<s>
In	O
computer	B-General_Concept
science	I-General_Concept
,	O
an	O
oblivious	B-Data_Structure
data	I-Data_Structure
structure	I-Data_Structure
is	O
a	O
data	O
structure	O
that	O
gives	O
no	O
information	O
about	O
the	O
sequence	O
or	O
pattern	O
of	O
the	O
operations	O
that	O
have	O
been	O
applied	O
except	O
for	O
the	O
final	O
result	O
of	O
the	O
operations	O
.	O
</s>
<s>
And	O
in	O
the	O
outsourcing	B-Architecture
of	O
cloud	O
data	O
,	O
this	O
leakage	O
of	O
access	O
pattern	O
is	O
still	O
very	O
serious	O
.	O
</s>
<s>
Cloud	O
data	O
outsourcing	B-Architecture
:	O
When	O
writing	O
or	O
reading	O
data	O
from	O
a	O
cloud	O
server	B-Application
,	O
oblivious	B-Data_Structure
data	I-Data_Structure
structures	I-Data_Structure
are	O
useful	O
.	O
</s>
<s>
And	O
modern	O
databases	O
rely	O
on	O
data	O
structures	O
heavily	O
,	O
so	O
oblivious	B-Data_Structure
data	I-Data_Structure
structures	I-Data_Structure
come	O
in	O
handy	O
.	O
</s>
<s>
With	O
the	O
Oblivious	B-Data_Structure
data	I-Data_Structure
structure	I-Data_Structure
comes	O
in	O
practical	O
,	O
the	O
secure	O
processor	O
can	O
obfuscate	O
memory	O
access	O
pattern	O
in	O
a	O
provably	O
secure	O
manner	O
.	O
</s>
<s>
RAM-model	O
secure	O
computation	O
was	O
proposed	O
as	O
an	O
alternative	O
to	O
the	O
traditional	O
circuit	O
model	O
,	O
and	O
oblivious	B-Data_Structure
data	I-Data_Structure
structure	I-Data_Structure
is	O
used	O
to	O
prevent	O
information	O
access	O
behavioral	O
being	O
stolen	O
.	O
</s>
<s>
The	O
memory	O
access	O
of	O
oblivious	B-Application
RAM	I-Application
is	O
probabilistic	O
and	O
the	O
probabilistic	O
distribution	O
is	O
independent	O
of	O
the	O
input	O
.	O
</s>
<s>
In	O
the	O
paper	O
composed	O
by	O
Goldreich	O
and	O
Ostrovsky	O
have	O
theorem	O
to	O
oblivious	B-Application
RAM	I-Application
:	O
Let	O
denote	O
a	O
RAM	O
with	O
m	O
memory	O
locations	O
and	O
access	O
to	O
a	O
random	O
oracle	O
machine	O
.	O
</s>
<s>
Now	O
we	O
have	O
the	O
square-root	O
algorithm	O
to	O
simulate	O
the	O
oblivious	B-Application
ram	I-Application
working	O
.	O
</s>
<s>
To	O
access	O
original	O
RAM	O
in	O
t	O
steps	O
we	O
need	O
to	O
simulate	O
it	O
with	O
steps	O
for	O
the	O
oblivious	B-Application
RAM	I-Application
.	O
</s>
<s>
The	O
oblivious	O
tree	O
is	O
a	O
data	O
structure	O
similar	O
to	O
2-3	B-Data_Structure
Tree	I-Data_Structure
,	O
but	O
with	O
the	O
additional	O
property	O
of	O
being	O
oblivious	O
.	O
</s>
