ZK based Health Records/Data Sharing Marketplace

Built on top of the following tech stack

ZK based Health Records/Data Sharing Marketplace is built on top of the following tech stack:

• Noir (for ZK Circuit)
• zkVerify (for ZK Attestation)
• EDU Chain (for deploying smart contracts)
• Solidity / Foundry (for smart contract development)
• Next.js / React (for front-end)

Overview

In the drug descovery space, which is one of space in DeSci, there are problems for the following actors respectively:

• For a Health Data Provider (i.e. patient, wearable device holder like Apple Watch holder), there is negative situations that their unnecessary sensitive informations may also be leaked when they share their health records/data with Medical Researchers. Also, there is lack of incentive to share their health records/data with Medical Researchers.
• For a Medical Researcher, there is lack of access to large amount of the health records/data, which the data integrity is kept, to be analyzed for developing new drugs. Also, there is lack of transparent marketplace of them. These are one of cause of that makes the speed (pace) of new drug discovery slower.

The ZK (Zero-Knowledge) based Health Records/Data Sharing Marketplace, which is built on top of Noir and zkVerify, can resolved the problems above by applying ZK (Zero-Knowledge) cryptographic techniques and smart contract/blockchain in order to securely share (buy/sell) sensitive health records/data while maintaining strong privacy protections. This allow for more collaborative and open medical research (in DeSci space) without compromising individual privacy.

In the Marketplace where buy/sell a Health records/data, there are the following 2 actors:

• Seller: Health Data Provider (i.e. patient, wearable device holder like Apple Watch holder)
• Buyer: Medical Researcher (who want to analze Health records/data for developing new drugs)

The advantage for a Health Data Provider (Seller) is that:

• A Health Data Provider can share (sell) their health data without sensitive data (i.e. Age, Name).

  • NOTE: In the ZK circuit in Noir of this project (./circuits/src/main.nr), whether or not the age of a Health Data Provider is above 18 would be validated.

• A Health Data Provider can choose which data they want to share (as the "Selective Disclosure" feature)

  • NOTE: In the ZK circuit in Noir of this project (./circuits/src/main.nr), the "Selective Disclosure" feature can be seen.

• In exchange for sharing (selling) their health records/data, a Health Data Provider can earn the rewards (fees) as a financial incentive, which is paid by a Medical Researcher when the Medical Researcher buy their health data.

The advantage for a Medical Researcher (Buyer) is that:

• A Medical Researcher can securely collect (buy) a health records/data that the data integrity is kept by ZK Proof, which is generated in Noir and attested by zkVerify.

• A Medical Researcher can securely collect (buy) a health records/data from the transparent market thanks to transacting on the smart contract based marketplace.

Archtecture and Userflow

• Archtecture and Userflow: https://github.com/masaun/ZK-health-records-sharing-marketplace/tree/main/doc/diagrams
  

• NOTE:

  • The actual functionality of the ZK based Health Records/Data Sharing Marketplace would mainly be implemented in the HealthDataSharingExecutor contract (HealthDataSharingExecutor.sol).

  • For the moment, a Health Data Provider would input their Health records/data (input data) via the Prover.toml (./circuits/src/Prover.toml) to generate Noir's UltraPlonk Proof and zkVerify's UltraPlonk Proof.

  • In the future, these input data should be inputted via UI.

DEMO Video

Basic information of DEMO Video

• DEMO Video link: https://youtu.be/itPbMRt03VM

• In the DEMO Video above, there are 2 pages:

  • The page for a Health Data Provider (URL: http://localhost:3000)
  • The other page for a Medical Researcher (URL: http://localhost:3000/medicalResearcherPage)

• Both pages can work - after locally running the frontend app in the ./app directory by the npm run dev command.

Description of DEMO Video

Describe the each section in the DEMO Video (and its time in the DEMO Video):

• Time 0.01~). Explain ZK circuit in Noir.

  • Selective Disclosure by storing a given input data into the RevealedData struct and returning it as a public input value.
  • Writing the input data (Health Records/Data) in the Prover.toml.

• Time 1:32~).

  • Generating a ZK Proof of the input data (Health Records/Data) in Noir. (The detail of this process can be seen in the "ZK circuit - Generate (Prove) an Ultraplonk proof in Noir" paragraph)

• Time 2.15~).

  • Convert an original Ultraplonk proof in Noir to an Ultraplonk proof in zkVerify version (by using UltraPlonk zk-SNARK Verifier powered by zkVerify) (The detail of this process can be seen here)

• Time 4:24~).

  • Run the frontend (UI) locally by running npm run dev command and then opening a web browser with http://localhost:3000 (which is the "Page for Health Data Provider").

• Time 4:40~).

  • On the page for Health Data Provider, connecting both wallet (Polkadot and EVM) as a Health Data Provider.
  • Then, the Health Data Provider would submit a Health Data Proof to the zkVerify Network on Polkadot through the HealthDataSharingExecutor contract (submitHealthData() function).
    • At this point, the Health Data Provider would sign and send the TX (transaction) of submitting a proof on Polkadot wallet (i.e. Talisman).
    • At this point, the proof data of the Ultraplonk proof in zkVerify would be loaded and submitted as the Health Data Proof.

• Time 5:36~).

  • On the page for Health Data Provider, the TX result of the zkVerify Network and would be returned and shown with the following data.
    • TX hash on the zkVerify Network (This TX hash can be confirm by searching on the zkVerify Block Explorer)
    • Proof Type: UltraPlonk (zk proof)
    • Attestation ID: 44354

• Time 7:36~).

  • On the page for Health Data Provider, other following attestation informations, which are generated with the Attestation ID on zkVerify Network, would be shown.
    • Merkle Root
    • Merkle Proof
    • Number of Leaves
    • Leaf Index
    • Leaf Digest

• Time 7:42~).

  • Then, the Health Data Provider would submit the Health Data Proof /w Attestation ID and so on to EDU Chain.
    • At this point, the Health Data Provider would sign and send the TX (transaction) of submitting a proof on EVM wallet (i.e. MetaMask).
    • By submitting the Health Data Proof /w Attestation ID and so on to EDU Chain, these ZK Proof Data (Proof, Public Input) and its attestation informations (i.e. Attestation ID, Leaf Digest, Merkle Proof) would be associated and saved on EDU Chain.
    • This TX hash on EDU Chain can be searched on the EDU Chain Block Explorer.

• Time 11:03~).

  • A Medical Researcher, who is a buyer of the health records/data, would open the "Page for Medical Researcher" (http://localhost:3000/medicalResearcherPage) and connect their EVM Wallet.
  • A Medical Researcher would check how much $EDU (NativeToken in EDU Chain) balance the Medical Researcher's EVM wallet hold by clicking the "Get $EDU balance of account" button.

• Time 11:37~).

  • Check which Attestation IDs of health records/data is buyable by clicking the "Get Attestation IDs of Buyable Health Data" button.
  • Since all Attestation IDs of health records/data, which is shown on the page (UI) for Medical Researcher, would be attested by zkVerify, a Medical Researcher can securely choose any Attestation ID of health records/data-shown on the page (UI) for Medical Researcher.

• Time 12:15~).

  • A Medical Researcher would buy an Attestation ID of the health records/data by specifying the Attestation ID in the input field and then clicking the "Get Attestation IDs of Buyable Health Data" button.

    • NOTE: In this demo, a medical researcher specify Attestation ID = 44667) and clicking the "Buy Health Data-attested in $EDU" button.
    • Since the price per a health records/data would be 0.00001 $EDU, 0.00001 $EDU would be transferred to the Health Data Provider (Seller) as the reward payment from the Medical Researcher (Buyer) through the HealthDataSharingExecutor contract (buyHealthData() function) on EDU Chain during the Medical Researcher's TX for buying a health records/data.

  • This TX hash on EDU Chain can been searched on the EDU Chain Block Explorer.

• Time 14:40~).

  • Once a Medical Researcher would be successful to buy the Health Data, the Medical Researcher would push the "Show a Health Data-bought in decoded-values button on the page for a Medical Researcher:
    • If you select that the revealed data (i.e. revealedName) is false for a certain item (i.e, name) when you write the input data (Health Records/Data) in the Prover.toml in the process of "ZK circuit - Generate (Prove) an Ultraplonk proof in Noir", "Not Revealed" would be shown for the item on UI.
      • In this DEMO Video, the revealedName and revealedAge was specified as false when inputing data in the Prover.toml to generate a ZK Proof in Noir. Hence, the name and age would be shown as "Not Revealed".
        • This means that this Health Data Provider could share (sell) their health records/data without revealing their name and age.
        • On the other hand, thanks to the logic-implemented in ZK circuit in Noir (./circuits/src/main.nr), whether or not the Health Data Provider would be the age of above 18 could be validated.

Limitation of DEMO Video

• Input data (Health records/data) must be inputted via the Prover.toml (./circuits/src/Prover.toml) to generate Noir's UltraPlonk Proof and zkVerify's UltraPlonk Proof.
  • In the future, these input data should be inputted via UI.

Deployed-smart contracts on EDU Chain (testnet)

Contract Name	Descripttion	Deployed-contract addresses on EDU Chain (testnet)
ZkVerifyAttestation	zkVerify ZkAttestation Contract on EDU Chain	0x147AD899D1773f5De5e064C33088b58c7acb7acf
UltraVerifier	The UltraPlonk Verifer contract (./circuits/target/contract.sol), which is generated based on ZK circuit in Noir (./circuits/src/main.nr). FYI: To generated this contract, the way of the Noir's Solidity Verifier generation was used.	0x71F3108Be6F52D59fdc220C2aFd21B3721Bf5fb7
HealthDataSharingVerifier	The smart contract that the validation is implemented for the UltraVerifier contract, which is generated by Noir's Solidity Verifier generation	0x23C6269f0807bFc14ab91A7d32Ad9b643B96cA1A
HealthDataSharingExecutor	The smart contract that works as the ZK based Health Records/Data Sharing Marketplace	0x097eB4757edba7D2c398411C07091A5Ac8ce9FEe

NOTE: Basically, the HealthDataSharingExecutor contract would work as the Health Records/Data Sharing Marketplace.

Future integration/implementation ideas

• NoirJS integration:

  • To enable a Health Data Provider to input data (their health records/data) from UI/frontend. (NOTE: Instead, for the moment, a Health Data Provider would input data through the ./circuits/Prover.toml. This way is not good from UX perspective)

• World ID integration:

  • To prevent malicious Health Data Provider from spamming (submitting a lot of meaningless health records/data).

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Installations of the ZK based Health Records/Data Sharing Marketplace

Installation - Smart contract

• Install libraries (NOTE: Before this installation, all folders should be removed under the ./lib directory)

forge install OpenZeppelin/openzeppelin-contracts
forge install 0xnonso/foundry-noir-helper

Installation - UltraPlonk zk-SNARK Verifier powered by zkVerify

• NOTE: The original repo of the ultraplonk_verifier can be seen here: https://github.com/zkVerify/ultraplonk_verifier

• 1/ Move to the ./circuits/zkVerify/ultraplonk_verifier directory:

cd circuits/zkVerify/ultraplonk_verifier

• 2/ Install the ultraplonk_verifier (v0.3.0) \

cargo install --features bins --path .

(NOTE: If the outdated-version of the ultraplonk_verifier is already installed, the following command should be used instead of the command above)

cargo install --features bins --path . --force

• 3/ Check whether or not the ultraplonk_verifier version is v0.3.0:

noir-cli -V

This result must be noir-cli 0.3.0.

ZK circuit - Generate (Prove) an Ultraplonk proof in Noir

• 1/ Move to the ./circuits directory:

cd circuits

• 2/ Create the Prover.toml file by coping the example file (Prover.example.toml) in the ./circuits directory.

cp Prover.example.toml Prover.toml

• 3/ Write the input data (Health Records/Data) should be written in the Prover.toml.
  • [NOTE]: This input data would be assumed that a Health Data Provider input their Health Records/Data. And then, this will be used for generating a ZK proof (Ultraplonk proof) in Noir in the subsequent process.
  • [NOTE]: Each revealed data (i.e. revealName) should be written in "Boolean" type. But, it should be written in a string number (True: "0" / False: "1").

name = ""
walletAddress = "<EOA /or SmartContractWallet addresss of a Health Data Provider>"
height = ""
weight = ""
age = ""
gender = ""
race_type = ""
blood_type = ""
blood_pressure_systolic = ""
blood_pressure_diastolic = ""
heart_rate = ""
average_hours_of_sleep = ""
revealName = ""
revealWalletAddress = ""
revealAge = ""
revealGender = ""
revealHeight = ""
revealWeight = ""
revealRaceType = ""
revealBloodType = ""
revealBloodPressureSystolic = ""
revealBloodPressureDiastolic = ""
revealHeartRate = ""
revealAverageHoursOfSleep = ""

• 2/ Run the build.sh to run ZK circuit

sh build.sh

• 3/ The UltraVerifier contract (contract.sol) and proof and vk in Noir would be generated under the ./circuits/target.

ZK circuit - Test

• Run the circuit_test.sh to test the ZK circuit.

cd circuits
sh circuit_test.sh

UltraPlonk zk-SNARK Verifier powered by zkVerify - Convert an original Ultraplonk proof in Noir to an Ultraplonk proof in zkVerify version

• 1/ Move to the ./circuits/zkVerify/ultraplonk_verifier directory:

cd circuits/zkVerify/ultraplonk_verifier

(NOTE: The ./circuits/zkVerify/ultraplonk_verifier would be the ultraplonk_verifier v0.3.0 powered by zkVerify team. Please make sure the version is v0.3.0)

• 2/ Convert an given original Ultraplonk proof to the zkVerify version of Ultraplonk proof

sh convert_ultraplonk_to_zkverify_proof.sh

• 3/ The three files (proof, pubs, vk) in zkVerify version would be generated under the ./circuits/zkVerify/output_zkverify_version_of_proof_pubs_vk directory.

  • 2 type (.hex, .bin) of files would be generated for the three files respectively.

• 4/ Create the ultraplonk_health_data_sharing_zkv.json by coping the example file (ultraplonk_health_data_sharing_zkv.example.json) in the ./circuits/zkVerify/final-output/ directory.

cp ultraplonk_health_data_sharing_zkv.example.json ultraplonk_health_data_sharing_zkv.json

• 5/ Copy the arguments-copied from the .hex version of the three files-generated in the ./circuits/zkVerify/output_zkverify_version_of_proof_pubs_vk directory. Then, it should be pasted to the three properties (vk, publicSignals, proof) in the ./circuits/zkVerify/final-output/ultraplonk_health_data_sharing_zkv.json.

Smart Contract - Compile

• Compile the smart contracts

sh ./buildContract.sh

Smart Contract - Test

• Run the test of the HealthDataSharingViaNoirHelper.t.sol, which is the test file of the HealthDataSharingVerifier.sol.

sh ./test/runningTest_2.sh

Smart Contract for Hashing - Test

• Run the test of the HashingWithKeccak256.t.sol

sh ./test/hashing/runningTest_hash_1.sh

• Run the test of the HashingWithSha256.t.sol

sh ./test/hashing/runningTest_hash_2.sh

Smart Contract - Deployment (on EDU Chain)

• NOTE: Each Smart Contract has been deployed on EDU Chain. See the "Deployed-smart contracts on EDU Chain (testnet)" paragraph above in this README.

• 1/ Create the .env file by coping the example file (.env.example) in the root directory.

  • Then, you should add a private key of your deployer address to the EDU_CHAIN_PRIVATE_KEY.

cp .env.example .env

• 2/ Deploy all contracts on EDU Chain (testnet) by running the script/DeploymentAllContracts.s.sol

/// [NOTE]: Execute the following at the root directory.

forge script script/DeploymentAllContracts.s.sol --broadcast --private-key <EDU_CHAIN_PRIVATE_KEY> \
    ./contracts/zkv-attestation-contracts/interfaces/IZkVerifyAttestation.sol:ZkVerifyAttestation \
    ./circuits/target/contract.sol:UltraVerifier \
    ./contracts/circuits/HealthDataSharingVerifier.sol:HealthDataSharingVerifier \
    ./contracts/HealthDataSharingExecutor.sol:HealthDataSharingExecutor --skip-simulation

Frontend (UI)

• Prequisities

  • Node 18+
  • zkVerify Wallet

• 1/ Move to ./app directory

cd app

• 2/ Create the .env file by coping the example file (.env.example) in the ./app directory.

cp .env.example .env

• 3/ Install

npm install

• 4/ Install zkverifyjs (v0.6.0)

npm i zkverifyjs

• 5/ Run

npm run dev

• 5/ Open the WebApp (http://localhost:3000) on your Web Browser (i.e. Google Chrome).

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References and Resources

• zkVerify:

  • High-Level dApp Architecture: https://docs.zkverify.io/tutorials/porting-dapp#high-level-dapp-architecture
  • zkVerify Architecture: https://docs.zkverify.io/overview/introduction_what_is_zkverify/core_components
  • zkVerify relevant links (i.e. Deployed contract addresses, Block Explorer, Fancet): https://docs.zkverify.io/relevant_links

• Noir:

  • Doc: https://noir-lang.org/docs/getting_started/quick_start

• EDU Chain:

  • Block Explorer: https://edu-chain-testnet.blockscout.com
  • Doc (icl. RPC, Fancet, etc): https://devdocs.opencampus.xyz/build/