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r
ess
th
ese
g
ap
s
,
th
is
p
ap
er
p
r
o
p
o
s
es
a
m
u
lti
-
tier
ed
d
esig
n
f
r
am
ew
o
r
k
f
o
r
h
ig
h
e
r
ed
u
ca
tio
n
ce
r
tific
ates
u
s
in
g
d
esig
n
s
cie
n
ce
r
esear
ch
(
DSR
)
.
T
h
e
s
co
p
e
o
f
th
is
wo
r
k
f
o
cu
s
es
o
n
a
h
y
b
r
id
ar
c
h
itectu
r
e
co
m
b
in
in
g
o
f
f
-
ch
ain
in
ter
p
la
n
etar
y
f
ile
s
y
s
tem
(
I
PF
S
)
s
to
r
ag
e,
asy
m
m
etr
ic
en
c
r
y
p
tio
n
,
an
d
p
er
m
is
s
io
n
ed
on
-
ch
ain
SHA
-
2
5
6
h
ash
a
n
c
h
o
r
in
g
,
co
m
p
lem
en
ted
b
y
W
3
C
d
ec
en
tr
alize
d
i
d
en
tifie
r
s
(
DI
Ds)
f
o
r
i
d
en
tity
g
o
v
er
n
an
ce
.
Sp
ec
if
ically
,
th
e
o
b
jectiv
es
o
f
th
is
s
tu
d
y
ar
e
to
:
(
1
)
estab
lis
h
a
p
r
iv
ac
y
-
p
r
eser
v
in
g
cr
ed
e
n
tial
life
cy
cle
ar
ch
i
tectu
r
e;
(
2
)
m
iti
g
ate
u
n
au
th
o
r
ized
is
s
u
in
g
en
ti
ties
v
ia
a
s
m
ar
t
-
co
n
tr
ac
t
is
s
u
e
r
r
eg
is
tr
y
(
R
eg
_
I
)
;
(
3
)
f
o
r
m
alize
alg
o
r
ith
m
ic
p
r
o
ce
d
u
r
es
f
o
r
en
r
o
llm
en
t,
i
s
s
u
an
ce
,
an
d
en
cr
y
p
tio
n
;
a
n
d
(
4
)
e
m
p
ir
ically
b
en
ch
m
ar
k
s
y
s
tem
th
r
o
u
g
h
p
u
t
an
d
laten
cy
u
n
d
er
s
tr
ess
test
in
g.
T
h
e
m
ain
co
n
tr
ib
u
tio
n
s
o
f
th
is
r
esear
ch
ar
e
as f
o
llo
ws:
−
A
m
u
lti
-
tier
ed
d
esig
n
f
r
am
e
wo
r
k
(
DSR
Me
th
o
d
o
lo
g
y
)
:
Dev
elo
p
m
en
t
o
f
a
s
tr
u
ctu
r
e
d
,
f
o
u
r
-
la
y
er
ar
ch
itectu
r
e
(
A
p
p
licatio
n
a
n
d
u
s
er
in
te
r
f
ac
e,
i
d
en
tity
&
s
y
s
tem
m
an
ag
e
m
en
t,
tr
u
s
t
en
g
in
e,
a
n
d
v
er
if
ica
tio
n
)
u
s
in
g
th
e
DSR
m
eth
o
d
o
lo
g
y
s
p
ec
if
ically
tailo
r
e
d
f
o
r
h
ig
h
e
r
ed
u
ca
tio
n
cr
e
d
en
t
ials
.
−
Priv
ac
y
-
p
r
eser
v
i
n
g
h
y
b
r
i
d
ar
ch
itectu
r
e
:
I
n
teg
r
atio
n
o
f
o
f
f
-
ch
ain
d
ec
en
tr
alize
d
s
to
r
a
g
e
(
I
PF
S)
with
asy
m
m
etr
ic
en
cr
y
p
tio
n
(
en
cr
y
p
tin
g
ce
r
tific
ate
ar
tifa
cts
u
s
in
g
th
e
s
tu
d
e
n
t'
s
p
u
b
lic
k
ey
)
p
air
ed
with
on
-
ch
ain
cr
y
p
to
g
r
a
p
h
ic
h
ash
a
n
ch
o
r
in
g
(
SHA
-
2
5
6
)
to
e
n
s
u
r
e
d
ata
s
o
v
er
eig
n
ty
,
an
d
s
ca
lab
ilit
y
.
−
Self
-
s
o
v
er
eig
n
id
en
tity
a
n
d
a
n
ti
-
r
o
g
u
e
is
s
u
er
m
ec
h
an
is
m
:
Utilizatio
n
o
f
W
3
C
DI
D
s
f
o
r
is
s
u
er
s
an
d
h
o
ld
er
s
,
co
m
b
in
ed
with
a
s
m
a
r
t
-
co
n
tr
ac
t
-
b
ac
k
ed
I
s
s
u
er
R
eg
is
tr
y
(
R
eg
_
I
)
a
n
d
Glo
b
al
R
ev
o
ca
tio
n
L
is
t
to
r
estrict
u
n
au
th
o
r
ized
is
s
u
in
g
e
n
titi
es a
n
d
h
an
d
le
c
r
ed
en
tial in
v
alid
atio
n
.
−
Fo
r
m
al
alg
o
r
ith
m
ic
p
r
o
t
o
co
ls
:
Def
in
itio
n
o
f
s
tep
-
by
-
s
tep
alg
o
r
ith
m
s
,
s
p
ec
if
ically
ad
m
i
n
/u
s
er
en
r
o
llm
e
n
t
(
Alg
o
r
ith
m
1
)
,
ce
r
tific
ate
is
s
u
an
ce
(
Alg
o
r
ith
m
2
)
,
a
n
d
ce
r
tific
ate
en
cr
y
p
tio
n
a
n
d
o
f
f
-
ch
ain
s
to
r
ag
e
(
Alg
o
r
ith
m
3
)
.
−
E
m
p
ir
ical
b
en
c
h
m
ar
k
in
g
a
n
d
ev
alu
atio
n
:
C
o
m
p
r
eh
en
s
iv
e
p
e
r
f
o
r
m
a
n
ce
ev
al
u
atio
n
o
f
th
e
p
r
o
to
ty
p
e
u
s
in
g
Hy
p
er
led
g
e
r
C
alip
er
ac
r
o
s
s
I
s
s
u
e
,
V
erif
y
,
an
d
Mixed
wo
r
k
lo
ad
s
,
d
em
o
n
s
tr
atin
g
a
1
0
0
%
tr
an
s
ac
tio
n
s
u
cc
ess
r
ate,
a
s
tab
le
th
r
o
u
g
h
p
u
t
o
f
~1
7
.
7
T
PS
,
an
d
v
er
if
icatio
n
laten
cies
as
lo
w
as
1
0
.
5
3
m
s
.
T
o
h
i
g
h
lig
h
t
th
e
m
ain
d
if
f
e
r
e
n
ce
s
an
d
ad
v
an
tag
es
o
f
th
e
p
r
o
p
o
s
ed
s
ch
em
e,
T
ab
le
1
p
r
o
v
i
d
es
a
d
etailed
co
m
p
ar
is
o
n
b
etwe
en
o
u
r
ap
p
r
o
ac
h
a
n
d
ex
is
tin
g
p
r
im
ar
y
c
r
ed
en
tial
r
e
v
o
ca
tio
n
m
o
d
els
u
s
ed
in
d
ig
ital
id
en
tity
an
d
b
lo
ck
c
h
ain
s
y
s
tem
s
.
T
ab
le
1
.
C
o
m
p
a
r
is
o
n
o
f
th
e
p
r
o
p
o
s
ed
wo
r
k
with
s
o
m
e
p
r
im
a
r
y
cr
ed
e
n
tial r
ev
o
ca
tio
n
m
o
d
el
s
u
s
ed
in
d
ig
ital id
en
tity
an
d
b
lo
c
k
ch
ain
s
y
s
tem
s
F
e
a
t
u
r
e
/
d
i
me
n
si
o
n
C
e
n
t
r
a
l
i
z
e
d
/
P
K
I
sy
st
e
ms
N
a
i
v
e
on
-
c
h
a
i
n
sy
st
e
ms
S
t
a
n
d
a
r
d
d
e
c
e
n
t
r
a
l
i
z
e
d
mo
d
e
l
s
O
u
r
p
r
o
p
o
s
e
d
f
r
a
mew
o
r
k
D
a
t
a
P
r
i
v
a
c
y
(
G
D
P
R
/
F
ER
P
A
)
Lo
w
(
C
e
n
t
r
a
l
i
z
e
d
st
o
r
a
g
e
)
N
o
n
-
c
o
m
p
l
i
a
n
t
(
P
I
I
on
-
c
h
a
i
n
)
P
a
r
t
i
a
l
(
U
n
e
n
c
r
y
p
t
e
d
o
f
f
-
c
h
a
i
n
)
H
i
g
h
(
A
sy
m
me
t
r
i
c
En
c
r
y
p
t
i
o
n
+
Off
-
C
h
a
i
n
I
P
F
S
)
I
d
e
n
t
i
t
y
G
o
v
e
r
n
a
n
c
e
S
i
n
g
l
e
C
A
d
e
p
e
n
d
e
n
c
y
N
o
n
e
/
W
e
a
k
B
a
si
c
W
a
l
l
e
t
A
d
d
r
e
ss
e
s
W
3
C
D
I
D
s +
S
mart
-
C
o
n
t
r
a
c
t
R
e
g
i
s
t
r
y
(
R
e
g
_
I
)
R
e
v
o
c
a
t
i
o
n
C
a
p
a
b
i
l
i
t
y
M
a
n
u
a
l
/
D
B
U
p
d
a
t
e
H
a
r
d
t
o
i
m
p
l
e
me
n
t
P
a
r
t
i
a
l
On
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c
h
a
i
n
G
l
o
b
a
l
R
e
v
o
c
a
t
i
o
n
L
i
st
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i
n
g
l
e
P
o
i
n
t
o
f
F
a
i
l
u
r
e
H
i
g
h
R
i
s
k
Lo
w
R
i
s
k
Lo
w
R
i
s
k
Ze
r
o
R
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sk
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D
e
c
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n
t
r
a
l
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d
A
r
c
h
i
t
e
c
t
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r
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)
F
o
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mal
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a
t
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M
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s
N
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Th
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i
c
a
l
o
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a
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c
t
h
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o
u
g
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t
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l
g
o
r
i
t
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m
i
c
P
r
o
t
o
c
o
l
s +
C
a
l
i
p
e
r
W
o
r
k
l
o
a
d
S
t
r
e
ss
Te
st
i
n
g
T
h
e
b
lo
ck
ch
ai
n
'
s
[
9
]
h
is
to
r
y
h
as
b
eg
u
n
s
in
ce
2
0
0
8
,
wh
e
n
Sato
s
h
i
Nak
am
o
to
[
4
]
d
es
ig
n
ed
th
e
b
lo
ck
ch
ain
as
th
e
b
u
ild
in
g
b
lo
ck
f
o
r
B
itco
in
.
Sin
ce
th
e
n
,
b
lo
ck
ch
ai
n
h
as
b
e
co
m
e
a
s
ig
n
if
ican
t
p
a
r
t
o
f
p
r
o
v
id
i
n
g
in
f
o
r
m
atio
n
s
ec
u
r
ity
in
ed
u
ca
tio
n
,
h
ea
lth
ca
r
e,
f
in
a
n
cial
tech
n
o
lo
g
y
,
a
n
d
ev
e
n
g
a
m
in
g
[
3
]
,
[
1
0
]
.
B
lo
ck
ch
ain
is
a
ter
m
u
s
ed
to
r
ef
er
to
a
v
ar
iety
o
f
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r
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to
co
ls
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d
tech
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o
lo
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th
at
m
a
k
e
it
p
o
s
s
ib
le
to
r
ec
o
r
d
i
n
f
o
r
m
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n
in
a
way
t
h
at
is
d
if
f
icu
lt
to
alter
,
h
ac
k
,
o
r
f
o
r
g
e
[
1
1
]
.
B
lo
ck
ch
ain
is
a
f
o
r
m
o
f
d
is
tr
ib
u
ted
led
g
er
tech
n
o
lo
g
y
;
th
is
m
ea
n
s
th
e
h
is
to
r
y
o
f
th
a
t
led
g
er
(
th
e
'
tr
u
th
'
)
an
d
th
e
d
ata
co
n
tr
o
lled
th
er
eo
n
is
k
ep
t
ac
r
o
s
s
m
u
ltip
le
in
d
ep
en
d
en
t
en
titi
es
(
b
lo
ck
s
)
,
h
o
s
ted
o
n
a
co
m
m
o
n
b
asis
b
y
a
n
et
wo
r
k
o
f
co
m
p
u
ter
s
(
th
e
ch
ain
)
[
3
]
,
[
1
1
]
,
[
1
2
]
.
C
h
an
g
es
to
th
e
led
g
er
ca
n
b
e
s
ee
n
b
y
ev
e
r
y
o
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with
in
th
e
n
etwo
r
k
,
wh
ich
is
m
ain
tain
ed
as
a
wh
o
le.
T
h
ese
k
ey
f
ea
tu
r
es
m
ak
e
it
v
e
r
y
s
u
i
tab
le
f
o
r
m
a
n
ag
in
g
th
e
'
life
cy
cle'
o
f
a
ce
r
tific
ate,
Evaluation Warning : The document was created with Spire.PDF for Python.
I
SS
N:
2
2
5
2
-
8
7
7
6
I
n
t J I
n
f
&
C
o
m
m
u
n
T
ec
h
n
o
l
,
Vo
l.
15
,
No
.
4
,
Dec
em
b
er
20
26
:
1
8
0
0
-
1
8
1
5
1802
f
r
o
m
o
r
i
g
in
atio
n
th
r
o
u
g
h
am
e
n
d
m
en
t
to
v
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i
f
icatio
n
b
y
a
th
ir
d
p
ar
ty
,
lik
e
an
em
p
lo
y
er
.
E
d
u
ca
tio
n
al
s
y
s
tem
s
cu
r
r
en
tly
u
s
in
g
b
lo
c
k
ch
ain
.
Sev
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u
ca
tio
n
al
in
s
titu
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d
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k
ch
ain
tech
n
o
lo
g
y
to
is
s
u
e
an
d
m
an
a
g
e
d
ig
ital
cr
ed
en
tials
.
Her
e
ar
e
s
o
m
e
n
o
ta
b
le
ex
am
p
les
,
a)
B
lo
ck
ce
r
t:
[
1
3
]
is
o
p
en
‐
s
o
u
r
ce
b
lo
ck
c
h
ain
p
r
o
ject
f
o
r
cr
ea
tin
g
,
is
s
u
in
g
,
v
iewin
g
,
an
d
v
er
i
f
y
in
g
b
lo
ck
ch
ain
-
b
ased
ce
r
tific
ates.
Dev
elo
p
ed
b
y
th
e
Ma
s
s
ac
h
u
s
etts
I
n
s
titu
te
o
f
T
ec
h
n
o
lo
g
y
ai
m
s
to
p
r
o
v
id
e
a
s
ec
u
r
e
an
d
tam
p
er
-
p
r
o
o
f
way
to
is
s
u
e
an
d
v
e
r
if
y
c
er
tific
ates,
s
u
ch
as
ac
a
d
em
i
c
cr
ed
e
n
tials
,
p
r
o
f
ess
io
n
al
ce
r
tific
atio
n
s
,
an
d
o
th
e
r
v
e
r
i
f
iab
le
c
r
ed
en
tials
.
I
t
en
ab
les
s
tu
d
e
n
ts
an
d
em
p
lo
y
er
s
to
b
e
a
b
le
to
ac
ce
s
s
th
e
B
lo
ck
ce
r
ts
p
la
tf
o
r
m
b
y
th
e
B
lo
ck
ce
r
ts
m
o
b
ile
ap
p
licatio
n
f
o
r
v
er
if
icati
o
n
p
u
r
p
o
s
es.
T
h
e
p
latf
o
r
m
u
s
es th
e
b
itco
in
b
lo
ck
ch
ain
as a
p
r
o
v
id
er
o
f
tr
u
s
t,
an
d
h
en
ce
t
h
e
d
ata
is
im
m
u
t
ab
le
[
1
4
]
.
b)
Un
iv
er
s
ity
o
f
Nico
s
ia:
h
as
e
m
b
r
ac
ed
th
is
tech
n
o
lo
g
y
to
r
eim
ag
in
e
h
o
w
ac
a
d
em
ic
ac
h
iev
em
en
ts
ar
e
r
ec
o
r
d
e
d
,
s
h
ar
e
d
,
a
n
d
v
er
if
ie
d
.
I
t
was
o
n
e
o
f
th
e
f
ir
s
t
u
n
iv
e
r
s
ities
to
is
s
u
e
b
lo
ck
ch
ain
-
b
ased
ce
r
tific
ates.
R
ec
o
r
d
in
g
t
h
ese
ce
r
tific
ates
o
n
th
e
b
l
o
ck
ch
ain
in
v
o
lv
es
cr
y
p
to
g
r
ap
h
ic
s
ig
n
in
g
an
d
h
ash
in
g
,
wh
ic
h
allo
ws
f
o
r
in
s
tan
t
v
e
r
if
icatio
n
o
f
th
eir
v
alid
ity
with
o
u
t
t
h
e
n
ee
d
to
co
n
tact
o
r
in
v
o
lv
e
th
e
is
s
u
in
g
in
s
titu
tio
n
d
u
r
in
g
th
e
v
e
r
if
icatio
n
p
r
o
ce
s
s
[
1
5
]
.
c)
Op
en
C
er
ts
:
[
1
6
]
is
an
o
p
e
n
s
tan
d
ar
d
f
o
r
is
s
u
in
g
an
d
v
e
r
if
y
in
g
ed
u
ca
tio
n
cr
e
d
en
tials
th
r
o
u
g
h
th
e
E
th
er
eu
m
b
lo
ck
c
h
ain
,
p
r
im
ar
ily
d
ev
elo
p
ed
i
n
Si
n
g
a
p
o
r
e
an
d
co
lla
b
o
r
atio
n
am
o
n
g
f
o
u
r
g
o
v
er
n
m
e
n
t
tech
n
o
lo
g
y
ag
en
cies.
I
t
allo
ws
ed
u
ca
tio
n
al
in
s
titu
tio
n
s
to
is
s
u
e
tam
p
er
-
p
r
o
o
f
d
ig
ital
ce
r
ti
f
icate
s
,
wh
ich
ca
n
b
e
ea
s
ily
v
e
r
if
ied
b
y
em
p
l
o
y
er
s
an
d
o
th
er
s
tak
eh
o
ld
e
r
s
with
o
u
t
r
ely
i
n
g
o
n
th
e
i
n
s
titu
tio
n
th
at
is
s
u
ed
th
e
ce
r
tific
ate
in
s
tead
o
f
s
u
b
m
itti
n
g
th
e
p
h
y
s
ical
co
p
y
.
d)
T
r
u
s
tED
:
[
1
7
]
is
a
b
lo
ck
c
h
ai
n
-
b
ased
p
latf
o
r
m
t
h
at
was
d
e
v
elo
p
ed
b
y
K
o
s
ta
B
atza
v
alis
in
Au
s
tr
alia
in
2
0
1
7
.
I
t a
im
s
to
ad
d
r
ess
is
s
u
es
o
f
cr
ed
en
tial f
r
a
u
d
an
d
s
tr
ea
m
lin
e
th
e
v
er
if
icatio
n
p
r
o
ce
s
s
f
o
r
ed
u
ca
tio
n
al
q
u
alif
icatio
n
s
b
y
lev
er
ag
in
g
t
h
e
tr
an
s
p
ar
en
c
y
an
d
im
m
u
tab
i
lity
o
f
b
lo
ck
c
h
ain
tech
n
o
lo
g
y
.
T
h
e
p
latf
o
r
m
allo
ws
f
o
r
in
s
tan
t
v
er
if
icatio
n
o
f
cr
ed
en
tials
,
r
ed
u
cin
g
th
e
tim
e
an
d
ef
f
o
r
t
r
eq
u
ir
e
d
b
y
em
p
lo
y
er
s
,
in
s
titu
tio
n
s
,
an
d
o
th
er
s
tak
eh
o
ld
er
s
.
Stu
d
en
ts
h
av
e
co
n
tr
o
l
o
v
er
th
eir
d
ata
an
d
ca
n
ch
o
o
s
e
wh
o
to
s
h
ar
e
th
eir
cr
ed
en
tials
with
,
en
h
an
ci
n
g
p
r
i
v
ac
y
an
d
s
ec
u
r
ity
.
2.
RE
L
AT
E
D
WO
RK
S
T
h
is
s
ec
tio
n
f
o
cu
s
es
o
n
r
elate
d
r
esear
ch
wo
r
k
s
id
en
tifi
ed
d
u
r
in
g
th
e
d
etailed
li
ter
atu
r
e
s
u
r
v
ey
f
o
r
im
p
r
o
v
in
g
p
u
b
lic
b
lo
ck
c
h
ai
n
s
f
o
r
ac
ad
em
ic
ce
r
tific
ate
ce
r
tific
atio
n
.
R
esear
ch
o
n
th
e
a
p
p
licatio
n
o
f
b
lo
ck
ch
ain
tech
n
o
lo
g
y
in
h
ig
h
er
ed
u
ca
tio
n
h
as
b
ee
n
g
ain
i
n
g
s
ig
n
if
ican
t
in
ter
est,
f
o
cu
s
in
g
o
n
ar
ea
s
s
u
ch
as
s
m
ar
t
co
n
tr
ac
ts
,
p
r
i
v
ac
y
,
ac
c
r
ed
itatio
n
p
r
o
ce
s
s
es,
an
d
k
n
o
w
led
g
e
m
an
a
g
em
en
t.
R
aim
u
n
d
o
an
d
R
o
s
ár
io
[
1
8
]
p
r
esen
ted
a
s
y
s
tem
atic
r
e
v
iew
o
f
3
7
ar
ticles
o
n
th
e
u
s
e
o
f
b
lo
ck
ch
ai
n
tech
n
o
lo
g
y
i
n
h
ig
h
er
ed
u
ca
tio
n
.
I
t
h
ig
h
lig
h
ts
h
o
w
b
lo
c
k
ch
ain
is
en
h
an
ci
n
g
e
f
f
icien
cy
,
ef
f
ec
tiv
en
ess
,
p
r
iv
ac
y
co
n
t
r
o
l,
a
n
d
s
ec
u
r
ity
o
f
d
at
a
m
an
ag
em
en
t
m
ec
h
a
n
is
m
s
in
h
ig
h
er
ed
u
ca
tio
n
p
r
o
ce
s
s
es.
T
h
e
p
o
ten
tial
b
en
ef
its
o
f
b
lo
ck
ch
ain
tech
n
o
lo
g
y
in
h
ig
h
er
e
d
u
ca
tio
n
ar
e
d
is
cu
s
s
ed
,
alo
n
g
with
f
u
tu
r
e
r
esear
ch
d
ir
ec
tio
n
s
.
T
h
e
r
ef
er
e
n
ce
s
o
f
th
e
ar
ticle
co
v
e
r
v
ar
io
u
s
ap
p
licatio
n
s
o
f
b
l
o
ck
ch
ain
in
h
i
g
h
er
e
d
u
ca
tio
n
,
s
u
ch
as
d
ip
lo
m
a
a
n
ti
-
f
o
r
g
er
y
s
y
s
tem
s
,
o
n
lin
e
q
u
iz
s
ch
em
es,
an
d
ac
h
iev
em
e
n
t
r
e
co
r
d
s
y
s
tem
s
.
B
ab
u
et
a
l
.
[
1
9
]
d
is
cu
s
s
ed
th
e
lim
itatio
n
s
o
f
p
u
b
lic
b
lo
c
k
ch
ain
s
f
o
r
ac
ad
em
ic
ce
r
tific
ate
ce
r
tifi
ca
tio
n
,
s
u
ch
as
p
r
iv
ac
y
co
n
ce
r
n
s
an
d
s
ca
lab
ilit
y
is
s
u
es,
an
d
p
r
o
p
o
s
e
a
s
o
lu
tio
n
u
s
in
g
a
p
er
m
is
s
io
n
ed
b
l
o
ck
c
h
ain
n
etwo
r
k
,
s
p
ec
if
ically
Hy
p
er
led
g
e
r
Fab
r
ic,
f
o
r
th
e
s
e
cu
r
e
is
s
u
an
ce
an
d
v
er
if
icatio
n
o
f
d
i
g
ital
ac
ad
em
ic
ce
r
tific
ates.
T
h
is
s
y
s
tem
en
h
an
ce
s
tr
an
s
p
ar
en
cy
,
s
ec
u
r
ity
,
an
d
r
eliab
ilit
y
b
y
elim
in
atin
g
th
e
n
ee
d
f
o
r
in
te
r
m
ed
iar
ies
an
d
e
n
s
u
r
in
g
tam
p
er
-
p
r
o
o
f
r
ec
o
r
d
s
th
r
o
u
g
h
a
s
tr
u
ctu
r
ed
p
r
o
ce
s
s
in
v
o
lv
in
g
cr
y
p
to
g
r
ap
h
ic
s
tep
s
.
T
h
e
p
ap
er
o
u
tlin
es
th
e
ar
c
h
itectu
r
e
an
d
p
r
o
ce
s
s
es
f
o
r
m
an
ag
in
g
ac
ad
em
i
c
ce
r
tific
ates,
in
clu
d
in
g
is
s
u
an
c
e
an
d
v
er
i
f
icatio
n
p
h
ases
,
an
d
s
u
g
g
ests
f
u
tu
r
e
im
p
r
o
v
em
e
n
ts
f
o
r
b
etter
id
en
tity
m
an
ag
em
en
t
an
d
co
n
s
en
s
u
s
m
ec
h
an
is
m
s
.
Al
Hem
air
y
et
a
l
.
[
2
0
]
d
is
cu
s
s
ed
th
e
ap
p
licatio
n
o
f
b
lo
ck
c
h
ain
tech
n
o
lo
g
y
in
ed
u
ca
tio
n
,
p
ar
t
icu
lar
ly
f
o
r
th
e
d
e
v
elo
p
m
en
t
an
d
v
er
if
icatio
n
o
f
d
ig
ital
ac
ad
em
ic
cr
ed
en
tials
.
I
t
h
ig
h
lig
h
ted
v
a
r
io
u
s
p
r
o
jects
an
d
in
itiativ
es,
s
u
ch
as
C
er
b
er
u
s
,
B
lo
ck
ce
r
ts
,
Op
en
C
er
ts
,
a
n
d
E
d
u
C
T
X,
wh
ich
u
tili
ze
b
lo
ck
ch
ain
f
o
r
s
ec
u
r
e
c
r
ed
en
tial
m
an
ag
e
m
en
t.
T
h
e
p
r
o
p
o
s
ed
f
r
am
ewo
r
k
s
aim
t
o
en
h
an
ce
s
ec
u
r
ity
a
n
d
p
r
iv
ac
y
to
is
s
u
e
an
d
v
er
if
y
d
ig
ital
ac
ad
em
ic
cr
ed
en
tials
u
s
in
g
th
e
E
C
DS
A
alg
o
r
ith
m
.
T
h
e
r
esear
ch
em
p
h
asizes
th
e
p
o
te
n
tial
o
f
b
lo
ck
ch
ain
to
im
p
r
o
v
e
th
e
in
teg
r
ity
an
d
ef
f
icien
c
y
o
f
ac
a
d
em
ic
cr
ed
e
n
tialin
g
p
r
o
ce
s
s
es,
s
u
p
p
o
r
ted
b
y
v
ar
io
u
s
s
tu
d
ies
an
d
g
lo
b
al
ad
o
p
tio
n
ex
am
p
les.
Gh
o
r
ab
et
a
l
.
[
2
1
]
in
tr
o
d
u
ce
s
PalC
er
t,
a
b
lo
ck
ch
ain
-
b
ased
s
y
s
tem
d
esig
n
ed
to
v
er
if
y
an
d
attest
a
ca
d
em
ic
ce
r
tific
ates
in
Palest
in
e,
wh
ich
aim
s
to
im
p
r
o
v
e
th
e
cu
r
r
en
t
m
an
u
al
p
r
o
ce
s
s
es
o
v
er
s
ee
n
b
y
th
e
Min
is
tr
y
o
f
Hig
h
e
r
E
d
u
ca
tio
n
(
M
OHE
)
.
So
lid
ity
was
u
s
ed
to
wr
ite
s
m
ar
t
co
n
tr
ac
ts
,
wh
ile
th
e
p
r
o
p
o
s
ed
f
r
am
ew
o
r
k
was
ev
alu
ated
u
s
in
g
th
e
E
th
er
eu
m
R
o
p
s
ten
n
etwo
r
k
.
T
h
e
p
r
o
ject
aim
s
to
c
r
ea
te
an
ec
o
s
y
s
tem
b
ased
o
n
a
n
o
p
en
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[
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IPFS
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Th
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)
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3.
M
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T
H
O
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Desig
n
in
g
a
b
lo
ck
ch
ain
-
b
ased
f
r
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ewo
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k
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h
ig
h
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ed
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c
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ce
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tific
ates
in
v
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lv
es
a
s
y
s
tem
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ap
p
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o
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h
,
en
co
m
p
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in
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ev
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d
is
tin
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p
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:
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clu
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in
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th
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ty
p
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f
r
am
ewo
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k
ar
ch
itectu
r
e,
th
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f
u
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ctio
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in
g
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f
th
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d
etec
tio
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ith
m
,
th
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im
p
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tatio
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p
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s
s
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d
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h
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s
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ed
to
ass
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’
s
p
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f
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.
T
h
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p
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s
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lo
g
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DSR
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p
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,
f
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cu
s
in
g
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ev
elo
p
m
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t o
f
a
m
u
lti
-
tier
b
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c
h
ain
ar
c
h
itectu
r
e.
3
.
1
.
Requirem
ent
a
na
ly
s
is
a
nd
des
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n
s
t
a
k
eho
lder
identi
f
ica
t
io
n
3
.
1
.
1
.
I
dentif
y
t
he
pla
y
er
s
(
a
ct
o
rs)
A
cr
itical
f
ir
s
t
s
tep
is
to
id
e
n
tify
th
e
k
ey
p
ar
ticip
a
n
ts
,
o
r
ac
t
o
r
s
,
with
in
th
is
b
lo
ck
ch
ai
n
-
b
a
s
ed
s
y
s
tem
f
o
r
ce
r
tific
ate
is
s
u
an
ce
an
d
m
an
ag
em
en
t.
T
h
ese
ac
to
r
s
m
ay
o
r
ig
in
ate
f
r
o
m
with
in
th
e
c
o
n
f
in
es
o
f
th
e
s
y
s
tem
o
r
m
ay
e
x
is
t e
x
ter
n
ally
,
e
n
g
ag
in
g
in
v
a
r
io
u
s
in
ter
ac
tio
n
s
eith
er
with
th
e
s
y
s
tem
its
elf
o
r
with
ea
ch
o
t
h
er
.
I
n
th
e
co
n
tex
t o
f
o
u
r
b
lo
c
k
ch
a
in
f
r
am
ewo
r
k
f
o
r
ce
r
tific
ates,
t
h
e
id
en
tifie
d
ac
t
o
r
s
in
clu
d
e
,
−
Ass
u
r
e
(
C
o
lleg
es/u
n
iv
er
s
ity
)
will is
s
u
e
ce
r
tific
ates.
−
Ho
ld
er
(
Stu
d
en
ts
)
will r
ec
eiv
e
th
em
.
−
Ver
if
ier
(
E
m
p
lo
y
er
)
will c
h
ec
k
th
eir
v
alid
ity
.
Evaluation Warning : The document was created with Spire.PDF for Python.
I
SS
N:
2
2
5
2
-
8
7
7
6
I
n
t J I
n
f
&
C
o
m
m
u
n
T
ec
h
n
o
l
,
Vo
l.
15
,
No
.
4
,
Dec
em
b
er
20
26
:
1
8
0
0
-
1
8
1
5
1804
3
.
1
.
2
.
I
dentif
y
t
he
f
un
ct
io
na
l a
nd
ro
les
I
n
th
is
s
tep
,
th
e
g
o
al
is
to
d
ef
i
n
in
g
t
h
e
f
u
n
ctio
n
al
an
d
n
o
n
f
u
n
ctio
n
al
r
e
q
u
ir
em
e
n
ts
an
d
o
p
e
r
atio
n
s
f
o
r
th
e
s
y
s
tem
as th
e
f
o
llo
win
g
.
T
ab
le
3
s
u
m
m
ar
izes th
e
r
e
q
u
ir
e
m
en
ts
g
ath
er
ed
f
r
o
m
i
n
ter
v
ie
ws with
Aca
d
em
y
o
f
Gr
ad
u
ate
Stu
d
ies
an
d
L
ib
y
a
n
u
n
iv
er
s
ities
wh
ich
in
clu
d
es
th
e
s
ec
tio
n
s
:
T
h
e
Stu
d
en
t
Ad
m
in
is
tr
atio
n
Of
f
ice,
r
esp
o
n
s
ib
le
f
o
r
v
er
if
icatio
n
p
r
o
ce
s
s
es
(
E
m
p
lo
y
er
)
;
an
d
th
e
Data
Priv
ac
y
Pr
o
tectio
n
Dep
a
r
tm
en
t,
co
n
s
u
lted
to
en
s
u
r
e
co
m
p
lian
ce
with
leg
al
r
eg
u
latio
n
s
.
Fo
r
I
T
-
r
elate
d
m
atter
s
,
in
p
u
t
was
o
b
tain
e
d
f
r
o
m
I
n
f
o
r
m
atic
o
f
s
tak
eh
o
ld
er
s
,
th
e
d
ep
ar
tm
e
n
t
th
at
p
r
o
v
id
es
I
T
in
f
r
astru
ct
u
r
e,
s
o
f
twar
e,
an
d
s
er
v
ices
f
o
r
s
tu
d
en
ts
an
d
s
taf
f
.
R
eq
u
ir
em
e
n
ts
R
E
Q1
to
R
E
Q
4
p
er
tain
to
th
e
is
s
u
er
’
s
co
n
d
itio
n
s
-
th
at
is
,
th
e
d
em
an
d
s
Ac
ad
em
y
o
f
Gr
ad
u
ate
Stu
d
ies
an
d
L
ib
y
an
u
n
iv
er
s
ities
o
n
th
e
s
y
s
tem
.
R
E
Q5
to
R
E
Q6
co
n
ce
r
n
s
th
e
d
eliv
er
y
o
f
ce
r
tific
ates
in
d
ig
ital
f
o
r
m
at
to
s
tu
d
en
ts
.
Fin
ally
,
R
E
Q7
an
d
R
E
Q1
1
p
r
esen
t
r
e
q
u
ir
em
en
ts
f
o
r
co
m
p
an
ies
s
ee
k
in
g
(
Ver
i
f
ier
)
to
v
er
if
y
ce
r
tific
ates.
T
ab
le
3
.
R
u
les d
efin
ed
in
ac
ce
s
s
co
n
tr
o
l
I
ssu
e
r
(
A
c
a
d
e
my
o
f
G
r
a
d
u
a
t
e
S
t
u
d
i
e
s
a
n
d
L
i
b
y
a
n
U
n
i
v
e
r
si
t
i
e
s
)
R
EQ
1
A
u
t
h
e
n
t
i
c
a
t
i
o
n
a
n
d
a
u
t
h
o
r
i
z
a
t
i
o
n
:
i.
O
n
l
y
a
u
t
h
o
r
i
z
e
d
u
n
i
v
e
r
si
t
y
st
a
f
f
(
r
e
g
i
s
t
r
a
r
,
e
x
a
m
o
f
f
i
c
e
r
)
c
a
n
s
i
g
n
a
c
e
r
t
i
f
i
c
a
t
e
.
ii.
M
u
l
t
i
-
si
g
n
a
t
u
r
e
o
r
r
o
l
e
-
b
a
se
d
a
c
c
e
ss
c
o
n
t
r
o
l
(
R
B
A
C
)
o
n
t
h
e
i
ss
u
i
n
g
smar
t
c
o
n
t
r
a
c
t
.
i
i
i
.
A
b
i
l
i
t
y
t
o
r
e
v
o
k
e
a
c
e
r
t
i
f
i
c
a
t
e
(
a
c
a
d
e
mi
c
m
i
sc
o
n
d
u
c
t
,
d
e
g
r
e
e
a
n
n
u
l
m
e
n
t
)
.
i
v
.
M
a
i
n
t
a
i
n
a
p
u
b
l
i
c
l
y
v
e
r
i
f
i
a
b
l
e
r
e
v
o
c
a
t
i
o
n
l
i
s
t
o
r
st
a
t
u
s fi
e
l
d
o
n
-
c
h
a
i
n
.
R
EQ
2
C
e
r
t
i
f
i
c
a
t
e
c
r
e
a
t
i
o
n
:
i.
D
e
f
i
n
e
c
e
r
t
i
f
i
c
a
t
e
sc
h
e
m
a
(
s
t
u
d
e
n
t
n
a
me,
d
e
g
r
e
e
,
g
r
a
d
e
s
,
i
ss
u
a
n
c
e
d
a
t
e
,
u
n
i
q
u
e
I
D
,
h
a
sh
o
f
o
r
i
g
i
n
a
l
d
o
c
u
me
n
t
)
.
ii.
G
e
n
e
r
a
t
e
a
c
r
y
p
t
o
g
r
a
p
h
i
c
h
a
s
h
o
f
t
h
e
c
e
r
t
i
f
i
c
a
t
e
m
e
t
a
d
a
t
a
.
W
r
i
t
e
c
e
r
t
i
f
i
c
a
t
e
h
a
s
h
+
me
t
a
d
a
t
a
U
R
I
t
o
b
l
o
c
k
c
h
a
i
n
(
o
r
si
d
e
c
h
a
i
n
/
L
2
)
.
i
i
i
.
W
r
i
t
e
c
e
r
t
i
f
i
c
a
t
e
h
a
sh
+
m
e
t
a
d
a
t
a
U
R
I
t
o
b
l
o
c
k
c
h
a
i
n
(
o
r
s
i
d
e
c
h
a
i
n
/
L
2
)
.
i
v
.
A
t
t
a
c
h
u
n
i
v
e
r
s
i
t
y
’
s
d
i
g
i
t
a
l
s
i
g
n
a
t
u
r
e
(
p
r
i
v
a
t
e
k
e
y
)
.
R
EQ
3
D
a
t
a
p
r
i
v
a
c
y
&
c
o
mp
l
i
a
n
c
e
i.
S
t
o
r
e
o
n
l
y
mi
n
i
ma
l
d
a
t
a
o
n
-
c
h
a
i
n
(
h
a
sh
,
st
a
t
u
s,
t
i
me
st
a
mp
s)
;
st
o
r
e
f
u
l
l
c
e
r
t
i
f
i
c
a
t
e
o
f
f
-
c
h
a
i
n
(
I
P
F
S
,
c
l
o
u
d
)
w
i
t
h
e
n
c
r
y
p
t
i
o
n
.
ii.
C
o
m
p
l
y
w
i
t
h
G
D
P
R
/
F
E
R
P
A
–
a
l
l
o
w
st
u
d
e
n
t
d
a
t
a
d
e
l
e
t
i
o
n
r
e
q
u
e
st
s w
h
e
r
e
p
o
ssi
b
l
e
.
R
EQ
4
A
u
d
i
t
t
r
a
i
l
Lo
g
e
v
e
r
y
i
ssu
a
n
c
e
,
u
p
d
a
t
e
,
a
n
d
r
e
v
o
c
a
t
i
o
n
e
v
e
n
t
w
i
t
h
t
i
mes
t
a
m
p
a
n
d
s
i
g
n
e
r
i
d
e
n
t
i
t
y
.
H
o
l
d
e
r
(
S
t
u
d
e
n
t
)
R
EQ
5
W
a
l
l
e
t
&
k
e
y
m
a
n
a
g
e
me
n
t
i.
P
r
i
mary
r
o
l
e
:
W
a
l
l
e
t
&
k
e
y
ma
n
a
g
e
m
e
n
t
b
y
n
o
n
-
c
u
s
t
o
d
i
a
l
w
a
l
l
e
t
(
m
o
b
i
l
e
o
r
w
e
b
)
t
o
st
o
r
e
p
r
i
v
a
t
e
k
e
y
s.
ii.
A
b
i
l
i
t
y
t
o
B
a
c
k
u
p
& re
c
o
v
e
r
y
m
e
c
h
a
n
i
sm
R
EQ
6
C
e
r
t
i
f
i
c
a
t
e
r
e
c
e
p
t
i
o
n
i.
R
e
c
e
i
v
e
n
o
t
i
f
i
c
a
t
i
o
n
w
h
e
n
c
e
r
t
i
f
i
c
a
t
e
i
s i
ss
u
e
d
.
ii.
V
e
r
i
f
y
i
ss
u
e
r
’
s si
g
n
a
t
u
r
e
a
n
d
c
e
r
t
i
f
i
c
a
t
e
i
n
t
e
g
r
i
t
y
o
n
-
c
h
a
i
n
.
i
i
i
.
R
e
q
u
e
st
c
e
r
t
i
f
i
c
a
t
e
d
e
l
e
t
i
o
n
i
f
a
l
l
o
w
e
d
b
y
l
a
w
.
V
e
r
i
f
i
e
r
(
E
mp
l
o
y
e
r
)
R
EQ
7
V
e
r
i
f
i
c
a
t
i
o
n
i
n
t
e
r
f
a
c
e
i.
En
t
e
r
c
e
r
t
i
f
i
c
a
t
e
I
D
,
sca
n
Q
R
c
o
d
e
,
o
r
r
e
c
e
i
v
e
a
s
h
a
r
e
a
b
l
e
l
i
n
k
f
r
o
m
st
u
d
e
n
t
.
ii.
A
u
t
o
ma
t
i
c
a
l
l
y
c
h
e
c
k
I
ssu
e
r
’
s p
u
b
l
i
c
k
e
y
.
i
i
i
.
A
u
t
o
ma
t
i
c
a
l
l
y
c
h
e
c
k
C
e
r
t
i
f
i
c
a
t
e
h
a
s
h
mat
c
h
e
s
o
n
-
c
h
a
i
n
r
e
c
o
r
d
R
EQ
8
B
a
t
c
h
v
e
r
i
f
i
c
a
t
i
o
n
i.
U
p
l
o
a
d
m
u
l
t
i
p
l
e
c
e
r
t
i
f
i
c
a
t
e
I
D
s o
r
h
a
s
h
e
s f
o
r
b
u
l
k
v
e
r
i
f
i
c
a
t
i
o
n
.
R
EQ
9
Ta
mp
e
r
d
e
t
e
c
t
i
o
n
i.
D
i
sp
l
a
y
c
l
e
a
r
r
e
s
u
l
t
:
Va
l
i
d
,
Re
v
o
k
e
d
,
Mi
sm
a
t
c
h
,
o
r
I
ssu
e
r Un
k
n
o
w
n
.
ii.
S
h
o
w
o
r
i
g
i
n
a
l
met
a
d
a
t
a
(
d
e
g
r
e
e
n
a
me
,
g
r
a
d
u
a
t
i
o
n
d
a
t
e
)
f
r
o
m
o
f
f
-
c
h
a
i
n
st
o
r
a
g
e
.
R
EQ
1
0
Tr
u
st
ma
n
a
g
e
m
e
n
t
i.
M
a
i
n
t
a
i
n
a
t
r
u
s
t
e
d
i
ssu
e
r
r
e
g
i
s
t
r
y
(
w
h
i
t
e
l
i
st
o
f
u
n
i
v
e
r
s
i
t
y
D
I
D
s/
p
u
b
l
i
c
k
e
y
s)
.
ii.
A
l
l
o
w
c
u
st
o
m
t
r
u
s
t
p
o
l
i
c
i
e
s.
R
EQ
1
1
A
u
d
i
t
l
o
g
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_
a
.
3
.
2
.
1
.
Appl
ica
t
io
n
a
nd
us
er
i
nte
rf
a
ce
la
y
er
T
h
is
is
th
e
o
u
ter
m
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s
t
lay
er
,
d
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tly
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ter
ac
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with
th
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th
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p
r
im
ar
y
s
tak
eh
o
l
d
er
s
in
ter
ac
t:
u
n
iv
er
s
ities
(
is
s
u
er
s
)
,
s
tu
d
en
ts
(
h
o
ld
er
s
)
,
a
n
d
em
p
lo
y
er
s
/v
er
i
f
ier
s
.
I
ts
p
r
im
ar
y
f
u
n
ctio
n
is
to
p
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o
v
i
d
e
in
tu
itiv
e
an
d
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ce
s
s
ib
le
in
ter
f
ac
es f
o
r
v
ar
io
u
s
cr
ed
en
tial
-
r
elate
d
o
p
e
r
a
tio
n
s
v
ia
web
an
d
m
o
b
ile
a
p
p
l
icatio
n
s
.
−
C
r
ed
en
tial
is
s
u
an
ce
p
o
r
tal
(
W
eb
Ap
p
)
:
T
h
is
web
ap
p
licatio
n
is
u
s
ed
b
y
u
n
i
v
er
s
ities
to
cr
ea
te
an
d
is
s
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e
d
ig
ital
ce
r
tific
ate
s
.
I
t
s
er
v
es
as
th
e
p
r
im
a
r
y
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n
ter
f
ac
e
f
o
r
u
n
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er
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ity
ad
m
in
is
tr
ato
r
s
to
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n
p
u
t
ce
r
tific
ate
d
ata
(
s
tu
d
en
t
n
am
e,
co
u
r
s
e,
g
r
ad
es,
d
eg
r
ee
awa
r
d
e
d
)
in
f
o
r
m
ats
J
SON
o
r
PDF.
T
h
is
p
o
r
t
al
in
itiates
th
e
p
r
o
ce
s
s
o
f
g
e
n
er
atin
g
a
v
er
if
ia
b
le
cr
ed
en
tial.
−
Dig
ital
wallet
(
Mo
b
ile
Ap
p
)
:
Desig
n
ed
f
o
r
s
tu
d
en
ts
,
t
h
is
m
o
b
ile
ap
p
licatio
n
ac
ts
as
a
s
ec
u
r
e
r
e
p
o
s
ito
r
y
f
o
r
th
eir
v
er
if
ia
b
le
cr
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en
tial
s
.
Stu
d
en
ts
,
as
h
o
ld
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s
,
r
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eiv
e
an
d
s
to
r
e
th
eir
d
ig
ital
ce
r
t
if
icate
s
in
th
i
s
wallet.
I
t
f
ac
ilit
ates
in
ter
ac
tio
n
with
th
e
s
y
s
tem
a
n
d
API
ca
l
ls
,
allo
win
g
s
tu
d
en
ts
to
m
an
a
g
e
an
d
p
r
esen
t
th
eir
cr
ed
en
tials
as n
ee
d
ed
.
−
C
r
ed
en
tial
v
er
if
icatio
n
p
o
r
tal
(
W
eb
Ap
p
)
:
T
h
is
web
ap
p
l
icatio
n
is
u
tili
ze
d
b
y
em
p
lo
y
er
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o
r
o
th
e
r
v
er
if
ier
s
to
co
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f
ir
m
th
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t
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ticity
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s
tu
d
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.
Ver
if
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s
ca
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r
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tal
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in
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ap
h
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v
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v
alid
r
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lt.
3
.
2
.
2
.
Appl
ica
t
io
n
a
nd
us
er
i
nte
rf
a
ce
la
y
er
T
h
is
is
th
e
o
u
ter
m
o
s
t
lay
er
,
d
ir
ec
tly
in
ter
ac
tin
g
with
th
e
th
r
ee
p
r
im
ar
y
s
tak
eh
o
l
d
er
s
in
ter
ac
t:
u
n
iv
er
s
ities
(
is
s
u
er
s
)
,
s
tu
d
en
ts
(
h
o
ld
er
s
)
,
a
n
d
em
p
lo
y
er
s
/v
er
i
f
ier
s
.
I
ts
p
r
im
ar
y
f
u
n
ctio
n
is
to
p
r
o
v
i
d
e
in
tu
itiv
e
an
d
ac
ce
s
s
ib
le
in
ter
f
ac
es f
o
r
v
ar
io
u
s
cr
ed
en
tial
-
r
elate
d
o
p
e
r
a
tio
n
s
v
ia
web
an
d
m
o
b
i
le
a
p
p
l
icatio
n
s
.
−
C
r
ed
en
tial
is
s
u
an
ce
p
o
r
tal
(
W
eb
Ap
p
)
:
T
h
is
web
ap
p
licatio
n
is
u
s
ed
b
y
u
n
i
v
er
s
ities
to
cr
ea
te
an
d
is
s
u
e
d
ig
ital
ce
r
tific
ates.
I
t
s
er
v
es
as
th
e
p
r
im
a
r
y
i
n
ter
f
ac
e
f
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r
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er
s
ity
ad
m
in
is
tr
ato
r
s
to
i
n
p
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t
ce
r
tific
ate
Evaluation Warning : The document was created with Spire.PDF for Python.
I
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N:
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2
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2
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I
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,
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l.
15
,
No
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4
,
Dec
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b
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20
26
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1
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1
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d
ata
(
s
tu
d
en
t
n
am
e,
co
u
r
s
e,
g
r
ad
es,
d
eg
r
ee
awa
r
d
e
d
)
in
f
o
r
m
ats
J
SON
o
r
PDF.
T
h
is
p
o
r
t
al
in
itiates
th
e
p
r
o
ce
s
s
o
f
g
e
n
er
atin
g
a
v
er
if
ia
b
le
cr
ed
en
tial.
−
Dig
ital
wallet
(
Mo
b
ile
Ap
p
)
:
Desig
n
ed
f
o
r
s
tu
d
en
ts
,
t
h
is
m
o
b
ile
ap
p
licatio
n
ac
ts
as
a
s
ec
u
r
e
r
e
p
o
s
ito
r
y
f
o
r
th
eir
v
er
if
ia
b
le
cr
ed
en
tial
s
.
Stu
d
en
ts
,
as
h
o
ld
er
s
,
r
ec
eiv
e
an
d
s
to
r
e
th
eir
d
ig
ital
ce
r
t
if
icate
s
in
th
i
s
wallet.
I
t
f
ac
ilit
ates
in
ter
ac
tio
n
with
th
e
s
y
s
tem
a
n
d
API
ca
l
ls
,
allo
win
g
s
tu
d
en
ts
to
m
an
a
g
e
an
d
p
r
esen
t
th
eir
cr
ed
en
tials
as n
ee
d
ed
.
−
C
r
ed
en
tial
v
er
if
icatio
n
p
o
r
tal
(
W
eb
Ap
p
)
:
T
h
is
web
ap
p
l
icatio
n
is
u
tili
ze
d
b
y
em
p
lo
y
er
s
o
r
o
th
e
r
v
er
if
ier
s
to
co
n
f
ir
m
th
e
au
t
h
en
ticity
an
d
v
alid
ity
o
f
ac
ad
em
ic
cr
ed
en
tials
p
r
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ted
b
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tu
d
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ts
.
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if
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s
ca
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b
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tal
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u
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b
lo
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c
h
ain
f
r
am
ewo
r
k
ar
ch
itectu
r
e
f
o
r
h
i
g
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er
ed
u
ca
tio
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ce
r
tific
ates
3
.
2
.
3
.
I
dentit
y
a
nd
s
y
s
t
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ma
na
g
em
ent
la
y
er
T
h
is
lay
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ac
ts
as
an
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m
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"Or
ch
estra
to
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b
etwe
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t
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u
s
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f
ac
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g
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p
p
licatio
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s
an
d
th
e
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lo
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in
f
r
astru
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u
r
e.
I
t
h
an
d
les
id
en
tity
m
an
a
g
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en
t
,
API
in
ter
ac
tio
n
s
,
an
d
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th
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ticatio
n
,
en
s
u
r
i
n
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r
e
an
d
c
o
n
tr
o
lled
ac
c
ess
to
th
e
s
y
s
tem
.
−
DI
D
m
an
ag
em
e
n
t
s
y
s
tem
:
T
h
is
s
y
s
tem
is
r
esp
o
n
s
ib
le
f
o
r
m
an
ag
in
g
DI
Ds,
wh
ich
ar
e
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n
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ty
p
e
o
f
id
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tifie
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th
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g
lo
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ally
u
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i
q
u
e,
r
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lv
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le,
a
n
d
cr
y
p
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ap
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ically
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er
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le.
W
3
C
DI
Ds
ar
e
u
s
ed
to
r
ep
r
esen
t
th
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i
d
en
titi
es
o
f
is
s
u
er
s
(
u
n
iv
er
s
ities
)
an
d
h
o
ld
er
s
(
s
tu
d
en
ts
)
in
a
d
ec
en
tr
al
ized
m
an
n
e
r
.
T
h
is
s
y
s
tem
f
ac
ilit
ate
s
th
e
c
r
ea
tio
n
,
u
p
d
atin
g
,
an
d
r
eso
lu
tio
n
o
f
DI
Ds,
o
f
ten
an
ch
o
r
i
n
g
DI
D/Hash
in
f
o
r
m
atio
n
to
th
e
b
lo
ck
c
h
ain
(
B
C
)
f
o
r
im
m
u
tab
ilit
y
.
−
API
g
atew
ay
(
R
E
ST/Gr
ap
h
Q
L
)
:
T
h
e
API
Gate
way
s
er
v
es
as
th
e
s
in
g
le
-
en
t
r
y
p
o
in
t
f
o
r
a
ll
in
ter
ac
tio
n
s
an
d
API
ca
lls
f
r
o
m
t
h
e
Ap
p
licatio
n
&
User
I
n
ter
f
ac
e
L
ay
e
r
to
th
e
u
n
d
er
ly
in
g
s
er
v
ices.
I
t
s
u
p
p
o
r
ts
b
o
th
R
E
ST
an
d
Gr
ap
h
QL
p
r
o
to
co
ls
,
en
ab
lin
g
f
lex
ib
le
an
d
ef
f
icie
n
t
d
ata
ex
ch
a
n
g
e.
C
r
ed
e
n
tials
,
o
f
ten
in
J
W
T
f
o
r
m
at,
ar
e
p
ass
ed
th
r
o
u
g
h
th
i
s
g
atew
ay
.
−
Au
th
en
ticatio
n
m
o
d
u
le
(
OI
DC
/SAML
)
:
T
h
is
m
o
d
u
l
e
h
an
d
les
u
s
er
au
th
en
ticatio
n
an
d
au
th
o
r
izatio
n
.
I
t
s
u
p
p
o
r
ts
s
tan
d
ar
d
p
r
o
to
c
o
ls
lik
e
Op
en
I
D
C
o
n
n
ec
t
(
OI
D
C
)
an
d
s
ec
u
r
ity
ass
er
tio
n
m
a
r
k
u
p
lan
g
u
a
g
e
(
SAML
)
to
s
ec
u
r
ely
v
er
if
y
th
e
id
en
tity
o
f
u
s
er
s
(
u
n
iv
er
s
itie
s
,
s
tu
d
en
ts
,
v
er
if
ier
s
)
ac
ce
s
s
in
g
th
e
s
y
s
tem
.
T
h
i
s
en
s
u
r
es
th
at
o
n
ly
au
th
o
r
ized
en
titi
es
ca
n
p
er
f
o
r
m
s
p
e
cif
ic
ac
tio
n
s
,
s
u
ch
as
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s
u
in
g
ce
r
tific
ates
o
r
in
itiatin
g
v
er
if
icatio
n
r
eq
u
ests
.
3
.
2
.
4
.
T
rus
t
eng
ine la
y
er
(
b
lo
ck
cha
in
a
nd
s
m
a
rt
co
ntr
a
ct
s
)
T
h
is
is
th
e
co
r
e
o
f
th
e
b
lo
ck
ch
ain
s
y
s
tem
,
wh
er
e
th
e
im
m
u
tab
ilit
y
,
tr
an
s
p
ar
en
c
y
,
an
d
tr
u
s
t
m
ec
h
an
is
m
s
ar
e
en
f
o
r
ce
d
.
I
t
c
o
m
p
r
is
es
o
f
f
-
c
h
ain
s
to
r
a
g
e,
a
h
ash
in
g
m
o
d
u
le,
a
n
d
t
h
e
b
lo
c
k
ch
ain
n
etwo
r
k
wit
h
its
s
m
ar
t c
o
n
tr
ac
ts
.
−
Of
f
-
ch
ain
s
to
r
ag
e
:
W
h
ile
th
e
b
lo
ck
ch
a
in
s
to
r
es
im
m
u
tab
le
p
r
o
o
f
s
,
th
e
ac
tu
al,
f
u
ll
ce
r
tific
ate
ar
tifa
cts
ar
e
s
to
r
ed
o
f
f
-
ch
ain
.
T
h
is
ap
p
r
o
ac
h
is
cr
u
cial
f
o
r
m
an
ag
i
n
g
d
ata
p
r
iv
ac
y
a
n
d
h
a
n
d
lin
g
lar
g
er
d
a
ta
v
o
lu
m
es.
−
Hash
in
g
m
o
d
u
le
(
SHA
-
2
5
6
)
:
T
h
is
m
o
d
u
le
tak
es
th
e
ce
r
t
if
icate
d
ata
(
f
r
o
m
o
f
f
-
c
h
ain
s
to
r
ag
e)
an
d
g
en
er
ates
a
u
n
iq
u
e
cr
y
p
to
g
r
a
p
h
ic
h
ash
u
s
in
g
alg
o
r
ith
m
s
l
ik
e
SHA
-
2
5
6
.
T
h
is
h
ash
ac
t
s
as
a
d
ig
ital
f
in
g
er
p
r
in
t
o
f
th
e
ce
r
tific
ate.
An
y
alter
atio
n
to
th
e
ce
r
tific
at
e
d
ata,
ev
en
a
s
in
g
le
ch
ar
ac
te
r
,
wo
u
ld
r
esu
lt
in
a
co
m
p
letely
d
if
f
er
e
n
t h
ash
,
th
u
s
en
s
u
r
in
g
d
ata
in
teg
r
ity
a
n
d
tam
p
er
-
p
r
o
o
f
in
g
.
Evaluation Warning : The document was created with Spire.PDF for Python.
I
n
t J I
n
f
&
C
o
m
m
u
n
T
ec
h
n
o
l
I
SS
N:
2252
-
8
7
7
6
Desig
n
fr
a
mewo
r
k
fo
r
h
ig
h
er e
d
u
ca
tio
n
ce
r
tifi
ca
tes u
s
in
g
b
lo
ck
ch
a
in
tec
h
n
o
lo
g
y
(
S
a
lem
S
.
M.
K
h
a
lifa
)
1807
−
B
lo
ck
ch
ain
n
etwo
r
k
(
H
y
p
er
le
d
g
er
Fab
r
ic/Per
m
is
s
io
n
ed
)
:
T
h
is
is
th
e
d
is
tr
ib
u
ted
le
d
g
er
te
ch
n
o
lo
g
y
th
at
u
n
d
er
p
in
s
th
e
en
tire
s
y
s
tem
.
T
h
e
b
lo
ck
c
h
ain
n
etwo
r
k
m
ain
tain
s
a
L
ed
g
er
th
at
r
ec
o
r
d
s
k
e
y
in
f
o
r
m
atio
n
f
o
r
ea
ch
c
er
tific
ate,
in
clu
d
i
n
g
:
•
C
er
tific
ate
Hash
(
An
ch
o
r
)
:
T
h
e
u
n
iq
u
e
h
ash
o
f
th
e
ce
r
tific
at
e,
s
er
v
in
g
as
an
im
m
u
tab
le
a
n
ch
o
r
o
n
th
e
b
lo
ck
c
h
ain
.
•
I
s
s
u
er
DI
D:
T
h
e
DI
D
o
f
t
h
e
is
s
u
in
g
u
n
iv
e
r
s
ity
.
•
R
ev
o
ca
tio
n
Statu
s
: A
f
lag
in
d
i
ca
tin
g
wh
eth
er
th
e
ce
r
tific
ate
h
as b
ee
n
r
e
v
o
k
e
d
.
•
T
im
estam
p
: T
h
e
tim
e
o
f
ce
r
tif
icate
is
s
u
an
ce
o
r
last
u
p
d
ate.
−
Sm
ar
t
c
o
n
tr
ac
ts
(
C
h
ain
c
o
d
e)
:
T
h
ese
ar
e
s
elf
-
ex
ec
u
tin
g
c
o
n
tr
ac
ts
with
th
e
ter
m
s
o
f
t
h
e
ag
r
ee
m
en
t
d
ir
ec
tly
wr
itten
in
t
o
co
d
e.
I
n
th
is
f
r
am
ew
o
r
k
,
s
m
ar
t
co
n
tr
ac
ts
(
o
f
ten
r
ef
er
r
ed
t
o
as
ch
ain
co
d
e
i
n
Hy
p
er
led
g
e
r
Fab
r
ic)
d
ef
in
e
th
e
co
r
e
lo
g
ic
f
o
r
c
r
ed
en
tial m
a
n
ag
em
en
t:
•
I
s
s
u
eCer
tific
ate
(
)
:
A
f
u
n
ctio
n
th
at
r
ec
o
r
d
s
th
e
ce
r
tific
ate
h
ash
,
is
s
u
er
DI
D,
an
d
o
th
er
r
elev
an
t
m
etad
ata
o
n
to
t
h
e
b
lo
c
k
ch
ain
l
ed
g
er
.
•
R
ev
o
k
eCer
tific
ate
(
)
:
A
f
u
n
cti
o
n
th
at
u
p
d
ates
th
e
r
ev
o
ca
tio
n
s
tatu
s
o
f
a
s
p
ec
if
ic
ce
r
tific
ate
o
n
th
e
led
g
er
,
ef
f
ec
tiv
ely
in
v
alid
atin
g
it.
•
Ver
if
y
C
er
tific
ate
(
)
:
A
f
u
n
ctio
n
th
at
allo
ws
q
u
er
y
i
n
g
th
e
b
lo
ck
ch
ain
led
g
er
to
c
h
ec
k
th
e
e
x
is
ten
ce
an
d
s
tatu
s
o
f
a
ce
r
tific
ate
h
ash
.
3
.
2
.
5
.
Ver
if
ica
t
io
n
l
a
y
er
T
h
is
f
in
al
lay
er
is
d
ed
icate
d
to
th
e
p
r
o
ce
s
s
o
f
v
er
if
y
i
n
g
t
h
e
au
th
e
n
ticity
an
d
v
alid
ity
o
f
a
d
ig
ital
ce
r
tific
ate,
p
r
o
v
i
d
in
g
a
clea
r
o
u
tco
m
e
to
th
e
v
er
if
ier
.
−
Glo
b
al
r
ev
o
ca
tio
n
lis
t
(
Sm
ar
t
co
n
tr
ac
t
tab
le
)
:
T
h
is
co
m
p
o
n
en
t,
o
f
ten
im
p
lem
e
n
ted
as
a
s
m
ar
t
co
n
tr
ac
t
tab
le
o
n
th
e
b
lo
ck
c
h
ain
,
m
ain
t
ain
s
a
co
m
p
r
eh
e
n
s
iv
e
lis
t
o
f
a
ll
r
ev
o
k
ed
ce
r
tific
ates.
W
h
en
a
ce
r
tific
ate
is
r
ev
o
k
e
d
v
ia
th
e
R
ev
o
k
eCer
ti
f
icate
(
)
s
m
ar
t
co
n
tr
ac
t
f
u
n
ct
io
n
,
its
s
tatu
s
i
s
u
p
d
ated
h
er
e.
T
h
is
lis
t
i
s
cr
u
cial
f
o
r
e
n
s
u
r
in
g
th
at
ev
en
if
a
ce
r
tific
ate
was o
n
ce
v
alid
,
i
ts
cu
r
r
en
t statu
s
ca
n
b
e
ac
cu
r
at
ely
ch
ec
k
ed
.
−
Ver
if
icatio
n
r
esu
lt
(
C
r
y
p
to
g
r
ap
h
ically
v
alid
/in
v
alid
)
:
T
h
is
is
th
e
u
ltima
te
o
u
tp
u
t
o
f
th
e
v
er
if
icatio
n
p
r
o
ce
s
s
.
W
h
en
a
n
em
p
lo
y
e
r
o
r
v
e
r
if
ier
s
u
b
m
its
a
c
r
ed
en
ti
al,
th
e
s
y
s
tem
c
h
ec
k
s
its
h
as
h
ag
ain
s
t
t
h
e
b
lo
ck
ch
ain
led
g
er
a
n
d
cr
o
s
s
-
r
ef
er
en
ce
s
it
with
th
e
Glo
b
al
R
ev
o
ca
tio
n
L
is
t.
B
ased
o
n
th
ese
ch
ec
k
s
,
a
d
ef
in
itiv
e
r
esu
lt
is
p
r
o
v
id
e
d
,
i
n
d
icatin
g
wh
eth
er
th
e
cr
ed
e
n
t
ial
is
cr
y
p
to
g
r
ap
h
ically
v
al
id
(
au
th
en
tic
an
d
n
o
t
r
ev
o
k
ed
)
o
r
in
v
alid
(
tam
p
er
ed
with
o
r
r
ev
o
k
ed
)
.
T
h
is
r
esu
lt
p
r
o
v
id
es
a
h
i
g
h
lev
el
o
f
tr
u
s
t
an
d
ass
u
r
an
ce
in
th
e
ac
ad
em
ic
cr
e
d
en
tial.
3
.
3
.
S
m
a
rt
c
o
ntr
a
ct
(
Cha
inco
de)
d
ev
elo
pm
ent
T
h
is
s
ec
tio
n
d
is
cu
s
s
e
s
f
o
r
m
al
m
ath
em
atica
l
alg
o
r
ith
m
s
f
o
r
two
cr
itical
p
r
o
ce
s
s
es
with
in
a
b
lo
ck
ch
ain
-
b
ased
h
ig
h
er
ed
u
c
atio
n
ce
r
tific
ate
f
r
am
ewo
r
k
:
th
e
en
r
o
llm
en
t
o
f
a
d
m
in
is
tr
ato
r
s
an
d
u
s
er
s
,
an
d
th
e
s
u
b
s
eq
u
en
t
is
s
u
an
ce
o
f
ce
r
tif
icate
s
v
ia
th
e
I
s
s
u
eCer
tific
ate
(
)
f
u
n
ctio
n
.
T
h
ese
alg
o
r
ith
m
s
ar
e
d
esig
n
e
d
t
o
p
r
o
v
i
d
e
a
p
r
ec
is
e,
s
tep
-
by
-
s
tep
m
eth
o
d
o
l
o
g
y
,
lev
e
r
ag
in
g
cr
y
p
to
g
r
a
p
h
ic
p
r
i
n
cip
les
an
d
DI
D
s
to
en
s
u
r
e
s
ec
u
r
ity
,
au
th
en
ticity
,
a
n
d
in
te
g
r
ity
.
3
.
3
.
1
.
Alg
o
rit
hm
1
f
o
r
a
dm
in
/us
er
enro
llm
ent
T
h
e
f
ir
s
t
s
tep
o
f
th
is
alg
o
r
it
h
m
aim
s
to
en
s
u
r
e
th
e
allo
c
atio
n
o
f
a
u
n
iq
u
e
an
d
c
r
y
p
to
g
r
ap
h
ically
s
ec
u
r
e
id
en
tity
wh
et
h
er
an
ad
m
in
is
tr
ato
r
,
an
is
s
u
in
g
in
s
titu
tio
n
,
a
s
tu
d
e
n
t
(
h
o
ld
er
)
,
o
r
a
v
er
if
ier
.
T
h
e
in
itial
s
tep
in
v
o
lv
es
cr
ea
tin
g
a
c
r
y
p
t
o
g
r
ap
h
ic
k
ey
p
air
:
a
p
u
b
lic
k
e
y
(
PK{u
_
n
ew}
)
a
n
d
a
c
o
r
r
esp
o
n
d
in
g
p
r
iv
ate
k
ey
(
SK {
u
_
n
ew}
)
b
y
a
d
e
d
icate
d
k
ey
m
an
a
g
em
en
t ser
v
ice.
I
n
th
e
Seco
n
d
s
tep
,
f
o
llo
win
g
k
ey
p
air
g
en
e
r
atio
n
,
a
DI
D_
u
_
n
ew
is
c
r
ea
ted
f
o
r
u
_
n
ew.
T
h
e
C
r
ea
teDI
D
(
PK_
u
_
n
ew)
f
u
n
ctio
n
tak
es
th
e
p
u
b
lic
k
ey
as
in
p
u
t
an
d
c
o
n
s
tr
u
cts
a
DI
D.
T
h
is
DI
D
is
a
p
er
s
is
ten
t,
g
lo
b
ally
u
n
iq
u
e
id
e
n
tifie
r
th
at
is
r
eso
lv
ab
le
to
a
DI
D
Do
cu
m
en
t,
wh
ich
co
n
tai
n
s
in
f
o
r
m
atio
n
a
b
o
u
t
h
o
w
to
in
ter
ac
t w
ith
th
e
DI
D
s
u
b
ject,
in
clu
d
i
n
g
th
eir
p
u
b
lic
k
ey
s
.
I
n
th
e
th
i
r
d
s
tep
,
t
h
e
u
s
er
'
s
au
th
en
ticatio
n
cr
e
d
en
tials
(
A
u
th
_
C
r
ed
s
)
,
s
u
ch
as
a
u
s
er
n
a
m
e
an
d
a
h
ash
ed
p
a
s
s
wo
r
d
,
ar
e
s
ec
u
r
el
y
s
to
r
ed
in
an
Au
th
_
DB
.
T
h
i
s
d
atab
ase
is
d
i
s
tin
ct
f
r
o
m
th
e
b
lo
ck
ch
ain
an
d
is
ty
p
ically
a
tr
ad
itio
n
al,
s
ec
u
r
e
d
atab
ase
m
an
ag
e
d
b
y
th
e
s
y
s
tem
o
p
e
r
ato
r
.
Au
th
_
C
r
ed
s
o
f
f
e
r
a
m
o
r
e
u
s
er
-
f
r
ien
d
l
y
au
th
en
ticatio
n
m
ec
h
an
is
m
f
o
r
d
a
y
-
to
-
d
ay
i
n
ter
ac
t
io
n
s
with
o
f
f
-
ch
ain
s
er
v
ices,
as
well
a
s
s
ep
ar
atio
n
o
f
Au
th
_
DB
f
r
o
m
th
e
b
lo
ck
ch
ain
p
r
o
tects
s
en
s
itiv
e
lo
g
in
in
f
o
r
m
atio
n
f
r
o
m
b
ein
g
ex
p
o
s
ed
o
n
a
p
u
b
lic
led
g
e
r
.
in
s
tep
f
o
u
r
,
b
ased
o
n
th
e
R
o
le_
u
_
n
ew
s
p
ec
if
ied
d
u
r
i
n
g
en
r
o
llm
en
t,
t
h
e
s
y
s
tem
ass
ig
n
s
th
e
ap
p
r
o
p
r
iate
r
o
le
to
u
_
n
ew
an
d
r
eg
is
ter
s
th
eir
DI
D
_
u
_
n
ew
in
th
e
r
elev
a
n
t
r
eg
i
s
tr
y
.
T
h
is
in
v
o
lv
es
co
n
d
itio
n
al
lo
g
ic:
−
I
f
R
o
le_
u
_
n
ew
=
'
Ad
m
in
'
:
T
h
e
DI
D_
u
_
n
ew
is
ad
d
e
d
to
R
eg
_
A
(
Ad
m
i
n
is
tr
ato
r
R
eg
is
tr
y
)
,
an
d
t
h
e
u
s
er
'
s
r
o
le
is
s
et
to
'
Ad
m
in
'
in
Au
th
_
DB
.
T
h
is
g
r
an
ts
u
_
n
ew
ad
m
in
is
tr
ativ
e
p
r
iv
ileg
es with
in
th
e
s
y
s
tem
.
Evaluation Warning : The document was created with Spire.PDF for Python.
I
SS
N:
2
2
5
2
-
8
7
7
6
I
n
t J I
n
f
&
C
o
m
m
u
n
T
ec
h
n
o
l
,
Vo
l.
15
,
No
.
4
,
Dec
em
b
er
20
26
:
1
8
0
0
-
1
8
1
5
1808
−
I
f
R
o
le_
u
_
n
ew
=
'
I
s
s
u
er
':
T
h
e
DI
D_
u
_
n
ew
is
a
d
d
ed
to
R
eg
_
I
(
I
s
s
u
er
R
eg
is
tr
y
)
,
an
d
th
e
u
s
er
'
s
r
o
le
is
s
et
to
'
I
s
s
u
er
'
in
Au
th
_
DB
.
T
h
is
au
th
o
r
izes u
_
n
ew
(
r
ep
r
esen
tin
g
an
in
s
titu
tio
n
)
to
is
s
u
e
ce
r
tific
ates.
−
I
f
R
o
le_
u
_
n
ew
=
'
Ho
ld
er
'
o
r
'Ve
r
if
ier
'
:
T
h
e
u
s
er
'
s
r
o
le
i
s
s
i
m
p
ly
s
et
in
Au
th
_
DB
.
Ho
ld
er
s
an
d
Ver
if
ier
s
ty
p
ically
d
o
n
o
t
r
eq
u
ir
e
r
e
g
is
tr
atio
n
in
a
s
ep
a
r
ate
DI
D
r
eg
is
tr
y
b
e
y
o
n
d
th
eir
in
itial
DI
D
cr
e
atio
n
,
as
th
ei
r
p
r
im
ar
y
in
ter
ac
tio
n
is
with
th
e
ir
o
wn
d
ig
ital
wa
llet
o
r
a
v
er
if
icatio
n
p
o
r
tal.
R
o
le
-
b
ased
ac
c
ess
co
n
tr
o
l
is
cr
itical
f
o
r
m
ain
tain
i
n
g
th
e
s
ec
u
r
ity
an
d
in
teg
r
ity
o
f
th
e
s
y
s
tem
,
th
u
s
,
to
p
r
ev
e
n
t
u
n
au
th
o
r
ized
en
titi
es
f
r
o
m
im
p
er
s
o
n
atin
g
leg
itima
te
ad
m
in
is
tr
ato
r
s
o
r
in
s
titu
tio
n
s
,
th
e
s
y
s
tem
ca
n
cr
y
p
t
o
g
r
a
p
h
ic
ally
v
er
if
y
th
e
au
th
o
r
ity
o
f
an
en
tity
b
ef
o
r
e
allo
win
g
th
em
to
p
er
f
o
r
m
s
en
s
itiv
e
o
p
er
atio
n
s
(
is
s
u
in
g
o
r
r
ev
o
k
in
g
ce
r
tific
ates)
.
Fin
ally
,
th
e
al
g
o
r
ith
m
co
n
clu
d
es
b
y
r
et
u
r
n
in
g
a
Su
cc
ess
o
r
Failu
r
e
s
tatu
s
,
a
lo
n
g
with
th
e
g
en
er
ated
DI
D_
u
_
n
ew,
PK_
u
_
n
ew,
an
d
SK_
u
_
n
ew.
I
n
a
r
e
al
-
wo
r
ld
im
p
lem
en
tatio
n
,
SK_
u
_
n
ew
wo
u
ld
ty
p
ically
b
e
r
etu
r
n
ed
d
ir
ec
tly
to
th
e
u
s
er
'
s
s
ec
u
r
e
clien
t
(
d
ig
ital
wallet)
an
d
n
o
t
s
to
r
ed
b
y
th
e
s
y
s
tem
its
elf
,
wh
er
e
th
e
r
etu
r
n
o
f
Su
cc
ess
in
d
icate
s
th
at
th
e
u
s
er
h
as
b
ee
n
s
u
cc
ess
f
u
lly
o
n
b
o
ar
d
ed
an
d
t
h
eir
id
en
tity
estab
lis
h
ed
with
in
th
e
s
y
s
tem
.
Alg
o
r
ith
m
1
.
Fo
r
ad
m
i
n
/u
s
er
e
n
r
o
llm
en
t
Input:
u_new: The new user to be enrolled.
Role_u_new: The intended role for u_new ('Admin', 'Issuer', 'Holder').
Auth_Creds
: Authentication credentials for u_new (username, password, or other secure
authentication tokens).
Output:
DID_u_new: The Decentralized Identifier generated for u_new.
PK_u_new, SK_u_new: The public and secret key pair for u_new.
Success or Failure status
.
Steps:
1. Generate Key Pair: Generate a new public
-
secret key pair for u_new:
(PK_u_new, SK_u_new) ← GenerateKeyPair ()
2. Create DID: Create a new Decentralized Identifier for u_new:
DID_u_new ← CreateDID (PK_u_new)
Optionally, anchor DID_u_new or its h
ash to a public blockchain for global
resolvability and immutability.
3. Store Authentication Credentials: Securely store Auth_Creds for u_new in Auth_DB.
4. Assign Role and Register DID:
If Role_u_new = 'Admin':
Add DID_u_new to Reg_A.
Set Role(u_new) = '
Admin' in Auth_DB.
Else If Role_u_new = 'Issuer':
Add DID_u_new to Reg_I.
Set Role(u_new) = 'Issuer' in Auth_DB.
Else If Role_u_new = 'Holder' or 'Verifier':
Set Role(u_new) = Role_u_new in Auth_DB.
Else: Return Failure (Invalid Role).
5. Return: Return Success along with DID_u_new, PK_u_new, and SK_u_new.
3
.
3
.
2
.
Alg
o
rit
hm
2
f
o
r
is
s
ue
ce
rt
if
ica
t
e
T
h
is
alg
o
r
ith
m
d
etails
th
e
s
tep
s
in
v
o
lv
e
d
in
is
s
u
in
g
a
d
ig
ital
ac
ad
em
ic
ce
r
tific
ate
u
s
in
g
th
e
I
s
s
u
eCer
tific
ate
(
)
s
m
ar
t
co
n
tr
ac
t
f
u
n
ctio
n
.
I
t
ass
u
m
es
th
at
th
e
is
s
u
in
g
in
s
titu
tio
n
an
d
th
e
ce
r
tific
ate
h
o
ld
er
h
h
av
e
alr
ea
d
y
b
ee
n
e
n
r
o
lled
a
n
d
p
o
s
s
ess
v
alid
DI
Ds.T
h
e
I
s
s
u
eCer
tific
ate
(
)
f
u
n
ctio
n
(
Alg
o
r
ith
m
2
)
is
th
e
co
r
e
m
ec
h
an
is
m
f
o
r
c
r
ea
tin
g
a
v
e
r
if
iab
le
an
d
im
m
u
tab
le
r
ec
o
r
d
o
f
an
ac
a
d
em
ic
ce
r
tific
ate
o
n
th
e
b
lo
c
k
ch
ain
.
T
h
is
alg
o
r
ith
m
en
s
u
r
es
th
at
o
n
ly
a
u
th
o
r
ize
d
in
s
titu
tio
n
s
c
an
is
s
u
e
ce
r
tific
ates
an
d
th
at
ea
ch
ce
r
tific
ate
is
u
n
iq
u
ely
id
en
tifie
d
a
n
d
r
ec
o
r
d
ed
.
Step
1
: A
u
th
en
ticate
is
s
u
er
B
ef
o
r
e
an
y
ce
r
tific
ate
ca
n
b
e
is
s
u
ed
,
th
e
s
y
s
tem
m
u
s
t
r
ig
o
r
o
u
s
ly
au
t
h
en
ticate
th
e
r
eq
u
esti
n
g
en
tity
i
to
co
n
f
ir
m
it is
an
au
th
o
r
ized
i
s
s
u
in
g
in
s
titu
tio
n
.
T
h
is
in
v
o
lv
es two
p
r
im
ar
y
c
h
ec
k
s
:
−
DI
D
Pre
s
en
ce
in
R
eg
_
I
:
T
h
e
s
y
s
tem
f
ir
s
t
v
e
r
if
ies
th
at
t
h
e
DI
D_
i
p
r
o
v
id
ed
b
y
th
e
r
e
q
u
esti
n
g
in
s
titu
tio
n
is
p
r
esen
t
in
th
e
R
eg
_
I
(
I
s
s
u
er
R
eg
is
tr
y
)
.
T
h
is
co
n
f
ir
m
s
th
at
th
e
in
s
titu
tio
n
is
r
ec
o
g
n
ized
an
d
au
th
o
r
ized
t
o
is
s
u
e
cr
ed
en
tials
with
in
th
e
f
r
a
m
ewo
r
k
.
−
Dig
ital
Sig
n
atu
r
e
Ver
if
icatio
n
:
T
h
e
in
s
titu
tio
n
m
u
s
t
d
ig
itally
s
ig
n
th
e
r
eq
u
est_
p
a
y
lo
ad
(
wh
ich
co
n
tai
n
s
th
e
d
etails
o
f
th
e
ce
r
tific
ate
to
b
e
is
s
u
ed
)
u
s
in
g
its
SK_
i.
T
h
e
s
y
s
tem
th
en
u
s
es
i'
s
PK_
i
(
o
b
tain
ed
f
r
o
m
its
DI
D
Do
cu
m
en
t)
to
Ver
if
y
Sig
(
r
eq
u
est_
p
ay
lo
a
d
,
Sig
(
r
eq
u
est_
p
a
y
lo
ad
,
SK_
i)
,
PK_
i)
.
T
h
is
cr
y
p
to
g
r
ap
h
ic
v
e
r
if
icatio
n
p
r
o
v
es
th
at
th
e
r
eq
u
est
g
en
u
i
n
ely
o
r
ig
in
ated
f
r
o
m
i
an
d
h
as
n
o
t
b
ee
n
tam
p
er
ed
with
.
Step
2
: G
en
er
ate
ce
r
tific
ate
h
a
s
h
Evaluation Warning : The document was created with Spire.PDF for Python.
I
n
t J I
n
f
&
C
o
m
m
u
n
T
ec
h
n
o
l
I
SS
N:
2252
-
8
7
7
6
Desig
n
fr
a
mewo
r
k
fo
r
h
ig
h
er e
d
u
ca
tio
n
ce
r
tifi
ca
tes u
s
in
g
b
lo
ck
ch
a
in
tec
h
n
o
lo
g
y
(
S
a
lem
S
.
M.
K
h
a
lifa
)
1809
T
h
e
d
ig
ital
d
ata
co
n
ten
t
o
f
th
e
ce
r
tific
ate,
D_
c
(
J
SON)
,
is
p
r
o
ce
s
s
ed
b
y
th
e
SHA
2
5
6
al
g
o
r
ith
m
,
to
p
r
o
d
u
ce
a
u
n
i
q
u
e
cr
y
p
to
g
r
ap
h
ic
h
ash
h
_
c.
T
h
e
HASH(
D_
c)
f
u
n
ctio
n
tak
es
th
e
en
tire
d
ig
ital
co
n
ten
t
an
d
g
en
er
ates
a
f
ix
ed
-
s
ize
s
tr
in
g
o
f
ch
ar
ac
ter
s
.
T
h
is
h
ash
h
_
c
s
er
v
es
as
th
e
im
m
u
tab
le
d
ig
ital
f
in
g
er
p
r
in
t
o
f
th
e
ce
r
tific
ate.
E
v
en
a
m
in
o
r
ch
a
n
g
e
to
D_
c
wo
u
l
d
r
esu
lt
in
a
co
m
p
letely
d
if
f
e
r
en
t
h
_
c
.
B
y
s
to
r
in
g
o
n
ly
h
_
c
o
n
th
e
b
lo
ck
ch
ai
n
,
th
e
s
y
s
tem
en
s
u
r
es
d
ata
in
teg
r
ity
an
d
p
r
iv
a
cy
:
th
e
s
en
s
itiv
e
D_
c
r
em
ain
s
o
f
f
-
ch
ai
n
,
wh
ile
its
in
teg
r
ity
ca
n
alwa
y
s
b
e
v
er
if
ie
d
ag
ain
s
t th
e
o
n
-
ch
ain
h
ash
.
Step
3
: Ch
ec
k
f
o
r
ex
is
tin
g
ce
r
t
if
icate
Pre
v
en
tin
g
d
u
p
licates
is
e
s
s
e
n
tial
f
o
r
m
ain
tain
in
g
th
e
in
t
eg
r
ity
o
f
th
e
cr
ed
e
n
tialin
g
s
y
s
tem
an
d
av
o
id
in
g
co
n
f
u
s
io
n
o
r
p
o
ten
ti
al
ex
p
lo
its
r
elate
d
to
id
e
n
tical
ce
r
tific
ate
h
ash
es,
th
u
s
,
b
ef
o
r
e
co
m
m
itti
n
g
a
n
ew
ce
r
tific
ate
r
ec
o
r
d
to
th
e
b
l
o
ck
ch
ain
,
th
e
s
y
s
tem
q
u
er
ies
th
e
cu
r
r
en
t
s
tate
o
f
th
e
b
lo
ck
c
h
ai
n
led
g
er
(
S_
B
C
)
to
ch
ec
k
if
an
en
tr
y
with
th
e
s
am
e
h
_
c
alr
ea
d
y
ex
is
ts
.
Step
4
: Pr
ep
ar
e
led
g
er
en
tr
y
I
f
th
e
ce
r
tific
ate
is
u
n
iq
u
e,
a
n
ew
led
g
er
en
tr
y
(
n
ew_
E
n
tr
y
)
i
s
co
n
s
tr
u
cted
.
T
h
is
en
tr
y
is
a
s
tr
u
ctu
r
ed
tu
p
le
co
n
tain
in
g
h
_
c
,
DI
D_
i,
DI
D_
h
,
th
e
cu
r
r
en
t
tim
estam
p
(
T
_
c
u
r
r
en
t)
,
a
n
in
itial
r
ev
o
ca
tio
n
Statu
s
o
f
f
alse,
an
d
an
em
p
ty
r
e
v
o
ca
tio
n
R
ea
s
o
n
.
T
h
is
s
tep
ag
g
r
eg
ates
all
th
e
ess
en
tial,
im
m
u
tab
le
m
etad
at
a
th
at
will
b
e
s
to
r
ed
o
n
th
e
b
lo
ck
c
h
ain
.
T
h
e
tim
estam
p
p
r
o
v
id
es
a
v
er
if
iab
le
r
e
co
r
d
o
f
wh
e
n
th
e
ce
r
tific
ate
was
is
s
u
ed
,
an
d
th
e
in
itial f
alse r
ev
o
ca
tio
n
s
tatu
s
is
a
d
ef
au
lt th
at
ca
n
o
n
ly
b
e
ch
an
g
ed
b
y
an
au
th
o
r
ized
R
ev
o
k
eCer
tific
ate
(
)
ca
ll.
Step
5
: I
n
v
o
k
e
s
m
ar
t c
o
n
tr
ac
t
T
h
e
s
y
s
tem
th
en
in
itiates
a
tr
an
s
ac
tio
n
to
ca
ll
th
e
is
s
u
eCer
tific
ate
f
u
n
ctio
n
o
f
th
e
d
ep
lo
y
ed
C
er
tific
ateM
an
ag
er
s
m
ar
t
co
n
tr
ac
t
o
n
th
e
b
lo
ck
ch
ain
n
etwo
r
k
.
T
h
e
C
allSm
ar
tC
o
n
tr
ac
t
(
)
f
u
n
ctio
n
tr
an
s
m
its
h
_
c,
DI
D_
i,
DI
D
_
h
,
a
n
d
T
_
cu
r
r
en
t a
s
ar
g
u
m
en
ts
to
th
e
s
m
ar
t c
o
n
tr
ac
t.
Step
6
: U
p
d
ate
B
lo
ck
ch
ain
Sta
te
U
p
o
n
s
u
c
c
es
s
f
u
l
e
x
e
c
u
t
i
o
n
o
f
t
h
e
i
s
s
u
eC
e
r
ti
f
i
c
a
te
s
m
a
r
t
co
n
t
r
a
c
t
f
u
n
c
t
i
o
n
,
t
h
e
b
l
o
c
k
c
h
a
i
n
l
e
d
g
e
r
(
S
_
B
C
)
is
u
p
d
a
t
e
d
.
T
h
e
n
e
w
_
E
n
t
r
y
i
s
a
d
d
e
d
t
o
t
h
e
l
e
d
g
e
r
,
b
e
c
o
m
i
n
g
a
n
i
m
m
u
t
a
b
l
e
p
a
r
t
o
f
t
h
e
b
l
o
c
k
c
h
a
i
n
'
s
h
i
s
t
o
r
y
.
T
h
is
u
p
d
a
t
e
is
p
r
o
p
a
g
a
t
e
d
a
c
r
o
s
s
a
l
l
p
a
r
t
i
ci
p
a
t
i
n
g
n
o
d
e
s
i
n
t
h
e
n
e
tw
o
r
k
,
e
n
s
u
r
i
n
g
c
o
n
s
e
n
s
u
s
a
n
d
d
at
a
c
o
n
s
i
s
t
e
n
c
y
.
O
n
c
e
n
e
w
_
E
n
t
r
y
is
r
e
c
o
r
d
e
d
,
i
t
c
a
n
n
o
t
b
e
a
lt
e
r
e
d
o
r
r
e
m
o
v
e
d
,
p
r
o
v
i
d
i
n
g
a
p
e
r
m
a
n
e
n
t
a
n
d
v
e
r
i
f
i
a
b
l
e
r
e
c
o
r
d
o
f
t
h
e
c
e
r
t
i
f
i
c
at
e'
s
i
s
s
u
an
c
e
.
T
h
i
s
f
o
r
m
s
t
h
e
f
o
u
n
d
a
t
i
o
n
o
f
t
r
u
s
t
f
o
r
a
l
l
s
u
b
s
e
q
u
e
n
t
v
e
r
i
f
i
c
a
t
i
o
n
p
r
o
c
e
s
s
es
.
Step
7
: Retu
r
n
s
tatu
s
T
h
e
al
g
o
r
it
h
m
c
o
n
cl
u
d
es
b
y
r
e
tu
r
n
in
g
a
Su
cc
ess
s
ta
tu
s
al
o
n
g
wit
h
t
h
e
g
e
n
e
r
a
te
d
h
_
c.
I
f
a
n
y
s
tep
al
o
n
g
th
e
w
ay
f
ai
le
d
(
e
.
g
.
,
a
u
t
h
e
n
ti
ca
tio
n
f
ail
u
r
e
,
d
u
p
lic
at
e
ce
r
ti
f
i
ca
t
e
h
as
h
)
,
a
Fa
il
u
r
e
s
t
at
u
s
wo
u
l
d
b
e
r
et
u
r
n
ed
.
Alg
o
r
ith
m
2
.
Fo
r
is
s
u
e
ce
r
tific
ate
Input:
i: The issuing institution (i
∈
I).
h: The certificate holder (h
∈
H).
D_c: The digital data content of the academic certificate to be issued.
Output:
•
h_c: The cryptographic hash of the issued certificate.
•
Success or Failure status.
Steps:
1
Authenticate Iss
uer:
Verify that is an authorized issuer.
Check if DID_i is present in Reg_I.
Authenticate i's request using VerifySig(request_payload, Sig(request_payload, SK_i),
PK_i).
If authentication fails, return Failure.
2
Generate Certificate Hash:
Compute the crypt
ographic hash of the certificate data:
h_c ← HASH(D_c) (using SHA
-
256).
3
Check for Existing Certificate:
Query the blockchain ledger S_BC to ensure h_c has
not been previously issued.
If Entry(h_c) exists in S_BC, return Failure (Certificate already exists)
.
4
Prepare Ledger Entry:
Construct the new ledger entry for the certificate:
T_current ← CurrentTimestamp ()
new_Entry ← (h_c, DID_i, DID_h, T_current, false, "")
5
Invoke Smart Contract:
Call the issueCertificate function of the
CertificateManager
smart contract on the blockchain network.
6
Update Blockchain State:
Upon successful execution of the smart contract, the
blockchain ledger
S_BC
is updated with new_Entry.
7
Return:
Return Success along with
h_c
.
CallSmartContract ("Certific
ateManager", "issueCertificate",
h_c, DID_i
,
DID_h,
T_current
)
3
.
3
.
3
.
Alg
o
rit
hm
3
inte
g
ra
t
io
n
a
nd
s
ec
urit
y
A.
Cer
t
if
ica
t
e
encr
y
ptio
n a
nd
o
f
f
-
cha
in s
t
o
ra
g
e
T
h
i
s
s
t
a
g
e
is
c
r
i
ti
c
a
l
f
o
r
b
a
l
a
n
ci
n
g
d
a
t
a
p
r
i
v
a
c
y
(
R
E
Q
3
)
wi
t
h
I
m
m
u
t
a
b
i
l
i
t
y
.
I
n
a
b
l
o
c
k
c
h
a
i
n
f
r
a
m
e
w
o
r
k
,
s
t
o
r
i
n
g
l
a
r
g
e
f
i
l
es
l
i
k
e
P
DFs
o
r
f
u
l
l
J
S
O
N
o
b
j
e
ct
s
d
i
r
e
ct
l
y
o
n
t
h
e
l
e
d
g
e
r
i
s
i
n
e
f
f
i
c
i
e
n
t
a
n
d
e
x
p
e
n
s
i
v
e
.
I
n
s
t
e
a
d
,
Evaluation Warning : The document was created with Spire.PDF for Python.