O
of	O
database	B-General_Concept
transaction	I-General_Concept
.	O
</s>
