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I
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5
7
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4586
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d
if
f
er
en
t
s
tep
s
i
n
d
etail,
an
d
th
e
ex
c
h
a
n
g
ed
m
ess
a
g
es.
Fin
a
ll
y
,
to
ex
p
lain
t
h
e
m
ain
s
ec
u
r
it
y
f
ea
t
u
r
es a
p
p
r
o
v
ed
b
y
o
u
r
co
n
tr
ib
u
tio
n
an
d
s
o
m
e
f
u
t
u
r
e
w
o
r
k
s
.
2.
L
I
T
E
R
AT
U
RE
R
E
VI
E
W
Secu
r
it
y
i
s
a
cr
u
cial
p
o
in
t
in
t
h
e
I
o
T
d
o
m
ai
n
,
a
lo
t
o
f
r
esear
ch
er
s
ar
e
w
o
r
k
i
n
g
to
p
r
o
p
o
s
e
a
s
o
lu
t
io
n
f
o
r
s
ec
u
r
in
g
ap
p
licatio
n
s
b
ase
d
o
n
a
co
n
s
tr
ai
n
ed
d
ev
ice.
T
h
e
b
ig
c
h
alle
n
g
e
is
to
ap
p
l
y
s
e
cu
r
it
y
f
ea
tu
r
es
s
u
c
h
as
au
t
h
en
t
icatio
n
a
n
d
au
t
h
o
r
izatio
n
to
v
er
if
y
t
h
e
co
n
f
i
d
en
tialit
y
,
in
te
g
r
it
y
,
an
d
av
ailab
ilit
y
o
f
d
ata
in
f
o
r
m
atio
n
.
So
m
e
au
t
h
o
r
s
p
r
o
p
o
s
e
a
s
o
lu
tio
n
b
ased
o
n
a
u
th
en
ticatio
n
li
k
e
t
h
e
au
th
o
r
s
B
ali
[
6
]
,
p
r
o
p
o
s
e
a
lig
h
t
w
ei
g
h
t
au
t
h
e
n
ticatio
n
m
ec
h
an
i
s
m
b
ased
o
n
a
ch
ao
tic
alg
o
r
ith
m
u
s
i
n
g
s
el
f
-
k
e
y
ag
r
ee
m
en
t
a
n
d
b
lo
ck
cip
h
er
to
i
m
p
r
o
v
e
th
e
MQ
T
T
s
ec
u
r
it
y
,
a
f
ter
s
i
m
u
la
tio
n
,
it
w
a
s
m
en
tio
n
ed
t
h
at
t
h
e
d
at
a
co
n
f
id
e
n
tialit
y
w
a
s
p
r
o
v
en
.
B
h
a
w
i
y
u
g
a
[
7
]
,
p
r
o
p
o
s
es
an
i
m
p
le
m
e
n
tatio
n
o
f
to
k
en
-
b
ased
a
u
th
e
n
tica
tio
n
o
f
MQ
T
T
p
r
o
to
co
l
in
co
n
s
tr
ain
ed
d
ev
ice
s
,
b
u
t
t
h
e
p
r
o
p
o
s
ed
d
esig
n
co
n
s
is
t
s
o
f
f
o
u
r
co
m
p
o
n
e
n
ts
:
P
u
b
lis
h
er
,
s
u
b
s
cr
ib
er
,
MQ
T
T
b
r
o
k
er
,
an
d
T
o
k
en
au
t
h
e
n
tic
ati
o
n
s
er
v
er
.
R
ah
m
a
n
[
8
]
th
e
au
th
o
r
s
p
r
o
p
o
s
e
a
s
ec
u
r
e
v
e
r
s
io
n
d
esi
g
n
ed
f
o
r
w
ir
ele
s
s
s
en
s
o
r
n
et
w
o
r
k
s
b
y
d
ev
elo
p
in
g
a
m
u
lti
-
tier
a
u
t
h
e
n
ticatio
n
s
y
s
te
m
to
e
n
s
u
r
e
d
ata
p
r
iv
ac
y
i
n
I
o
T
s
y
s
te
m
d
ep
en
d
in
g
o
n
th
e
u
s
e
o
f
cip
h
er
tex
t
-
p
o
lic
y
attr
i
b
u
te
-
b
ased
e
n
cr
y
p
tio
n
(
C
P
-
A
B
E
)
o
r
k
e
y
-
p
o
lic
y
attr
ib
u
te
-
b
a
s
ed
en
cr
y
p
tio
n
(
K
P
-
A
B
E
)
w
it
h
th
e
li
g
h
t
w
ei
g
h
t
ellip
tic
cu
r
v
e
cr
y
p
to
g
r
ap
h
y
(
E
C
C
)
.
Oth
er
w
o
r
k
s
ar
e
b
ased
o
n
au
t
h
o
r
izatio
n
m
ec
h
a
n
is
m
to
s
ec
u
r
e
th
e
p
r
o
to
co
l
MQ
T
T
as
:
Nir
u
n
ta
s
u
k
r
at
[
9
]
th
eir
s
o
lu
tio
n
is
b
ased
o
n
O.
Au
t
h
1
.
0
a
an
o
p
e
n
au
th
o
r
iz
atio
n
s
ta
n
d
ar
d
f
o
r
w
eb
ap
p
licatio
n
s
,
t
h
e
p
r
o
p
o
s
e
d
s
y
s
te
m
is
b
a
s
ed
o
n
a
s
et
o
f
cr
e
d
en
tials
(
d
ev
ice
I
D,
d
ev
ice
s
e
cr
et,
ac
ce
s
s
to
k
e
n
,
a
n
d
ac
ce
s
s
to
k
en
s
ec
r
et
)
,
s
o
m
e
o
f
th
e
s
e
cr
ed
en
tials
n
ee
d
to
b
e
s
en
t t
h
r
o
u
g
h
a
d
ev
ice
w
h
ic
h
h
as to
b
e
n
o
t c
o
n
s
tr
ain
e
d
an
d
ca
n
af
f
o
r
d
HT
T
P
S.
Oth
er
au
t
h
o
r
s
p
r
o
p
o
s
e
a
cr
y
p
t
o
g
r
ap
h
ic
alg
o
r
ith
m
to
s
ec
u
r
e
MQ
T
T
p
r
o
to
c
o
l
lik
e
in
[
1
0
]
th
e
y
p
r
o
p
o
s
e
a
co
m
p
o
s
ite
s
ec
u
r
it
y
s
o
lu
t
io
n
f
o
r
MQ
T
T
b
y
co
m
b
i
n
i
n
g
o
n
A
ttrib
u
te
-
b
ased
en
cr
y
p
ti
o
n
an
d
ad
v
an
ce
d
en
cr
y
p
tio
n
s
ta
n
d
ar
d
(
A
E
S)
S
-
b
o
x
es.
T
h
e
s
o
lu
t
io
n
i
s
b
as
ed
o
n
p
u
b
lic
-
k
e
y
cr
y
p
to
g
r
ap
h
y
an
d
s
ec
r
et
-
k
e
y
cr
y
p
to
g
r
ap
h
y
,
s
o
d
o
u
b
le
d
ec
r
y
p
t
io
n
m
u
s
t
b
e
d
o
n
e
b
y
th
e
s
u
b
s
cr
ib
er
.
W
e
w
ill
h
a
v
e
t
h
e
s
a
m
e
d
r
a
w
b
ac
k
m
o
r
e
o
v
er
h
ea
d
.
An
o
th
er
s
o
lu
t
io
n
b
ased
o
n
attr
ib
u
tes
is
[
1
1
]
Sin
g
h
p
r
o
p
o
s
e
a
n
e
w
s
ec
u
r
e
p
u
b
lis
h
co
m
m
an
d
“
SP
u
b
li
s
h
”
f
o
r
(
MQ
T
T
,
MQ
T
T
-
SN)
w
h
ic
h
e
n
cr
y
p
t
d
ata
b
as
ed
o
n
a
s
et
o
f
attr
ib
u
te
-
b
ased
en
cr
y
p
tio
n
(
A
B
E
)
,
th
e
k
e
y
p
o
lic
y
KP
-
A
B
E
an
d
a
cip
h
er
tex
t
p
o
lic
y
CP
-
A
B
E
u
s
in
g
l
ig
h
t
w
ei
g
h
t
E
C
C
,
th
e
u
s
e
o
f
C
P
-
A
B
E
ca
u
s
e
s
an
e
x
tr
a
o
v
er
h
ea
d
w
h
ic
h
i
s
t
h
e
m
ai
n
d
r
a
w
b
ac
k
o
f
u
s
i
n
g
AB
E
.
Me
k
to
u
b
i
[
1
2
]
th
eir
co
n
t
r
ib
u
tio
n
i
s
to
s
ec
u
r
e
th
e
f
lo
w
o
f
d
is
tr
ib
u
ted
m
es
s
a
g
es
b
et
w
ee
n
t
h
e
u
s
er
s
o
f
th
e
MQ
T
T
p
r
o
to
c
o
l
b
y
u
s
i
n
g
a
ce
r
tif
icatio
n
au
t
h
o
r
it
y
th
at
g
e
n
er
ates
a
p
r
iv
ate
k
e
y
a
n
d
a
ce
r
ti
f
icate
to
a
to
p
ic
t
h
at
is
p
u
b
li
s
h
ed
f
o
r
ce
r
ti
f
ie
d
clie
n
ts
.
T
h
e
co
n
tr
ib
u
tio
n
in
[
1
3
]
p
r
o
p
o
s
es
to
s
ec
u
r
e
MQ
T
T
b
y
u
s
i
n
g
ac
ce
s
s
co
n
tr
o
l
lis
ts
(
AC
L
s
)
e
m
b
ed
d
ed
in
a
Mo
s
q
u
itto
b
r
o
k
er
w
h
ic
h
ac
ts
lik
e
a
f
il
ter
allo
w
i
n
g
o
n
l
y
th
o
s
e
d
ata
w
h
ic
h
ar
e
r
eq
u
ested
th
er
eb
y
s
av
in
g
th
e
f
lo
w
o
f
a
m
b
i
g
u
o
u
s
d
ata.
T
h
e
(
A
C
L
)
m
e
th
o
d
ac
t
a
s
ex
tr
a
s
ec
u
r
it
y
to
t
h
e
w
h
o
le
p
r
o
ce
s
s
,
f
o
r
ea
ch
d
ata
u
s
er
n
a
m
e
an
d
p
ass
w
o
r
d
,
ar
e
cr
ea
ted
to
g
et
ac
ce
s
s
to
th
e
d
a
ta.
Ho
w
e
v
er
,
th
i
s
s
o
lu
tio
n
ca
n
ca
u
s
e
m
o
r
e
o
v
er
h
ea
d
,
s
ca
lin
g
w
ith
t
h
e
n
u
m
b
e
r
o
f
d
if
f
er
e
n
t
d
ata
to
b
e
tr
an
s
m
itted
.
T
w
o
w
o
r
k
s
ar
e
lik
e
o
u
r
s
o
lu
tio
n
b
ased
o
n
au
g
m
e
n
ted
p
ass
w
o
r
d
-
o
n
l
y
au
th
e
n
tica
tio
n
an
d
k
e
y
ex
c
h
a
n
g
e
(
Au
g
P
A
KE
)
ar
e:
Sh
i
n
[
1
4
]
,
th
e
s
o
lu
tio
n
ca
lled
Au
g
M
QT
T
:
A
s
ess
io
n
k
e
y
w
il
l
b
e
estab
lis
h
ed
b
et
w
ee
n
th
e
p
u
b
lis
h
er
an
d
th
e
b
r
o
k
er
an
d
an
o
th
er
s
e
s
s
io
n
b
et
w
ee
n
th
e
b
r
o
k
er
an
d
th
e
s
u
b
s
cr
ib
er
w
it
h
o
u
t
ce
r
ti
f
ica
ti
o
n
s
.
T
o
p
u
b
lis
h
a
m
es
s
ag
e,
th
e
p
u
b
li
s
h
er
u
s
e
s
a
s
ec
u
r
e
s
y
m
m
etr
ic
-
k
e
y
en
cr
y
p
tio
n
s
c
h
e
m
a
o
r
a
s
ec
u
r
e
au
th
en
ticated
en
cr
y
p
tio
n
w
it
h
as
s
o
ciate
d
d
ata
s
ch
e
m
a
to
s
en
d
d
ata
to
th
e
b
r
o
k
er
,
th
e
b
r
o
k
er
u
s
e
s
th
e
s
a
m
e
k
e
y
to
d
ec
r
y
p
t
d
ata
a
n
d
s
to
r
e
t
h
e
d
ata
m
e
s
s
a
g
e,
f
o
r
n
e
ce
s
s
ar
y
r
eq
u
e
s
t
t
h
e
b
r
o
k
er
tr
an
s
m
its
a
cip
h
er
tex
t
to
th
e
s
u
b
s
cr
ib
er
u
s
in
g
t
h
e
s
a
m
e
k
e
y
s
h
ar
ed
w
ith
th
e
b
r
o
k
er
.
T
h
e
p
r
o
p
o
s
ed
s
o
lu
tio
n
is
i
m
p
le
m
e
n
ted
th
r
o
u
g
h
Mo
s
q
u
itto
.
C
alab
r
etta
[
1
5
]
MQ
T
T
-
A
u
t
h
t
h
e
a
u
th
o
r
s
u
s
e
t
h
e
Au
g
P
A
KE
p
r
o
to
co
l
to
m
ak
e
t
h
e
s
e
s
s
io
n
k
e
y
a
n
d
u
s
e
an
a
u
t
h
e
n
ticatio
n
to
k
en
w
i
ch
cr
ea
te
a
n
d
p
u
b
lis
h
o
n
a
ce
r
tai
n
to
p
ic
an
d
an
au
t
h
o
r
izatio
n
to
k
en
s
h
ar
ed
b
etw
ee
n
t
h
e
p
u
b
lis
h
er
an
d
s
o
m
ec
h
o
s
en
s
u
b
s
cr
ib
er
s
.
T
h
e
s
o
lu
tio
n
u
s
e
s
A
cti
v
eM
Q.
T
h
is
T
ab
le
1
m
a
k
es
a
co
m
p
ar
i
s
o
n
b
et
w
ee
n
s
o
m
e
p
r
o
p
o
s
ed
s
o
lu
tio
n
s
to
s
ec
u
r
e
MQ
T
T
b
y
g
i
v
i
n
g
s
o
m
e
ad
v
a
n
ta
g
es a
n
d
d
r
a
w
b
ac
k
s
f
o
r
ea
ch
o
n
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[
1
4
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A
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[
1
5
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lic
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[
1
9
]
.
MQ
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[
2
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1
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(
O
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)
[
2
1
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.
I
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itab
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ap
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licatio
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es
o
f
t
h
e
MQ
T
T
p
r
o
to
co
l:
I
t’
s
a
p
u
b
lis
h
ed
/
s
u
b
s
cr
ib
e
p
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o
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l
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d
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C
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/I
P
.
I
t'
s
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ited
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ain
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ir
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e
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lic
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en
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r
ce
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t
also
s
u
p
p
o
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ts
th
r
ee
lev
e
ls
o
f
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u
alit
y
o
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er
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ice
(
Qo
S).
I
n
MQ
T
T
,
th
e
p
u
b
lis
h
-
s
u
b
s
cr
i
b
e
m
o
d
el
m
e
n
tio
n
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b
elo
w
i
n
Fig
u
r
e
1
,
th
e
p
u
b
lis
h
er
s
e
n
d
s
th
e
d
ata
to
th
e
b
r
o
k
er
f
o
r
p
u
b
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h
i
n
g
in
th
e
‘
P
u
b
lis
h
’
m
e
s
s
a
g
e;
a
s
u
b
s
cr
i
b
er
au
th
e
n
ticates
a
n
d
s
u
b
s
cr
ib
es
to
th
e
b
r
o
k
er
f
o
r
Evaluation Warning : The document was created with Spire.PDF for Python.
I
SS
N
:
2
0
8
8
-
8708
I
n
t J
E
lec
&
C
o
m
p
E
n
g
,
Vo
l.
11
,
No
.
5
,
Octo
b
e
r
2
0
2
1
:
4
5
7
7
-
4586
4580
a
ce
r
tain
to
p
ic
o
n
th
e
‘
Su
b
s
c
r
ib
e’
m
es
s
ag
e,
t
h
e
b
r
o
k
er
s
en
d
s
th
e
d
ata
to
th
e
s
p
ec
if
ics
s
u
b
s
cr
ib
er
s
th
at
ar
e
s
u
b
s
cr
ib
ed
to
th
e
s
p
ec
i
f
ic
to
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ic
o
n
‘
P
u
b
lis
h
’
m
e
s
s
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g
e.
3
.
2
.
T
he
Aug
P
AK
E
pro
t
o
co
l
T
h
e
Au
g
P
A
KE
p
r
o
to
co
l
[
1
8
]
is
b
ased
o
n
th
e
m
o
d
i
f
icatio
n
o
f
t
h
e
Dif
f
ie
Hell
m
a
n
k
e
y
ex
c
h
an
g
e
p
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o
to
co
l.
I
n
th
is
p
r
o
to
co
l,
th
e
clien
t
co
m
p
u
tes
a
k
e
y
f
r
o
m
t
h
e
p
ass
w
o
r
d
to
au
th
e
n
tica
te
t
o
th
e
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er
v
er
w
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ic
h
d
o
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n
o
t
n
ee
d
to
s
to
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e
clie
n
t
p
ass
w
o
r
d
s
.
Af
ter
s
u
cc
e
s
s
f
u
l
a
u
t
h
en
t
icatio
n
,
th
e
s
ec
u
r
e
s
es
s
io
n
is
estab
li
s
h
ed
a
n
d
k
e
y
a
g
r
ee
m
en
t
b
et
w
ee
n
t
h
e
clien
t
a
n
d
th
e
s
er
v
er
.
T
h
e
Au
g
P
A
KE
p
r
o
to
co
l
ex
ch
a
n
g
es
4
m
es
s
ag
e
s
.
T
h
e
Au
g
m
e
n
ted
i
s
a
clie
n
t
-
s
er
v
e
r
s
ess
io
n
k
e
y
e
s
tab
lis
h
m
en
t
p
r
o
to
co
l
th
at
u
s
es
s
o
m
e
p
ar
a
m
ete
r
s
w
h
ich
ar
e
ex
p
lain
ed
i
n
th
i
s
T
ab
le
2
.
T
ab
le
2
.
Descr
ip
tio
n
o
f
d
if
f
er
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n
t v
ar
iab
les
V
a
r
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a
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D
e
scri
p
t
i
o
n
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T
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y
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e
r
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t
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o
f
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p
A
p
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i
me
n
u
m
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su
c
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a
s
p
=
a
q
+
1
,
w
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t
h
a
n
i
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e
g
e
r
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sh
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i
o
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a
b
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e
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t
i
f
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e
r
||
Ju
x
t
a
p
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t
i
o
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o
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c
o
n
c
a
t
e
n
a
t
i
o
n
o
f
st
r
i
n
g
s
Fig
u
r
e
1
.
P
u
b
lis
h
-
s
u
b
s
cr
ib
e
m
o
d
el
T
h
e
A
u
g
P
AKE
alg
o
r
ith
m
co
n
s
i
s
ts
o
f
t
w
o
-
p
h
a
s
e:
th
e
i
n
it
i
aliza
tio
n
p
h
ase
a
n
d
th
e
ac
t
u
a
l
p
r
o
to
c
o
l
ex
ec
u
t
io
n
:
T
h
e
A
u
g
P
AKE
A
lg
o
r
it
h
m
inputs
: C: client identifier w: client's password S: Server identifier
initialization:
client C
computes
=
′
(1)
w
here
′
=
(
‖
‖
)
client C
send (C, W) to server S
client C
chooses
and computes
=
(2)
client
C send (C,X) to server S
traitement:
if server
S
received X equal to 0,1 or
-
1 (mod p)
server S
discards the session
i
f not
server S
chooses
and computes
=
(
)
(3)
where
=
′
(
′′
01''
∥
∥
∥
)
server S send (S, Y) to the client C
if
client C
received Y equal to 0,1 or
-
1 (mod p)
client C
terminates the protocol execution
If not
client C
computes
=
(4)
where
=
1
+
′
=
′
(
′′
01''
,
,
,
)
and
=
(
′
′
02
′
′
‖
‖
‖
‖
‖
)
(5)
client C sent Vc to server S
if
server S
receives
≠
(
′
′
02
′
′
‖
‖
‖
‖
‖
)
with K
=
(6)
server S
stops the procedure
if not
server S
generates an authenticator
=
(
"
03
"
‖
‖
‖
‖
‖
)
(7)
server S sends Vs to client C
server S
computes the session key
=
(
′′
04
′′
‖
‖
‖
‖
‖
)
(8)
if
c
lient C
receives
Vs
≠
(
"
03
"
‖
‖
‖
‖
‖
)
client C
terminates the procedure
if not
Client C
computes
=
(
′′
04
′
′
‖
‖
‖
‖
‖
)
Evaluation Warning : The document was created with Spire.PDF for Python.
I
n
t J
E
lec
&
C
o
m
p
E
n
g
I
SS
N:
2
0
8
8
-
8708
MQTT
-
P
R
E
S
E
N
T:
a
p
p
r
o
a
ch
t
o
s
ec
u
r
e
in
tern
et
o
f th
in
g
s
a
p
p
lica
tio
n
s
u
s
in
g
MQTT
...
(
I
ma
n
e
S
a
h
mi)
4
581
3
.
3
.
P
RE
SE
NT
Af
ter
s
ec
u
r
e
k
e
y
s
es
s
io
n
e
s
t
ab
lis
h
m
e
n
t,
w
e
w
il
l
u
s
e
t
h
e
p
ay
lo
ad
en
cr
y
p
tio
n
en
ca
p
s
u
lated
in
to
P
UB
L
I
SH
m
es
s
ag
e.
E
n
cr
y
p
tio
n
lik
e
a
tec
h
n
iq
u
e
o
f
cr
y
p
to
g
r
ap
h
y
w
h
ich
i
s
th
e
s
cie
n
ce
o
f
p
r
o
tectin
g
d
ata
f
r
o
m
m
alicio
u
s
ac
t
s
to
en
s
u
r
e
t
h
e
c
o
n
f
id
e
n
tialit
y
,
i
n
teg
r
i
t
y
,
a
n
d
au
th
e
n
tic
it
y
o
f
t
h
e
tr
an
s
m
itted
in
f
o
r
m
a
tio
n
.
I
n
t
h
is
p
er
s
p
ec
tiv
e,
u
s
in
g
t
h
e
cr
y
p
t
o
g
r
ap
h
ic
tech
n
iq
u
e
is
a
n
i
n
telli
g
e
n
t
ch
o
ice
to
b
e
d
ev
elo
p
ed
to
s
u
p
p
o
r
t
h
eter
o
g
e
n
eit
y
,
i
n
ter
o
p
er
ab
ilit
y
,
k
e
y
s
ize,
lo
w
e
n
er
g
y
co
n
s
u
m
p
tio
n
,
li
m
ited
r
eso
u
r
ce
s
o
f
I
o
T
d
ev
ices
[
2
2
]
.
T
h
at’
s
w
h
y
,
w
e
u
s
e
P
R
E
SE
NT
[
2
3
]
en
cr
y
p
tio
n
as
a
lig
h
t
w
ei
g
h
t
b
lo
ck
cip
h
er
,
co
m
p
ar
ed
to
A
E
S
,
it’
s
2
,
5
s
m
al
ler
t
h
an
t
h
e
la
s
t
o
n
e.
I
t
’
s
a
n
e
x
a
m
p
le
o
f
t
h
e
SP
-
Net
w
o
r
k
cr
y
p
to
g
r
ap
h
ic
al
g
o
r
ith
m
.
I
t
co
n
s
i
s
ts
o
f
3
2
r
o
u
n
d
s
,
t
h
e
b
lo
c
k
le
n
g
th
is
6
4
b
its
a
n
d
t
w
o
s
u
p
p
o
r
ted
k
e
y
le
n
g
t
h
s
o
f
8
0
an
d
1
2
8
b
its
as
s
h
o
w
n
i
n
Fig
u
r
e
2
,
t
h
e
p
r
o
ce
d
u
r
e
o
f
en
cr
y
p
tio
n
is
d
iv
id
ed
in
to
th
r
ee
p
h
ases
:
a.
Ke
y
ad
d
itio
n
:
t
h
e
d
ata
u
n
d
er
g
o
es
a
x
o
r
o
p
er
atio
n
w
it
h
t
h
e
k
e
y
f
r
o
m
w
h
ic
h
o
n
l
y
t
h
e
la
s
t
6
4
b
its
o
f
th
e
r
esu
lt
ar
e
ta
k
en
f
o
r
t
h
is
o
p
er
atio
n
.
A
f
ter
t
h
i
s
,
th
e
6
4
b
its
d
at
a
is
d
iv
id
ed
in
to
1
6
b
lo
ck
s
ea
ch
co
n
tai
n
i
n
g
1
6
b
its
f
o
r
th
e
n
ex
t p
r
o
ce
s
s
.
b.
No
n
-
l
in
ea
r
s
u
b
s
t
itu
tio
n
la
y
er
:
E
ac
h
o
f
t
h
i
s
b
lo
ck
is
th
e
n
p
as
s
ed
th
r
o
u
g
h
th
e
s
u
b
s
tit
u
tio
n
b
o
x
es
w
h
er
e
th
e
v
alu
e
i
n
t
h
ese
b
o
x
es a
r
e
r
ep
lace
d
b
y
th
e
v
al
u
es i
n
t
h
e
s
u
b
s
tit
u
tio
n
b
lo
ck
s
.
c.
B
it
-
w
is
e
p
er
m
u
tatio
n
:
T
h
e
s
u
b
s
titu
ted
d
ata
i
s
t
h
e
n
p
ass
ed
t
h
r
o
u
g
h
t
h
e
p
er
m
u
ta
tio
n
b
lo
ck
w
h
er
e
all
th
e
6
4
b
its
o
f
th
e
in
p
u
t
d
at
a
ar
e
r
e
o
r
g
an
ized
.
Af
ter
th
i
s
,
th
e
k
e
y
is
u
p
d
ated
to
p
r
o
d
u
ce
an
o
th
er
r
o
u
n
d
k
e
y
w
h
ic
h
is
u
s
ed
n
ex
t
ti
m
e
th
e
s
a
m
e
e
n
tir
e
p
r
o
ce
s
s
is
r
ep
ea
ted
f
o
r
th
e
s
a
m
e
s
et
o
f
d
ata.
T
h
is
i
s
r
ep
ea
t
ed
3
2
ti
m
es
an
d
th
en
t
h
e
e
n
cr
y
p
ted
d
ata
is
tr
an
s
m
i
tted
.
d.
P
R
E
SENT
A
lg
o
r
ith
m
ge
n
er
ate
R
o
u
n
d
Ke
y
s
(
)
f
o
r
i=1
to
3
1
do
ad
d
R
o
u
n
d
Ke
y
(
ST
A
T
E
;K
i
)
s
B
o
x
L
a
y
er
(
ST
A
T
E
)
p
L
a
y
er
(
ST
A
T
E
)
end f
o
r
a
d
d
R
ound
Ke
y
(
ST
A
T
E,
K
32
)
Fig
u
r
e
2
.
A
l
g
o
r
ith
m
d
escr
ip
tio
n
o
f
P
R
E
SENT
[
2
3
]
4.
T
H
E
P
RO
P
O
SE
D
AP
P
RO
A
CH
Ou
r
ap
p
r
o
ac
h
to
s
ec
u
r
e
t
h
e
MQ
T
T
p
r
o
to
c
o
l
co
n
s
is
t
s
o
f
u
s
i
n
g
t
h
e
Au
g
P
A
KE
alg
o
r
ith
m
w
it
h
P
R
E
SENT
as
lig
h
t
w
ei
g
h
t
e
n
cr
y
p
t
io
n
f
o
r
t
h
e
p
a
y
lo
ad
o
f
P
UB
L
I
SH
m
e
s
s
a
g
e.
O
u
r
co
n
tr
ib
u
ti
o
n
r
elate
d
to
Au
g
-
MQ
T
T
is
to
b
r
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ai
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ay
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it’
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ata
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ec
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e
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g
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l
ain
te
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also
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n
Evaluation Warning : The document was created with Spire.PDF for Python.
I
SS
N
:
2
0
8
8
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8708
I
n
t J
E
lec
&
C
o
m
p
E
n
g
,
Vo
l.
11
,
No
.
5
,
Octo
b
e
r
2
0
2
1
:
4
5
7
7
-
4586
4582
MQ
T
T
-
Au
t
h
,
th
e
a
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h
o
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m
e
n
tio
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ed
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at
t
h
e
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k
er
co
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l
d
b
e
a
s
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g
le
p
o
in
t
o
f
attac
k
.
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t
h
as
co
m
p
lete
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is
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il
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y
o
f
th
e
e
x
ch
a
n
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ed
d
ata
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ec
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s
e
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n
ch
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en
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r
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ased
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g
P
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ir
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te
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is
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ased
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n
th
e
A
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g
P
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alg
o
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it
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m
t
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estab
lis
h
a
s
ec
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r
e
k
e
y
s
e
s
s
i
o
n
b
et
w
ee
n
th
e
p
u
b
li
s
h
er
/t
h
e
s
u
b
s
cr
ib
er
an
d
th
e
b
r
o
k
er
.
I
t’
s
d
iv
id
ed
in
to
t
w
o
p
h
ase
s
:
a.
T
h
e
in
itial
izatio
n
p
h
ase
:
th
e
p
u
b
lis
h
er
s
e
n
d
s
(
C
p
,
W
p
)
t
o
th
e
b
r
o
k
er
w
h
er
e
C
p
:
t
h
e
i
d
en
tifie
r
o
f
th
e
p
u
b
lis
h
er
a
n
d
co
m
p
u
ted
W
p
b
y
u
s
in
g
t
h
e
(
1
)
in
th
e
Au
g
P
A
K
E
alg
o
r
ith
m
:
b.
T
h
e
ex
ec
u
tio
n
p
h
a
s
e
<P
u
b
lis
h
er
--
B
r
o
k
er
>:
co
m
p
o
s
ed
o
f
m
u
lt
ip
le
s
tep
s
m
e
n
tio
n
ed
b
elo
w
i
n
F
ig
u
r
e
3
,
th
at
ex
p
lai
n
t
h
e
Ke
y
s
es
s
io
n
b
et
w
ee
n
t
h
e
P
u
b
lis
h
er
an
d
th
e
B
r
o
k
er
:
1)
T
h
e
p
u
b
lis
h
er
s
en
d
s
(
C
p
,X
p
)
to
th
e
b
r
o
k
er
ac
co
r
d
in
g
to
(
2
)
.
2)
T
h
e
b
r
o
k
er
s
en
d
s
(
S,
Y
p
)
to
th
e
p
u
b
lis
h
er
w
h
en
it r
ec
ei
v
ed
t
h
e
r
ig
h
t X
p
; a
cc
o
r
d
in
g
to
(
3
)
.
3)
T
h
e
p
u
b
lis
h
er
s
en
d
s
(
C
p
,
Vcp
)
; a
cc
o
r
d
in
g
to
(
5
)
;
w
h
e
n
it r
ec
eiv
ed
th
e
r
i
g
h
t Y
p
.
4)
T
h
e
b
r
o
k
er
co
m
p
u
tes S
K
p
ac
co
r
d
in
g
to
(
8
)
an
d
s
en
d
s
(
S,
V
sp
)
,
ac
co
r
d
in
g
to
(
7
)
.
5)
Fin
all
y
,
th
e
p
u
b
li
s
h
er
co
m
p
u
t
es
SKP
;
ac
co
r
d
in
g
to
(
8
)
,
w
h
en
it’s
r
ec
eiv
ed
th
e
r
ig
h
t
Vsp
.
T
h
e
p
u
b
lis
h
er
an
d
th
e
b
r
o
k
er
s
h
ar
e
a
s
ec
u
r
e
s
ess
io
n
k
e
y
SKp
.
c.
T
h
e
ex
ec
u
tio
n
p
h
a
s
e
<B
r
o
k
er
--
S
u
b
s
cr
ib
er
>
:
co
m
p
o
s
ed
o
f
m
u
lt
ip
le
s
tep
s
m
e
n
tio
n
ed
b
elo
w
i
n
F
ig
u
r
e
4
,
th
at
ex
p
lai
n
t
h
e
Ke
y
s
es
s
io
n
b
et
w
ee
n
t
h
e
B
r
o
k
er
an
d
th
e
S
u
b
s
cr
ib
er
:
1)
T
h
e
Su
b
s
cr
ib
er
s
en
d
s
(
C
s
,
X
s
)
to
th
e
b
r
o
k
er
ac
co
r
d
in
g
to
(
2
)
.
2)
T
h
e
b
r
o
k
er
s
en
d
s
(
S,
Y
s
)
to
th
e
Su
b
s
cr
ib
er
w
h
e
n
it r
ec
eiv
ed
th
e
r
ig
h
t X
s
; a
cc
o
r
d
in
g
to
(
3
)
.
3)
T
h
e
Su
b
s
cr
ib
er
s
en
d
s
(
C
s
,V
cs
)
;
ac
co
r
d
in
g
to
(
5
)
; w
h
e
n
it r
ec
eiv
ed
th
e
r
i
g
h
t Y
s
.
4)
T
h
e
b
r
o
k
er
co
m
p
u
tes S
Ks ac
c
o
r
d
in
g
to
(
8
)
an
d
s
en
d
s
(
S,
Vs
s
)
,
ac
co
r
d
in
g
to
(
7
)
.
5)
Fin
all
y
,
t
h
e
Su
b
s
cr
ib
er
co
m
p
u
tes
SK
s
;
ac
co
r
d
in
g
to
(
8
)
,
w
h
e
n
it’s
r
ec
eiv
ed
th
e
r
i
g
h
t
Vss
.
T
h
e
Su
b
s
cr
ib
er
an
d
th
e
b
r
o
k
er
s
h
ar
e
s
ec
u
r
e
s
e
s
s
io
n
k
e
y
S
k
s
.
T
h
e
b
r
o
k
er
h
as
th
e
t
w
o
s
e
s
s
io
n
s
k
e
y
s
s
h
ar
ed
b
y
th
e
s
u
b
s
cr
ib
er
an
d
th
e
p
u
b
li
s
h
er
as
ar
e
m
e
n
tio
n
ed
i
n
Fig
u
r
e
5
,
I
t c
o
m
p
u
te
s
t
h
e
k
e
y
K
s
b
y
t
h
e
(
9
)
:
=
⊕
(
9
)
T
h
e
k
e
y
K
s
m
u
s
t
b
e
s
h
ar
ed
with
t
h
e
p
u
b
lis
h
er
an
d
th
e
s
u
b
s
cr
ib
er
th
at’
s
w
h
y
t
h
e
b
r
o
k
er
s
en
d
s
t
h
e
k
e
y
to
t
h
e
p
u
b
lis
h
er
(
s
u
b
s
cr
ib
er
)
b
y
P
R
E
SENT
en
cr
y
p
tio
n
u
s
in
g
t
h
e
Sk
p
(
Sk
s
)
.
B
o
th
th
e
p
u
b
li
s
h
er
an
d
th
e
s
u
b
s
cr
ib
er
h
av
e
t
h
e
s
h
ar
ed
k
e
y
K
s
.
W
h
e
n
t
h
e
p
u
b
lis
h
er
w
a
n
ts
to
p
u
b
li
s
h
a
m
ess
a
g
e,
t
h
e
P
R
E
SENT
en
cr
y
p
tio
n
p
r
o
ce
s
s
ap
p
lied
to
th
e
p
ay
lo
ad
o
f
t
h
e
m
es
s
ag
e
P
UB
L
I
S
H
u
s
i
n
g
K
s
,
th
e
p
u
b
li
s
h
er
w
il
l
tr
an
s
m
it
E
(
Ks,
Da
ta
1
)
to
th
e
b
r
o
k
er
.
W
h
en
n
ec
ess
ar
y
/r
eq
u
ested
,
B
r
o
k
er
tr
an
s
m
its
a
cip
h
er
tex
t
E
(
K
S
,
Da
ta
1
)
to
Su
b
s
cr
ib
er
,
w
h
o
ca
n
d
ec
r
y
p
t b
y
P
R
E
SENT
d
ec
r
y
p
t
io
n
w
it
h
th
e
k
e
y
K
S
to
g
e
t th
e
m
es
s
ag
e
p
u
b
lis
h
ed
ac
co
r
d
in
g
t
o
its
co
r
r
esp
o
n
d
in
g
to
p
ic.
Fig
u
r
e
3
.
Ke
y
s
es
s
io
n
b
et
w
ee
n
p
u
b
lis
h
er
/
b
r
o
k
er
Evaluation Warning : The document was created with Spire.PDF for Python.
I
n
t J
E
lec
&
C
o
m
p
E
n
g
I
SS
N:
2
0
8
8
-
8708
MQTT
-
P
R
E
S
E
N
T:
a
p
p
r
o
a
ch
t
o
s
ec
u
r
e
in
tern
et
o
f th
in
g
s
a
p
p
lica
tio
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s
u
s
in
g
MQTT
...
(
I
ma
n
e
S
a
h
mi)
4583
Fig
u
r
e
4
.
Ke
y
s
es
s
io
n
b
et
w
ee
n
b
r
o
k
er
/
s
u
b
s
cr
ib
er
Fig
u
r
e
5
.
E
n
cr
y
p
tio
n
/d
ec
r
y
p
ti
o
n
b
et
w
ee
n
p
u
b
lis
h
er
/
s
u
b
s
cr
ib
er
5.
SE
CUR
I
T
Y
DI
SCUS
SI
O
N
I
n
th
i
s
s
ec
tio
n
,
w
e
d
i
s
cu
s
s
t
h
e
s
ec
u
r
it
y
p
r
o
p
er
ties
th
at
ar
e
s
u
p
p
o
r
ted
b
y
o
u
r
s
o
l
u
tio
n
:
a.
A
u
t
h
en
t
icatio
n
:
E
v
er
y
t
h
i
n
g
o
n
th
e
I
n
ter
n
et
o
f
T
h
i
n
g
s
m
u
s
t
b
e
id
en
tif
iab
le
a
n
d
au
th
e
n
ticate
d
w
it
h
th
e
o
th
e
r
o
b
j
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ts
co
n
n
ec
ted
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s
o
it’s
a
ch
allen
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in
g
tas
k
b
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au
s
e
o
f
th
e
n
atu
r
e
o
f
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o
T
.
Ou
r
p
r
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p
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s
o
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tio
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r
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id
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ticatio
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th
e
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r
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d
th
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n
ts
(
p
u
b
lis
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s
an
d
s
u
b
s
cr
ib
er
s
)
[
2
4
]
.
1)
P
u
b
lis
h
er
(
s
u
b
s
cr
ib
er
)
au
th
e
n
t
icatio
n
:
t
h
e
p
u
b
lis
h
er
(
t
h
e
s
u
b
s
cr
ib
er
)
is
a
u
th
e
n
tica
ted
b
y
u
s
in
g
t
h
e
s
ess
io
n
k
e
y
Sk
p
(
S
k
s
)
ap
p
r
o
v
ed
b
y
th
e
u
s
a
g
e
o
f
t
h
e
A
u
g
P
A
KE
A
lg
o
r
i
th
m
.
2)
B
r
o
k
er
au
th
e
n
ticat
io
n
:
o
n
l
y
t
h
e
b
r
o
k
er
w
it
h
h
i
s
co
m
m
o
n
k
e
y
(
S
k
p
)
o
r
(
S
k
s
)
ca
n
d
ec
r
y
p
t
th
e
p
u
b
lis
h
a
n
d
s
u
b
s
cr
ib
e
m
e
s
s
a
g
es
f
r
o
m
p
u
b
l
is
h
er
s
a
n
d
s
u
b
s
cr
ib
er
s
w
h
o
u
s
e
th
e
co
m
m
o
n
b
r
o
k
er
k
e
y
s
.
b.
C
o
n
f
id
en
tia
lit
y
:
I
t
is
v
er
y
i
m
p
o
r
tan
t
to
en
s
u
r
e
t
h
at
t
h
e
d
at
a
is
s
ec
u
r
e
an
d
o
n
l
y
a
v
ailab
l
e
to
au
th
o
r
ized
u
s
er
s
.
An
o
t
h
er
p
o
in
t
th
a
t
t
h
e
u
s
er
s
o
f
I
o
T
m
u
s
t
b
e
a
w
ar
e
o
f
h
o
w
th
e
d
ata
i
s
m
an
a
g
ed
an
d
en
s
u
r
e
t
h
at
t
h
e
d
ata
is
p
r
o
tecte
d
th
r
o
u
g
h
th
e
p
r
o
ce
s
s
[
2
5
]
.
I
n
th
e
p
r
o
p
o
s
ed
s
o
lu
tio
n
th
e
p
u
b
lis
h
ed
m
e
s
s
a
g
e
is
p
r
o
tecte
d
t
w
ice,
f
ir
s
t
w
h
en
it
i
s
tr
an
s
f
er
r
ed
to
th
e
b
r
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k
er
,
b
y
u
s
i
n
g
th
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s
ec
u
r
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s
ess
io
n
g
e
n
er
ated
b
y
th
e
Au
g
P
A
K
E
A
l
g
o
r
ith
m
;
o
n
l
y
th
e
c
lien
t
w
h
o
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as
t
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e
s
e
s
s
io
n
k
e
y
ca
n
d
ec
r
y
p
t
th
e
m
e
s
s
a
g
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an
d
i
n
t
h
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s
ec
o
n
d
ti
m
e
i
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t
h
e
s
id
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o
f
th
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b
r
o
k
er
d
o
esn
’
t h
a
v
e
th
e
m
e
s
s
a
g
e
in
p
lai
n
te
x
t d
u
e
to
th
e
P
R
E
SENT
en
cr
y
p
tio
n
.
Evaluation Warning : The document was created with Spire.PDF for Python.
I
SS
N
:
2
0
8
8
-
8708
I
n
t J
E
lec
&
C
o
m
p
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n
g
,
Vo
l.
11
,
No
.
5
,
Octo
b
e
r
2
0
2
1
:
4
5
7
7
-
4586
4584
c.
I
n
teg
r
it
y
a
n
d
n
o
n
-
r
ep
u
d
iatio
n
:
I
t’
s
v
er
y
i
m
p
o
r
tan
t
to
en
s
u
r
e
th
e
ac
c
u
r
ac
y
o
f
t
h
e
d
ata;
th
a
t
it
is
cr
ea
ted
o
r
m
o
d
i
f
ied
b
y
t
h
e
au
t
h
o
r
ized
p
ar
t
y
o
n
l
y
.
T
h
e
in
teg
r
it
y
f
ea
tu
r
e
ca
n
b
e
i
m
p
o
s
ed
b
y
m
ai
n
tai
n
in
g
e
n
d
-
to
-
en
d
s
ec
u
r
it
y
in
I
o
T
c
o
m
m
u
n
ica
tio
n
.
T
h
is
is
w
h
at
o
u
r
s
o
lu
tio
n
p
r
o
v
id
er
s
,
th
e
en
d
-
to
-
en
d
s
ec
u
r
it
y
,
an
d
n
o
t
th
e
clien
t
to
en
d
s
ec
u
r
it
y
T
h
e
d
ata
is
en
c
r
y
p
ted
b
y
th
e
P
R
E
SEN
T
en
cr
y
p
tio
n
d
u
r
i
n
g
t
h
e
p
r
o
ce
s
s
o
f
p
u
b
lis
h
i
n
g
th
e
m
e
s
s
a
g
e,
th
e
b
r
o
k
er
h
a
s
n
o
id
ea
ab
o
u
t th
e
m
es
s
ag
e
tr
a
n
s
m
itted
[
2
4
]
.
Ou
r
co
n
tr
ib
u
tio
n
co
n
s
is
ts
o
f
r
ein
f
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g
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r
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t
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t
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r
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,
th
e
d
ata
is
s
to
r
e
d
b
y
th
e
b
r
o
k
er
in
an
en
cr
y
p
ted
f
o
r
m
a
t
(
P
R
E
SENT
en
cr
y
p
tio
n
)
.
T
h
e
p
r
o
p
o
s
e
d
s
y
s
te
m
p
r
o
v
id
es
t
h
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au
t
h
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n
t
icatio
n
o
f
p
u
b
lis
h
er
an
d
s
u
b
s
cr
ib
er
:
t
h
e
y
ar
e
a
u
th
en
ticated
w
i
th
t
h
e
b
r
o
k
er
b
y
u
s
i
n
g
t
h
e
s
es
s
io
n
k
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y
Sk
p
(
S
k
s
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ap
p
r
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v
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b
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e
u
s
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g
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o
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t
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u
g
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A
KE
alg
o
r
ith
m
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T
h
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co
n
f
id
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n
tialit
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in
t
eg
r
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y
,
a
n
d
n
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n
-
r
ep
u
d
iatio
n
o
f
MQ
T
T
m
ess
a
g
es
f
r
o
m
th
e
p
u
b
li
s
h
er
to
th
e
s
u
b
s
cr
ib
er
b
ec
au
s
e
th
e
b
r
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k
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o
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o
t
h
a
v
e
th
e
m
e
s
s
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g
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p
lain
te
x
t
d
u
e
to
th
e
P
R
E
SENT
en
cr
y
p
tio
n
.
B
y
u
s
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n
g
t
h
e
A
u
g
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A
KE
p
r
o
to
co
l
in
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u
r
ap
p
r
o
ac
h
,
an
attac
k
er
ca
n
g
et
(
C
p
,X
p
)
,
(
S,Y
p
)
,
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sp
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r
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cp
b
y
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p
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t
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n
n
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co
m
p
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te
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n
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th
e
n
ticated
s
e
s
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io
n
k
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y
(
S
k
p
)
s
h
ar
ed
b
et
w
ee
n
t
h
e
p
u
b
lis
h
er
an
d
th
e
b
r
o
k
er
,
th
er
e
f
o
r
e
it
’
s
s
ec
u
r
e
ag
ai
n
s
t
p
ass
iv
e
a
ttack
s
an
d
also
i
f
t
h
e
attac
k
er
co
n
tr
o
ls
th
e
e
x
c
h
an
g
e
m
es
s
ag
e,
h
e
ca
n
’
t
co
m
p
u
te
a
n
au
th
e
n
ticated
s
e
s
s
io
n
k
e
y
s
o
it’
s
s
ec
u
r
e
a
g
ai
n
s
t
ac
t
iv
e
at
tack
s
(
m
a
n
in
th
e
m
id
d
le
attac
k
/r
ep
la
y
attac
k
)
al
s
o
f
o
r
t
h
e
o
f
f
lin
e
/o
n
li
n
e
d
ictio
n
ar
y
a
ttack
s
[
2
6
]
.
Ou
r
co
n
tr
ib
u
tio
n
r
elate
d
to
t
h
e
p
r
ev
io
u
s
w
o
r
k
s
u
s
i
n
g
th
e
Au
g
P
A
KE
P
r
o
to
co
l
th
at
w
e
ad
d
th
e
P
R
E
SENT
en
cr
y
p
tio
n
th
at
p
r
o
v
id
es
m
o
r
e
p
r
o
tectio
n
to
th
e
b
r
o
k
er
,
th
e
m
ess
a
g
e
w
ill b
e
en
cr
y
p
ted
.
Ou
r
s
o
lu
tio
n
p
r
o
v
id
es:
a.
User
an
o
n
y
m
it
y
:
Fo
r
th
e
c
li
en
ts
(
s
u
b
s
cr
ib
er
/p
u
b
li
s
h
er
)
t
h
e
id
en
tit
y
o
f
th
e
clie
n
ts
is
p
r
o
tecte
d
u
s
in
g
Sk
s
/
Sk
p.
b.
M
ut
u
al
au
th
e
n
ticatio
n
:
By
u
s
in
g
t
h
e
s
e
s
s
io
n
c
h
a
n
n
e
l
Sk
s
(
Sk
p
)
b
et
w
ee
n
t
h
e
s
u
b
s
cr
i
b
er
/B
r
o
k
er
an
d
p
u
b
lis
h
er
/B
r
o
k
er
.
T
h
e
p
r
o
p
o
s
itio
n
v
al
id
ates
i
m
p
o
r
tan
t
p
o
in
ts
o
f
s
ec
u
r
it
y
f
o
r
I
o
T
u
s
in
g
t
h
e
MQ
T
T
p
r
o
to
co
l.
T
h
e
p
r
o
p
o
s
ed
s
o
lu
tio
n
is
s
ec
u
r
e
ag
ai
n
s
t:
c.
Ma
n
i
n
th
e
m
id
d
l
e
attac
k
:
T
h
e
attac
k
er
in
ter
f
er
e
b
et
w
ee
n
t
w
o
n
o
d
es
b
y
m
o
n
ito
r
in
g
,
ea
v
esd
r
o
p
p
in
g
,
an
d
co
n
tr
o
llin
g
th
e
co
m
m
u
n
icatio
n
b
et
w
ee
n
t
h
e
t
w
o
s
e
n
s
o
r
n
o
d
es to
ac
ce
s
s
th
e
r
es
tr
icted
d
ata
[
2
7
]
,
d.
T
h
e
r
ep
lay
attac
k
an
d
th
e
o
f
f
l
i
n
e
p
ass
w
o
r
d
g
u
e
s
s
i
n
g
attac
k
:
ev
en
i
f
th
e
attac
k
er
ca
n
g
u
es
s
a
p
ass
w
o
r
d
,
th
e
p
ar
am
eter
K
i
n
th
e
(
4
)
o
f
th
e
Au
g
P
A
KE
A
l
g
o
r
ith
m
i
s
d
er
iv
ed
in
d
ep
en
d
en
tl
y
f
r
o
m
t
h
e
g
u
e
s
s
ed
p
ass
w
o
r
d
.
W
e
m
a
k
e
th
i
s
T
ab
le
3
w
h
ich
s
u
m
m
ar
ize
s
o
m
e
ad
v
a
n
tag
e
s
o
f
o
u
r
p
r
o
p
o
s
ed
s
o
lu
tio
n
co
m
p
ar
ed
w
it
h
s
o
m
e
p
r
ev
io
u
s
w
o
r
k
s
,
s
o
m
e
o
f
t
h
ese
ad
v
a
n
ta
g
es:
User
a
n
o
n
y
m
i
t
y
,
m
u
t
u
al
au
t
h
e
n
ticatio
n
,
d
ata
co
n
f
id
e
n
tiali
t
y
d
ata
p
r
iv
ac
y
,
d
ata
i
n
teg
r
it
y
,
a
n
d
r
o
b
u
s
tn
e
s
s
a
g
ai
n
s
t
s
o
m
e
a
tta
ck
s
li
k
e
Ma
n
i
n
th
e
m
id
d
le,
th
e
o
f
f
li
n
e
p
as
s
w
o
r
d
g
u
e
s
s
i
n
g
attac
k
,
th
e
r
ep
la
y
a
ttack
.
T
h
e
r
esu
l
ts
s
ee
m
i
n
ter
esti
n
g
i
n
co
m
p
ar
is
o
n
w
it
h
t
h
e
o
th
er
s
o
l
u
tio
n
s
w
o
r
k
i
n
g
o
n
t
h
e
s
ec
u
r
it
y
o
f
MQ
T
T
.
T
h
e
s
ec
o
n
d
i
m
p
o
r
tan
t
p
ar
a
m
eter
to
tak
e
i
n
to
co
n
s
id
er
ati
o
n
is
t
h
e
es
ti
m
ated
co
s
t
ti
m
e
f
o
r
th
i
s
s
o
lu
t
io
n
,
ac
co
r
d
in
g
to
th
e
n
u
m
b
er
o
f
h
a
s
h
,
m
o
d
u
lar
ex
p
o
n
en
tiat
io
n
,
an
d
en
cr
y
p
t
i
o
n
o
p
er
atio
n
,
w
e
d
o
a
co
m
p
ar
is
o
n
o
f
th
e
e
s
ti
m
ated
co
s
t
ti
m
e
o
f
ea
c
h
s
o
l
u
tio
n
u
s
in
g
A
u
g
P
A
KE
(
Au
g
-
MQ
T
T
,
Au
t
h
-
MQ
T
T
,
Ou
r
A
p
p
r
o
ac
h
)
b
y
m
ak
in
g
th
e
s
e
p
ar
a
m
eter
s
,
th
e
r
es
u
lt
is
s
u
m
m
ar
ized
i
n
T
a
b
le
4
.
T
h
e
r
esu
lts
o
f
o
u
r
s
o
lu
tio
n
in
ter
m
s
o
f
t
h
e
p
ar
am
eter
s
cited
in
T
ab
le
4
,
lo
o
k
p
r
o
m
i
s
i
n
g
i
n
co
m
p
ar
is
o
n
w
it
h
th
e
o
th
er
s
o
lu
tio
n
s
,
w
e
ar
e
o
n
th
e
w
a
y
to
v
alid
ate
th
e
s
e
r
es
u
l
ts
b
y
s
i
m
u
latio
n
.
T
ab
le
3
.
So
m
e
ad
v
a
n
tag
e
s
o
f
t
h
e
p
r
o
p
o
s
ed
s
o
lu
tio
n
UA
MA
MIT
M
O
FP
a
t
t
a
c
k
Re
p
l
a
y
a
t
t
a
c
k
DC
DP
DI
A
[
6
]
[
1
1
]
[
9
]
[
1
7
]
[
1
4
]
[
1
5
]
O
u
r A
p
p
ro
a
c
h
N
o
t
e
:
U
A
:
U
s
e
r
A
n
o
n
y
mi
t
y
D
C
:
D
a
t
a
c
o
n
f
i
d
e
n
t
i
a
l
i
t
y
M
A
:
M
u
t
u
a
l
a
u
t
h
e
n
t
i
c
a
t
i
o
n
D
P
:
D
a
t
a
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S
[1
]
L
.
A
tzo
ri,
A
.
Ie
r
a
,
a
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d
G
.
M
o
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to
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T
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In
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s:
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su
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[2
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I.
Ya
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[3
]
F
.
A
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.
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F
.
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In
tern
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s
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[4
]
M
.
B.
Ya
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,
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Q.
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[5
]
J.
L
in
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.
Yu
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Y
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In
ter
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s
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/JIOT
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6
8
3
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0
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.
[6
]
R.
S
.
Ba
li
,
F
.
Ja
a
f
a
r,
a
n
d
P
.
Zav
a
ra
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,
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Pro
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3
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ter
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[7
]
A
.
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a
w
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a
,
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.
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ta,
a
n
d
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.
W
a
rd
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,
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r
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2
0
1
7
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1
th
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ter
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ms
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[8
]
A
.
Ra
h
m
a
n
,
S
.
Ro
y
,
M
.
S
.
Ka
ise
r,
a
n
d
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.
S
.
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m
,
“
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L
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g
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twe
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h
t
M
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lt
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-
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2
0
1
8
5
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In
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[9
]
A
.
Niru
n
tas
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k
ra
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p
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t,
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s,
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in
2
0
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6
IEE
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In
ter
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a
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Co
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re
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r
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c
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in
2
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1
7
In
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ti
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in
P
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n
d
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n
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d
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ti
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g
T
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h
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(
i
-
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0
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,
p
p
.
1
–
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,
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o
i:
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0
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1
1
0
9
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P
A
CT
.
2
0
1
7
.
8
2
4
5
1
2
6
.
[1
1
]
M
.
S
i
n
g
h
,
Ra
jan
M
.
A
.
,
S
h
iv
ra
j
V
.
L
.
,
a
n
d
Ba
lam
u
ra
li
d
h
a
r
P
.
,
“
S
e
c
u
re
M
QT
T
f
o
r
In
tern
e
t
o
f
T
h
in
g
s
(Io
T)
,
”
P
ré
se
n
té
à
2
0
1
5
Fi
ft
h
In
ter
n
a
ti
o
n
a
l
Co
n
fer
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n
c
e
o
n
Co
mm
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n
ica
ti
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n
S
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ste
ms
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n
d
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two
rk
T
e
c
h
n
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l
o
g
ies
,
2
0
1
5
,
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o
i:
1
0
.
1
1
0
9
/CS
NT
.
2
0
1
5
.
1
6
.
[1
2
]
A
.
M
e
k
to
u
b
i,
H.
L
.
Ha
ss
a
n
i,
H.
Be
lh
a
d
a
o
u
i
,
M
.
Rif
i,
a
n
d
A
.
Zak
a
ri,
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Ne
w
a
p
p
ro
a
c
h
f
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rin
g
c
o
m
m
u
n
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n
o
v
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r
M
QTT
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ro
to
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l
A
c
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m
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ra
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a
n
d
El
li
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ti
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C
u
rv
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in
2
0
1
6
T
h
ird
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ter
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ti
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l
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fer
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n
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e
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f
Co
ll
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0
1
6
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p
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1
–
6
,
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o
i:
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0
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1
1
0
9
/
S
Y
S
CO.2
0
1
6
.
7
8
3
1
3
2
6
.
[1
3
]
Y.
Up
a
d
h
y
a
y
,
A
.
Bo
ro
le,
a
n
d
D.
Dilee
p
a
n
,
“
M
QT
T
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a
se
d
se
c
u
re
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h
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e
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u
to
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m
,
”
in
2
0
1
6
S
y
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u
m
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l
Da
t
a
A
n
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lys
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n
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g
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0
1
6
,
p
p
.
1
–
4
,
d
o
i:
1
0
.
1
1
0
9
/CDA
N.2
0
1
6
.
7
5
7
0
9
4
5
.
[1
4
]
S
.
S
h
in
,
K.
K
o
b
a
ra
,
C.
C.
C
h
u
a
n
g
,
a
n
d
W
.
Hu
a
n
g
,
“
A
se
c
u
rit
y
f
ra
m
e
w
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rk
f
o
r
M
QTT
,
”
in
2
0
1
6
I
E
EE
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n
fer
e
n
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e
o
n
Co
mm
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n
ica
ti
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n
s
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n
d
Ne
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r
k
S
e
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u
rity
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)
,
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0
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6
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p
.
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3
2
–
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3
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,
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o
i:
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0
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1
1
0
9
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.
2
0
1
6
.
7
8
6
0
5
3
2
.
[1
5
]
M
.
Ca
lab
re
tt
a
,
R
.
P
e
c
o
ri,
M
.
V
e
c
c
h
io
,
a
n
d
L
.
V
e
lt
ri,
“
M
QT
T
-
A
u
th
:
a
T
o
k
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-
b
a
se
d
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lu
ti
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n
to
E
n
d
o
w
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Q
TT
w
it
h
A
u
th
e
n
ti
c
a
ti
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n
a
n
d
A
u
th
o
riza
ti
o
n
Ca
p
a
b
il
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ies
,
”
J
o
u
rn
a
l
o
f
Co
mm
u
n
ica
ti
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n
s
S
o
ft
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re
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n
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y
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.
1
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.
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p
.
3
2
0
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,
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ec.
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0
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2
4
1
3
8
/j
c
o
m
ss
.
v
1
4
i4
.
6
0
4
.
[1
6
]
S
.
H.
Ra
m
o
s,
M
.
T
.
V
il
lalb
a
,
a
n
d
R.
L
a
c
u
e
sta
,
“
M
Q
TT
S
e
c
u
rit
y
:
A
No
v
e
l
F
u
z
z
in
g
A
p
p
ro
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c
h
,
”
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ire
l.
Co
mm
u
n
.
M
o
b
.
Co
m
p
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t
,
v
o
l.
2
0
1
8
,
p
.
1
–
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,
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0
1
8
,
d
o
i:
1
0
.
1
1
5
5
/2
0
1
8
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2
6
1
7
4
6
.
[1
7
]
A
.
Es
fa
h
a
n
i
e
t
a
l.
,
“
A
L
i
g
h
twe
ig
h
t
A
u
th
e
n
ti
c
a
ti
o
n
M
e
c
h
a
n
is
m
f
o
r
M
2
M
Co
m
m
u
n
ica
ti
o
n
s
in
In
d
u
strial
Io
T
En
v
iro
n
m
e
n
t
,
”
IEE
E
I
n
ter
n
e
t
T
h
i
n
g
s J
.
,
v
o
l.
6
,
n
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1
,
p
p
.
2
8
8
–
2
9
6
,
F
e
b
.
2
0
1
9
,
d
o
i:
1
0
.
1
1
0
9
/JIOT
.
2
0
1
7
.
2
7
3
7
6
3
0
.
Evaluation Warning : The document was created with Spire.PDF for Python.
I
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N
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0
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Octo
b
e
r
2
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1
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4586
4586
[1
8
]
L
.
M
a
li
n
a
,
G
.
S
riv
a
sta
v
a
,
P
.
Dz
u
r
e
n
d
a
,
J.
Ha
j
n
y
,
a
n
d
R.
F
u
j
d
iak
,
“
A
S
e
c
u
re
P
u
b
li
sh
/
S
u
b
sc
rib
e
P
r
o
t
o
c
o
l
f
o
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n
tern
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t
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f
T
h
in
g
s,
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in
Pro
c
e
e
d
in
g
s
o
f
th
e
1
4
t
h
In
ter
n
a
ti
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n
a
l
C
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fer
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n
c
e
o
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Av
a
il
a
b
il
i
ty,
Relia
b
il
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ty
a
n
d
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e
c
u
rity
(
AR
ES
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9
)
,
Ca
n
terb
u
ry
,
C
A
,
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it
e
d
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m
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9
,
p
p
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–
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1
4
5
/
3
3
3
9
2
5
2
.
3
3
4
0
5
0
3
.
[1
9
]
N.
Na
ik
,
“
Ch
o
ice
o
f
e
ff
e
c
ti
v
e
m
e
ss
a
g
in
g
p
ro
to
c
o
ls
f
o
r
Io
T
s
y
st
e
m
s:
M
QTT
,
Co
A
P
,
A
M
QP
a
n
d
HTT
P
,
”
in
2
0
1
7
IEE
E
In
ter
n
a
ti
o
n
a
l
S
y
ste
ms
En
g
i
n
e
e
rin
g
S
y
mp
o
siu
m
(
IS
S
E
)
,
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n
n
a
,
A
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stria,
O
c
t.
2
0
1
7
,
p
p
.
1
–
7
,
d
o
i:
1
0
.
1
1
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9
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y
sEn
g
.
2
0
1
7
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8
0
8
8
2
5
1
.
[2
0
]
U.
Hu
n
k
e
ler,
H.
L
.
T
ru
o
n
g
,
a
n
d
A
.
S
tan
f
o
rd
-
Clark
,
“
M
QTT
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S
&
#
x
2
0
1
4
;
A
p
u
b
l
ish
/su
b
sc
rib
e
p
ro
t
o
c
o
l
f
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r
W
irele
s
s
S
e
n
so
r
Ne
tw
o
rk
s
,
”
in
2
0
0
8
3
rd
In
ter
n
a
t
io
n
a
l
C
o
n
fer
e
n
c
e
o
n
C
o
mm
u
n
ica
ti
o
n
S
y
ste
ms
S
o
ft
wa
re
a
n
d
M
id
d
lewa
re
a
n
d
W
o
rk
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o
p
s
(
COM
S
W
AR
E
’0
8
)
,
Ba
n
g
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,
In
d
ia,
J
a
n
.
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0
0
8
,
p
p
.
7
9
1
–
7
9
8
,
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o
i:
1
0
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1
1
0
9
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S
W
A
.
2
0
0
8
.
4
5
5
4
5
1
9
.
[2
1
]
A
.
Ba
n
k
s a
n
d
R
.
G
u
p
ta,
“
M
QT
T
V
e
rsio
n
3
.
1
.
1
,
”
Jt.
P
a
p
.
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p
e
n
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ro
u
p
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S
IS
OMG
,
2
0
1
4
.
[2
2
]
A
.
A
b
d
e
rra
h
im
,
F
.
Ib
ti
ss
a
m
,
C.
Ha
b
ib
a
,
E.
A
.
Hic
h
a
m
,
a
n
d
H.
Na
b
il
,
“
A
ES
-
P
re
se
n
t
:
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Ne
w
S
e
c
u
re
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T
-
Ba
se
d
S
c
h
e
m
e
f
o
r
T
e
l
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m
e
d
icin
e
a
nd
e
-
He
a
lt
h
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y
ste
m
s,
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PN
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o
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rn
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E
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n
d
Ap
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li
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e
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l.
1
3
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2
4
,
p
p
.
9
5
5
4
–
9
5
5
9
,
2
0
1
8
.
[2
3
]
A
.
Bo
g
d
a
n
o
v
e
t
a
l.
,
“
P
RE
S
ENT
:
A
n
u
lt
ra
-
li
g
h
tw
e
ig
h
t
b
lo
c
k
c
ip
h
e
r,
”
in
In
ter
n
a
ti
o
n
a
l
W
o
rk
sh
o
p
o
n
Cry
p
to
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r
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p
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ic
Ha
rd
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re
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n
d
Emb
e
d
d
e
d
S
y
ste
ms
,
2
0
0
7
,
p
p
.
4
5
0
–
4
6
6
,
d
o
i
:
1
0
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1
0
0
7
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7
8
-
3
-
5
4
0
-
7
4
7
3
5
-
2
_
3
1
.
[2
4
]
T
.
Yo
u
su
f
,
R.
M
a
h
m
o
u
d
,
F
.
A
lo
u
l
,
a
n
d
I.
Zu
a
lk
e
rn
a
n
,
“
In
ter
n
e
t
o
f
T
h
in
g
s
(Io
T
)
S
e
c
u
rit
y
:
Cu
rre
n
t
S
tatu
s,
Ch
a
ll
e
n
g
e
s
a
n
d
P
ro
s
p
e
c
ti
v
e
M
e
a
su
re
s,
”
In
ter
n
a
ti
o
n
a
l
J
o
u
rn
a
l
o
f
In
fo
rm
a
t
io
n
S
e
c
u
rity
Res
e
a
rc
h
(IJ
IS
R),
v
o
l.
5
,
n
o
.
4
,
p
p
.
6
0
8
–
6
1
6
,
De
c
.
2
0
1
5
.
[2
5
]
R.
Ro
m
a
n
,
J.
Z
h
o
u
,
a
n
d
J.
L
o
p
e
z
,
“
On
th
e
f
e
a
tu
re
s
a
n
d
c
h
a
ll
e
n
g
e
s
o
f
se
c
u
rit
y
a
n
d
p
r
iv
a
c
y
in
d
istri
b
u
ted
i
n
tern
e
t
o
f
th
in
g
s
,
”
Co
m
p
u
t
.
Ne
tw
,
v
o
l.
5
7
,
n
o
.
1
0
,
p
p
.
2
2
6
6
–
2
2
7
9
,
Ju
l
.
2
0
1
3
,
d
o
i:
1
0
.
1
0
1
6
/j
.
c
o
m
n
e
t.
2
0
1
2
.
1
2
.
0
1
8
.
[2
6
]
S
.
S
h
in
a
n
d
K.
Ko
b
a
ra
,
“
Eff
icie
n
t
a
u
g
m
e
n
ted
p
a
ss
w
o
rd
-
o
n
ly
a
u
t
h
e
n
ti
c
a
ti
o
n
a
n
d
k
e
y
e
x
c
h
a
n
g
e
f
o
r
IKEv
2
,
”
IET
F
RF
C
6
6
2
8
Exp
.
,
2
0
1
2
.
[2
7
]
I.
S
a
h
m
i,
T
.
M
a
z
ri,
a
n
d
N.
Hm
i
n
a
,
“
S
tu
d
y
o
f
th
e
Di
ff
e
re
n
t
S
e
c
u
rit
y
T
h
re
a
ts
o
n
th
e
In
tern
e
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in
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s
a
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d
th
e
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p
p
li
c
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d
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ter
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fo
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e
c
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rity
-
NIS
S
1
9
,
Ra
b
a
t,
M
o
r
o
c
c
o
,
2
0
1
9
,
p
p
.
1
–
6
,
d
o
i:
1
0
.
1
1
4
5
/
3
3
2
0
3
2
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3
3
2
0
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0
2
.
B
I
O
G
RAP
H
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S
O
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AUTH
O
RS
I
m
a
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a
h
m
i
,
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g
in
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in
tele
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m
m
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ste
m
s
f
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m
th
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a
l
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stit
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T
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m
m
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s
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b
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c
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,
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2
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1
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sh
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s
a
n
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in
f
r
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stru
c
tu
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th
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l
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c
h
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A
p
p
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d
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c
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k
e
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it
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sin
c
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s
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’s
c
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rre
n
tl
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a
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st
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t
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c
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o
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th
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tern
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o
f
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h
in
g
s sin
c
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2
0
1
6
w
it
h
t
h
e
S
y
ste
m
s
En
g
in
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l
a
b
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ra
t
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.
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r
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h
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m
Abd
e
ll
a
o
u
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ro
f
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ss
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r
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g
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Ed
u
c
a
ti
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n
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t
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a
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c
h
o
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p
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c
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c
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-
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n
it
ra
,
Ib
n
T
o
f
a
il
Un
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r
sit
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(
UIT
),
M
o
ro
c
c
o
.
M
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m
b
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r
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f
En
g
in
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rin
g
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c
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c
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s
L
a
b
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ra
to
ry
.
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c
u
rre
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t
re
se
a
rc
h
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tere
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d
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c
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rit
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tern
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a
n
d
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c
r
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p
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p
h
y
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m
a
d
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r
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r
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,
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r
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r
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c
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p
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o
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it
ra
a
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d
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P
e
rm
a
n
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n
t
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e
m
b
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r
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f
th
e
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e
c
t
rica
l
a
n
d
T
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le
c
o
m
m
u
n
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n
s
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g
in
e
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rin
g
L
a
b
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ra
to
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.
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R
d
e
g
re
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in
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t
w
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s
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n
d
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lec
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m
m
u
n
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o
n
f
ro
m
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n
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o
fa
il
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rsit
y
,
P
h
.
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d
e
g
re
e
in
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icro
e
lec
tro
n
ics
a
n
d
T
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lec
o
m
m
u
n
ica
ti
o
n
f
ro
m
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id
i
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o
h
a
m
e
d
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n
A
b
d
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ll
a
h
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i
v
e
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a
n
d
INP
T
o
f
Ra
b
a
t,
M
a
ste
r’s
d
e
g
re
e
in
M
icro
e
lec
tro
n
ics
a
n
d
T
e
le
c
o
m
m
u
n
ica
ti
o
n
S
y
ste
m
s,
Ba
c
h
e
lo
r’s d
e
g
re
e
in
tele
c
o
m
m
u
n
ica
ti
o
n
f
ro
m
Ca
d
i
Ay
y
a
d
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n
iv
e
rs
it
y
.
Na
b
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H
m
i
n
a
,
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r
o
f
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ss
o
r
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f
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h
e
r
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u
c
a
ti
o
n
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re
sid
e
n
t
o
f
S
u
lt
a
n
M
o
u
lay
S
li
m
a
n
e
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e
rsit
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sin
c
e
S
e
p
tem
b
e
r
2
0
1
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t
o
d
a
te,
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c
to
r
o
f
th
e
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ti
o
n
a
l
S
c
h
o
o
l
o
f
A
p
p
li
e
d
sc
ien
c
e
s 2
0
1
1
-
2
0
1
8
,
De
g
re
e
in
P
h
y
sic
s,
Op
ti
o
n
:
T
h
e
rm
o
d
y
n
a
m
ics
-
M
o
h
a
m
m
e
d
V
Un
iv
e
rsity
,
Un
iv
e
r
sit
y
Ph
.
D.
-
En
g
in
e
e
rin
g
S
c
ien
c
e
s,
Un
iv
e
r
sity
,
a
n
d
Eco
le
Ce
n
trale
d
e
Na
n
tes
,
1
9
9
4
,
HD
R
(1
st
i
n
M
o
ro
c
c
o
)
Ib
n
T
o
f
a
il
Un
iv
e
rsity
,
Ke
n
it
ra
,
2
0
0
2
.
V
ice
-
P
re
sid
e
n
t
f
o
r
A
c
a
d
e
m
ic
Aff
a
irs
a
n
d
In
f
o
rm
a
ti
o
n
T
e
c
h
n
o
lo
g
y
o
f
th
e
Un
iv
e
rsit
y
Ib
n
T
o
f
a
il
,
2
0
0
5
-
2
0
1
1
P
o
s
t
-
D
o
c
to
ra
l
Re
se
a
r
c
h
e
r:
EDF
-
t
h
e
rm
o
k
in
e
ti
c
s
L
a
b
o
ra
to
ry
o
f
Na
n
tes
,
1
9
9
4
-
1
9
9
5
,
Re
se
a
rc
h
En
g
in
e
e
r
a
t
P
o
ly
T
e
c
h
sc
h
o
o
l
o
f
Na
n
tes
,
1
9
9
5
-
1
9
9
7
.
Dire
c
t
o
r
o
f
th
e
re
se
a
rc
h
lab
o
ra
t
o
ry
"
S
y
ste
m
s
En
g
in
e
e
rin
g
"
sin
c
e
2
0
1
1
.
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