楊皓丞、許育銘、黃文彥
唐浩、薛佳哲
school
database
(ID, time, building)
(ID, time, building)
(ID, time, building)
.
.
.
personnel
send data
record
Current scheme
find patient's footprints
and contacts
confirmed
diagnosis
school
database
(ID, time, building)
(ID, time, building)
(ID, time, building)
.
.
.
personnel
send data
record
Current scheme - possible attacks
personnel
visitor
fake identity
school
external
attacker
read
database
find patient's footprints
and contacts
confirmed
diagnosis
school
database
(time, building, \(\sigma\))
(time, building, \(\sigma\))
(time, building, \(\sigma\))
.
.
.
personnel
authenticate
record
Proposed scheme
find patient's footprints
and contacts
verify
CDC
send data
confirmed
diagnosis
school
database
(time, building, \(\sigma\))
.
.
.
personnel
authenticate
record
Proposed scheme - threat model & security properties
find patient's footprints
and contacts
verify
CDC
send data
confirmed
diagnosis
school
external
attacker
read
database
Anonymity
Unlinkability
Traceability
personnel
visitor
fake identity
Authentication
school
personnel
1. send today's revocation list
CDC
2. record the revocation list
Everyday morning
Note: even with the revocation
functionality, the group signature is anonymous and backward unlinkable
database
personnel
1. generate a signature of the message containing building and timestamp
3. verify the signature is valid and the signer not revoked
When a personnel enters a building
2. send the message
with signature
4. allow entrance and record to database
school
database
CDC
personnel
1. notify school of a confirmed diagnosis
When there is a confirmed diagnosis in school
2. send records of
past 14 days to CDC
3. open the signers' identity to find patient footprint and contacts
school
database
CDC
4. revoke the patient and contacts for the next 14 days
5. send patient footprint
and contacts
SGS | VLR | |
---|---|---|
keygen (30000 users) | 58.539s | 82.342s |
authentication time (no revoked personnel) |
0.898s | 1.535s |
authentication time (1000 revoked personnel) |
X | 2.585s |
open (total 3000 records, 900 quarantine records) | 12.818s | 1945s (32 mins) |