Privacy-Preserving IoT Data Aggregation Based on Blockchain and Homomorphic Encryption

. 2021 Apr 2;21(7):2452. doi: 10.3390/s21072452

Algorithm 1 Privacy Attribute Matching

Input: Terms_of_Service

T o S

Output: Privacy_Policy

P P o l i c y

1:
$P R u l e \leftarrow ⌀$ ; $P P o l i c y \leftarrow ⌀$
2:
$D C a t e g o r y = T o S . r e q u e s t e d D a t a . h a s D a t a C a t e g o r y$
3:
$P R u l e = D C a t e g o r y . h a s P r i v a c y R u l e$
4:
$i n t e n d e d P A$ = {Purpose, Operation, Disclosure, Retention, Condition}
5:
for each $i p a$ in $i n t e n d e d P A$ do
6:
switch ( $i p a$ )
7:
case Purpose:
8:
if ( $T o S . r e q u e s t e d P u r p o s e \notin P r o h i b i t e d P u r p o s e s$ and $T o S . r e q u e s t e d P u r p o s e \in A l l o w e d P u r p o s e s$ ) then
9:
$P P o l i c y . e f f P u r p = T o S . r e q u e s t e d P u r p o s e$
10:
else
11:
return $P P o l i c y$
12:
end if
13:
case Operation:
14:
if ( $T o S . r e q u e s t e d O p e r a t i o n \notin P r o h i b i t e d O p e r a t i o n s$ and $T o S . r e q u e s t e d O p e r a t i o n \in A l l o w e d O p e r a t i o n s$ ) then
15:
$P P o l i c y . e f f O p e = T o S . r e q u e s t e d O p e r a t i o n$
16:
else
17:
return $P P o l i c y$
18:
end if
19:
case Disclosure:
20:
if ( $T o S . r e q u e s t e d D i s c l o s u r e \notin P r o h i b i t e d D i s c l o s u r e s$ and $T o S . r e q u e s t e d D i s c l o s u r e \in A l l o w e d D i s c l o s u r e s$ ) then
21:
$P P o l i c y . e f f D i s c = T o S . r e q u e s t e d D i s c l o s u r e$
22:
else
23:
return $P P o l i c y$
24:
end if
25:
case Retention:
26:
if ( $T o S . r e q u e s t e d R e t e n t i o n < P R u l e . r e t e n t i o n$ ) then
27:
$P P o l i c y . e f f R e t = T o S . r e q u e s t e d R e t e n t i o n$
28:
else
29:
return $P P o l i c y$
30:
end if
31:
case Condition:
32:
if ( $P R u l e . i c o n d . a l l o w e d R o l e$ == $T o S . h a s I n i t i a t o r . h a s R o l e$ ) then
33:
$P P o l i c y . e f f C o n d i t i o n = P R u l e . i c o n d$
34:
else
35:
return $P P o l i c y$
36:
end if
37:
end switch
38:
end for
39:
$P P o l i c y . h a s R e q u e s t e d O u t p u t$ = $o u t p u t$
40:
$P P o l i c y . h a s A c c e s s D e c i s i o n$ = $P e r m i t$
41:
$P P o l i c y . h a s P r i v a c y O b l i g a t i o n = P R u l e . h a s P r i v a c y R u l e O b l i g a t i o n$
42:
return $P P o l i c y$