![Page 1: Prof. Aviv Zohar - The Federmann Cyber Security Center · 2019. 12. 31. · Prof. Aviv Zohar The Hebrew University of Jerusalem & QEDIT. About me ... (without revealing) Outcomes:](https://reader033.vdocuments.mx/reader033/viewer/2022061002/60b0ec1ac27512584b7d2b6d/html5/thumbnails/1.jpg)
Prof. Aviv Zohar
The Hebrew University of Jerusalem & QEDIT
![Page 2: Prof. Aviv Zohar - The Federmann Cyber Security Center · 2019. 12. 31. · Prof. Aviv Zohar The Hebrew University of Jerusalem & QEDIT. About me ... (without revealing) Outcomes:](https://reader033.vdocuments.mx/reader033/viewer/2022061002/60b0ec1ac27512584b7d2b6d/html5/thumbnails/2.jpg)
About me
Computer Scientist at Hebrew U.
Researching cryptocurrencies (Security, scalability, economic incentives etc.) since 2011
Co-founder & Chief scientist at QEDIT a company creating “enhanced privacy”
solutions for enterprise market.
![Page 3: Prof. Aviv Zohar - The Federmann Cyber Security Center · 2019. 12. 31. · Prof. Aviv Zohar The Hebrew University of Jerusalem & QEDIT. About me ... (without revealing) Outcomes:](https://reader033.vdocuments.mx/reader033/viewer/2022061002/60b0ec1ac27512584b7d2b6d/html5/thumbnails/3.jpg)
Blockchain systems
Reliably duplicate data
between many computers
Repeat the same
computation and reach the
same conclusions
For Bitcoin: data is a ledger
containing all transactions
![Page 4: Prof. Aviv Zohar - The Federmann Cyber Security Center · 2019. 12. 31. · Prof. Aviv Zohar The Hebrew University of Jerusalem & QEDIT. About me ... (without revealing) Outcomes:](https://reader033.vdocuments.mx/reader033/viewer/2022061002/60b0ec1ac27512584b7d2b6d/html5/thumbnails/4.jpg)
Generated using oxt.me
100BTC of paymets to Locky aggregated
into an exchange
(payments 0.5,1,2,3,7 BTC collected into
two 50 BTC transactions)
Bitcoin isn’t Private
![Page 5: Prof. Aviv Zohar - The Federmann Cyber Security Center · 2019. 12. 31. · Prof. Aviv Zohar The Hebrew University of Jerusalem & QEDIT. About me ... (without revealing) Outcomes:](https://reader033.vdocuments.mx/reader033/viewer/2022061002/60b0ec1ac27512584b7d2b6d/html5/thumbnails/5.jpg)
Generated using oxt.me
Following change
addresses leads
to more…
![Page 6: Prof. Aviv Zohar - The Federmann Cyber Security Center · 2019. 12. 31. · Prof. Aviv Zohar The Hebrew University of Jerusalem & QEDIT. About me ... (without revealing) Outcomes:](https://reader033.vdocuments.mx/reader033/viewer/2022061002/60b0ec1ac27512584b7d2b6d/html5/thumbnails/6.jpg)
Generated using oxt.me
And more…
This is activity over ~1month
Yielding ~2-3 M USD.
![Page 7: Prof. Aviv Zohar - The Federmann Cyber Security Center · 2019. 12. 31. · Prof. Aviv Zohar The Hebrew University of Jerusalem & QEDIT. About me ... (without revealing) Outcomes:](https://reader033.vdocuments.mx/reader033/viewer/2022061002/60b0ec1ac27512584b7d2b6d/html5/thumbnails/7.jpg)
Generated using oxt.me
Transactions laundering
money in a mixer.
![Page 8: Prof. Aviv Zohar - The Federmann Cyber Security Center · 2019. 12. 31. · Prof. Aviv Zohar The Hebrew University of Jerusalem & QEDIT. About me ... (without revealing) Outcomes:](https://reader033.vdocuments.mx/reader033/viewer/2022061002/60b0ec1ac27512584b7d2b6d/html5/thumbnails/8.jpg)
![Page 9: Prof. Aviv Zohar - The Federmann Cyber Security Center · 2019. 12. 31. · Prof. Aviv Zohar The Hebrew University of Jerusalem & QEDIT. About me ... (without revealing) Outcomes:](https://reader033.vdocuments.mx/reader033/viewer/2022061002/60b0ec1ac27512584b7d2b6d/html5/thumbnails/9.jpg)
9
I know the solution.And I can prove it!
… but without showing you the answer
![Page 10: Prof. Aviv Zohar - The Federmann Cyber Security Center · 2019. 12. 31. · Prof. Aviv Zohar The Hebrew University of Jerusalem & QEDIT. About me ... (without revealing) Outcomes:](https://reader033.vdocuments.mx/reader033/viewer/2022061002/60b0ec1ac27512584b7d2b6d/html5/thumbnails/10.jpg)
10
![Page 11: Prof. Aviv Zohar - The Federmann Cyber Security Center · 2019. 12. 31. · Prof. Aviv Zohar The Hebrew University of Jerusalem & QEDIT. About me ... (without revealing) Outcomes:](https://reader033.vdocuments.mx/reader033/viewer/2022061002/60b0ec1ac27512584b7d2b6d/html5/thumbnails/11.jpg)
11
7
5 3 4
8 6
4 6 7 5
9 1 4
5 1 2 6
6 8 9
5 9 1 2
6 7
6 5 1
Pick what to test:Rows, Columns, or Boxes
Rows please.
<<rolls some dice>>
![Page 12: Prof. Aviv Zohar - The Federmann Cyber Security Center · 2019. 12. 31. · Prof. Aviv Zohar The Hebrew University of Jerusalem & QEDIT. About me ... (without revealing) Outcomes:](https://reader033.vdocuments.mx/reader033/viewer/2022061002/60b0ec1ac27512584b7d2b6d/html5/thumbnails/12.jpg)
12
7
5 3 4
8 6
4 6 7 5
9 1 4
5 1 2 6
6 8 9
5 9 1 2
6 7
6 5 1
![Page 13: Prof. Aviv Zohar - The Federmann Cyber Security Center · 2019. 12. 31. · Prof. Aviv Zohar The Hebrew University of Jerusalem & QEDIT. About me ... (without revealing) Outcomes:](https://reader033.vdocuments.mx/reader033/viewer/2022061002/60b0ec1ac27512584b7d2b6d/html5/thumbnails/13.jpg)
13
123456789
<<Checks each bag>><<Each contains digits 1-9>>
Okay.
You were lucky.Do that again.
![Page 14: Prof. Aviv Zohar - The Federmann Cyber Security Center · 2019. 12. 31. · Prof. Aviv Zohar The Hebrew University of Jerusalem & QEDIT. About me ... (without revealing) Outcomes:](https://reader033.vdocuments.mx/reader033/viewer/2022061002/60b0ec1ac27512584b7d2b6d/html5/thumbnails/14.jpg)
Completeness:
If Peter knows the solution, he can always pass the test.
Soundness:
If Peter tries to cheat: there is at least one row / column / box that is incorrect. Veronica will catch him with probability ≥
1
3
Repeating the procedure N times means he cheats with
probability ≤2
3
𝑁
Zero Knowledge:
Veronica learns nothing about the solution, except that it’s correct.
14
![Page 15: Prof. Aviv Zohar - The Federmann Cyber Security Center · 2019. 12. 31. · Prof. Aviv Zohar The Hebrew University of Jerusalem & QEDIT. About me ... (without revealing) Outcomes:](https://reader033.vdocuments.mx/reader033/viewer/2022061002/60b0ec1ac27512584b7d2b6d/html5/thumbnails/15.jpg)
Alice
owns 1
coin
Advanced privacy layers
Zero knowledge proofs applied to blockchains: (ZeroCash [Ben Sasson et. al])
encrypted
Bob
owns 1
coin
To
transfer:
Prove
(in Zero Knowledge):
amount received by Bob
= amount Alice owned
(without revealing)
Outcomes:
1. Cannot see amounts
2. Cannot link payments
But, transactions are still
validated.
![Page 16: Prof. Aviv Zohar - The Federmann Cyber Security Center · 2019. 12. 31. · Prof. Aviv Zohar The Hebrew University of Jerusalem & QEDIT. About me ... (without revealing) Outcomes:](https://reader033.vdocuments.mx/reader033/viewer/2022061002/60b0ec1ac27512584b7d2b6d/html5/thumbnails/16.jpg)
𝑎𝑚𝑜𝑢𝑛𝑡2, 𝑝𝑢𝑏𝐴𝑑𝑑𝑟2
• c3 = 𝑐𝑜𝑚𝑚𝑖𝑡(𝑎𝑚𝑜𝑢𝑛𝑡3, 𝑝𝑢𝑏𝐴𝑑𝑑𝑟3)• ∃ records c1, c2 on the blockchain• c1 = 𝑐𝑜𝑚𝑚𝑖𝑡 𝑎𝑚𝑜𝑢𝑛𝑡1, 𝑝𝑢𝑏𝐴𝑑𝑑𝑟1• c2 = 𝑐𝑜𝑚𝑚𝑖𝑡 𝑎𝑚𝑜𝑢𝑛𝑡2, 𝑝𝑢𝑏𝐴𝑑𝑑𝑟2• a𝑚𝑜𝑢𝑛𝑡3 = 𝑎𝑚𝑜𝑢𝑛𝑡1 + 𝑎𝑚𝑜𝑢𝑛𝑡2• a𝑚𝑜𝑢𝑛𝑡3 ≥ 0• ∃ 𝑠𝑒𝑐𝑟𝑒𝑡𝐾𝑒𝑦1, 𝑠𝑒𝑐𝑟𝑒𝑡𝐾𝑒𝑦2 that match
𝑝𝑢𝑏𝐴𝑑𝑑𝑟1, 𝑝𝑢𝑏𝐴𝑑𝑑𝑟2 (and I know them)
𝑎𝑚𝑜𝑢𝑛𝑡1, 𝑝𝑢𝑏𝐴𝑑𝑑𝑟1
𝑎𝑚𝑜𝑢𝑛𝑡3, 𝑝𝑢𝑏𝐴𝑑𝑑𝑟3
𝑐3
𝑐2
𝑐1
𝜋
![Page 17: Prof. Aviv Zohar - The Federmann Cyber Security Center · 2019. 12. 31. · Prof. Aviv Zohar The Hebrew University of Jerusalem & QEDIT. About me ... (without revealing) Outcomes:](https://reader033.vdocuments.mx/reader033/viewer/2022061002/60b0ec1ac27512584b7d2b6d/html5/thumbnails/17.jpg)
Blockchain dreams
& privacy problems
![Page 18: Prof. Aviv Zohar - The Federmann Cyber Security Center · 2019. 12. 31. · Prof. Aviv Zohar The Hebrew University of Jerusalem & QEDIT. About me ... (without revealing) Outcomes:](https://reader033.vdocuments.mx/reader033/viewer/2022061002/60b0ec1ac27512584b7d2b6d/html5/thumbnails/18.jpg)
![Page 19: Prof. Aviv Zohar - The Federmann Cyber Security Center · 2019. 12. 31. · Prof. Aviv Zohar The Hebrew University of Jerusalem & QEDIT. About me ... (without revealing) Outcomes:](https://reader033.vdocuments.mx/reader033/viewer/2022061002/60b0ec1ac27512584b7d2b6d/html5/thumbnails/19.jpg)
![Page 20: Prof. Aviv Zohar - The Federmann Cyber Security Center · 2019. 12. 31. · Prof. Aviv Zohar The Hebrew University of Jerusalem & QEDIT. About me ... (without revealing) Outcomes:](https://reader033.vdocuments.mx/reader033/viewer/2022061002/60b0ec1ac27512584b7d2b6d/html5/thumbnails/20.jpg)
![Page 21: Prof. Aviv Zohar - The Federmann Cyber Security Center · 2019. 12. 31. · Prof. Aviv Zohar The Hebrew University of Jerusalem & QEDIT. About me ... (without revealing) Outcomes:](https://reader033.vdocuments.mx/reader033/viewer/2022061002/60b0ec1ac27512584b7d2b6d/html5/thumbnails/21.jpg)
![Page 22: Prof. Aviv Zohar - The Federmann Cyber Security Center · 2019. 12. 31. · Prof. Aviv Zohar The Hebrew University of Jerusalem & QEDIT. About me ... (without revealing) Outcomes:](https://reader033.vdocuments.mx/reader033/viewer/2022061002/60b0ec1ac27512584b7d2b6d/html5/thumbnails/22.jpg)
The account I am sending to is private,
but it’s not blacklisted
Transaction is below 10K or was
reported to regulator
I paid taxes on my income (but don’t
reveal income amounts)
![Page 23: Prof. Aviv Zohar - The Federmann Cyber Security Center · 2019. 12. 31. · Prof. Aviv Zohar The Hebrew University of Jerusalem & QEDIT. About me ... (without revealing) Outcomes:](https://reader033.vdocuments.mx/reader033/viewer/2022061002/60b0ec1ac27512584b7d2b6d/html5/thumbnails/23.jpg)
Many more uses
KYC
I’m an accredited investor
Insurance
I properly maintain my car
I get checked by the doctor periodically
Supply Chain
My supplier is on time so I too will supply on
time
![Page 24: Prof. Aviv Zohar - The Federmann Cyber Security Center · 2019. 12. 31. · Prof. Aviv Zohar The Hebrew University of Jerusalem & QEDIT. About me ... (without revealing) Outcomes:](https://reader033.vdocuments.mx/reader033/viewer/2022061002/60b0ec1ac27512584b7d2b6d/html5/thumbnails/24.jpg)
For more information:
Summary:
Zero knowledge proofs:
• Enabling a new kind of information economy.
Data stays in silo, proofs move around.
• Also extreme privacy in cryptocurrencies
• Can regulate / tax without seeing all data?