In this second part Kristof V. explained an actual proof of concept developed in the Belgian government: a (permission) blockchain solution for medical prescriptions. Link to the event follow-up page: https://www.meetup.com/Brussels-Legal-Hackers/messages/boards/thread/50920056 Legal hackers: https://www.meetup.com/Brussels-Legal-Hackers Similar presentation (in Dutch): https://www.youtube.com/watch?v=oqRoBJ4gIHE&list=PLkOT_gtPps66Tr-Hs15scP1gw-hIftDeE&index=7

1. ²
1
Medical Prescriptions
on a Public Blockchain
Kristof Verslype, Smals Research20 June 2017

2. Recap: Smart Contracts
2
Contract Auction{
function bid(){…}
function end(){…}
HighestBid: €
HighestBidder:
Beneficiary: Charlie
}
bid(...), 20€
end(...)
bid(...), 10€
20€
02010
Bob
Alice
Charlie
Alice
10€
Bob
bidEvent: 10€
bidEvent: 10€
bidEvent: 20€
bidEvent: 20€
Dave
Contract code execution distributed
Money can be temporarily blocked by contract
Function calls in transactions on blockchain

3. Processing Medical Prescriptions
3
Doctor Pharmacist
€ €
€
€
Mutuality
Patient
Tarification
office
Processing prescriptions s.t.
reimbursement possible
Real-time analysis RIZIV/INAMI
Traditional money transfer
Data flow
Physical delivery

4. Processing Medical Prescriptions
4
Doctor
€ €
€
€
Mutuality
Patient
Tarification
office
Complex information
flowsTraditional money transfer
Data flow
Physical delivery
Pharmacist

5. Processing Medical Prescriptions
5
Doctor Pharmacist
Mutuality
Patient
Tarification
office
All other communication with blockchain
Privacy & confidentiality enterprise data guaranteed
Traditional money transfer
Show on smartphone
Physical delivery

6. 7a2
3b
3a
4
5 7b
8 9 10a
10b
issue() fill() confirm()insure() assign()
Contract function call
Event observation
Direct communication
Doctor Patient Pharmacist
Tar. officeMutuality
Prescription
Medicine
Valid from
Patient
Tarification office
Mutuality
Pharmacist
Doctor
Delivered
Id
Reduced fee?
Prescription
Medicine
Valid from
Patient
Tarification office
Mutuality
Pharmacist
Doctor
Delivered
Id
Reduced fee?
Prescription
Medicine
Valid from
Patient
Tarification office
Mutuality
Pharmacist
Doctor
Delivered
Id
Reduced fee?
6a
1 6b
function() Contract function
The Smart Contract
6

7. Privacy with permanent pseudonyms
7
Prescription 158
Valid from
Valid from
Patient
Tarification office
Mutuality
Pharmacist
Doctor
Reduced fee?
Delivered
Prescription 577
Medicine
Valid from
Patient
Tarification office
Mutuality
Pharmacist
Doctor
Reduced fee?
Delivered
Prescription 804
Medicine
Valid from
Patient
Tarification office
Mutuality
Pharmacist
Doctor
Reduced fee?
Delivered
Permanent pseudonyms offer insufficient protection of 1) citizen’s
privacy and 2) confidentiality of enterprise data
Id Id Id

8. 8
One-Time Pseudonyms
Charlie
Bob
Alice
Blockchain network
Link
Link
Link
Link
8

9. Different Views
9
One-time patient pseudonyms on the blockchain
Rest of the world
Similar for doctors, pharmacists, mutualities and tarification offices

10. Link Attack 1
10
Doctor: 02/04/17, 21h30 (A)
Pharmacist: 28/04/17, 20h45 (B)
A B
Combining info real world & blockchain can leak sensitive data
Attacker knows patient identity & observes him/her physically

11. 11
Doctor: 02/04/17, 21h30 (A)
Pharmacist: 28/04/17, 20h45 (B)
A B
Prescription
Medicine
Valid from
Patient
Tarification office
Mutuality
Pharmacist
Doctor
Delivered
Id
Reduced fee?
→ Encryption of sensitive data in
blockchain/smart contract
Difficult attack, but one success
enough to torpedo project
Link Attack 1
Combining info real world & blockchain can leak sensitive data
Attacker knows patient identity & observes him/her physically

12. Different Views
Prescription
Pantoprazol 20mg
True
…
Prescription
???
???
…
Rest of the world
My
Prescription
Pantoprazol 20mg
???
…
My
…
=> fine grained access control with encryption 12

13. Interface
13
Ontvang
Consumeer
Mijn voorschriften
Oproep functie in contract
Observatie event

14. 14
Toon QR-code
aan Arts
Interface
Nieuwe code
Arts
Medicijn
Geldig vanaf [Optioneel]
Uitgeven Voorschrift
Scan patient QR-code
Geef voorschrift uit
Etanercept 1mg

15. Interface
15
Ontvang
Consumeer
Nieuw Voorschrift
Etanercept 1mg
Mijn voorschriften

16. Interface
16
Ontvang
Consumeer
Mijn voorschriften

17. 17
Pantoprazol 20mg
Etanercept 1mg
Adalimumab 5mg
Adalimumab 5mg
Interface
Mijn voorschriften

18. 18
Adalimumab 5mg
<< Front camera active >>
Toon QR-code
aan apotheker
Interface - Dispense
Apotheker
OK

19. 19
Interface - Dispense
Apotheker
Adalimumab 5mg
Pantoprazol 20mg
Process
RefundDrug Processed
15,30€
9,13€

20. 20
Pantoprazol 20mg
Etanercept 1mg
Adalimumab 5mg
Adalimumab 5mg
Interface - Dispense
Mijn voorschriften

21. The bigger picture
Een Blockchain Ecosysteem
21
Arts
Mutualiteit
Werkgever Hospitaal
Eén medische consultatie kan een hele set acties in gang zetten,
met blockchain als centrale as.
Voorschrift
Bewijs verstrekte hulp
Bewijs van arbeidsongeschiktheid
Doorverwijzing naar hospitaal
Rekening hospitaal voor mutualiteit
…

22. Storage for 1 Year (Estimates)
22
±270GB ±270GB
Mutuality
±270GB
Tar. office
Only RIZIV/INAMI, mutualities and tarification
offices need full copy of blockchain.
If prescriptions max. 1 year valid, blockchain can
be truncated s.t. old transactions are ‘forgotten’
Optimizations possible

23. Key Management
Good protection of keys required
Link
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Link
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Link
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Link
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Link
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LinkLink LinkLink
→Link
→
Link
→
Link
→
Link
Link
Link
Link
Link
Link
23

24. Prescription Blockchain Network
24
Full node
Frequent light node
Occasional light node
Block creation
By RIZIV/INAMI, mutualities, and/or tarification offices.
Ex. Signatures by 5 of 7 mutualities

25. Evaluation
25
Privacy & confidentiality
- Strong guarantees
- No central, all-knowing, all-mighty big brother
- RIZIV/INAMI analyses in real-time while respecting privacy
Communication
- No complex information flows
- All information everywhere (almost) in real-time
Challenges
- More complex key management
- Higher requirements for storage and communication
Higher availability
=> interesting blockchain case / experience

26. 26
Smals www.smals.be
@Smals_ICT
www.smalsresearch.be
@SmalsResearch
Kristof Verslype
@KristofVerslype
02 787 53 76
kristof.verslype@smals.be
be.linkedin.com/in/verslype