World’s First zk-Guessing for the World Cup Games

zCloak Network is holding the world’s first zero-knowledge-based World Cup Guessing Event with its partners. In this event, you can prove whether your guess is correct (e.g. your team enters semi-finals), without telling anyone what your guess is. Here you will get a taste of zCloak Network’s efforts to protect privacy again.

All participants will be rewarded with NFT, OAT and more. The winners will split a $2000 reward pool and win precious Mint Whitelist.

Prize Pool

For Winners: $2000 from zCloak Network; 5 Player Pass NFT Whitelist from Macondo

For every participant: Credential from zCloak; OAT/ POAP from BuidlerDAO, Flock&Tusima, Mirror World, MoleDAO, SnapFingersDAO, Web3Go.

This prize pool is certified by LegalDAO.

Participation Timeline

Phase I — Guess and Record

Present — UTC 12:00, Dec. 9

At this phase, you can guess the champion team and record it as a verifiable credential (VC). Before the deadline, you need to share your credential with the zCloak verifier to make a commitment. Note that you will make a selective disclosure of your credential — you only share your discord user name and the verification code (your credential hash will be recorded) with zCloak for membership verification, but keep your guessing secret to yourself.

Phase II — Zero-Knowledge Proof for Semi-Finals

Dec. 12 — Dec. 16

At this phase, you can prove whether your guess reaches the Semi-Finals without revealing your guess to anyone by use of zero-knowledge proof. Participants who guess correctly will have the chance to win an additional prize ($1,000 pool for 20 winners).

Phase III — Who is the champion?

Dec. 18 — Dec. 20

At this phase, you can announce your guess and zCloak verifier will verify if it is the champion. The eventual winner has the chance to win an additional prize ($1,000 pool and 5 whitelists for 5 winners).

Phase IV — Claim your prizes

Dec. 21

On this day, we will reveal how to claim your rewards. Please keep your DID mnemonics and your backup DID JSON file safe to collect the rewards.

Guide — Phase I

1. Create your zCloak Account

Click this link:

1.1 Click ‘Create account’ to get your first zkID account

Note: All users will need to create a new account as we have adopted an updated version of DID protocol.

1.2 Create Password

All your data is encrypted by this password. Please keep your password safe.

1.3 Generate mnemonic

The mnemonic is the last approach to restore your DID account. Please keep it in a safe place.

1.4 DID key backup JSON file

After confirmation, a DID backup JSON file will be downloaded to your computer. You can restore your DID account in another browser with your password and this DID backup JSON file (or with your mnemonics). Keep the file safe.

2. Make the guessing with verifiable credential

After creating your account, please click this link to enter our Credential Platform:

2.1 Switch your role

Now your role is claimer, who is the owner of the Verifiable Credential (VC). To issue a VC that contains your guessing of the champion, you need to switch your role to ‘Attester’, who can attest or issue a VC to others or to him/herself.

Click this button to switch your role from claimer to attester.

2.2 Issue

Click ‘Issue’ of the menu and ‘Issue’ of the WCG Ctype to issue the guessing VC.

Click ‘Issue to myself’ to automatically fill in your own DID.

Note: If you encounter ‘The DID Document not found’, please wait a moment and refresh the page again since it takes some time to get your identity on the blockchain.

2.3 Finish your identity verification

Join our Discord ( and get your verification code from the ‘zkid-verify’ channel.

Type your whole Discord ID and Verification Code. Then you can choose your guess of the champion team.

2.4 Submit

After submitting, you can see a notification as follows:

3. Verify your VC to record your participation

Congratulations! Now you have finished guessing and got a Verifiable Credential to prove it!

To ensure every DID only chooses one team and the guessing is done before the deadline, you should share your credential hash and some verification information with zCloak verifier. Please note this is just for data commitment purpose. Your guessed team is a secret.

3.1 Switch your role

In order to view and manage your credentials, you should switch your role to ‘Claimer’.

3.2 Download and store your VC

Now you can view your VC. Please note that your VC data is saved in your browser cache. zCloak doesn’t save any of your VC data. You can download the VC as a json file and keep it in a safe place.

If you use other browsers or devices, you can import this VC file. If you lose your VC file, NOBODY can recover it for you. This is part of your responsibility in order to control your own data.

3.3 Share your VC information

At this step, please share the Discord UserName and Verification Code from your VC. We only record the first share. Make sure you only share these two fields or you will be disqualified from the event.

The Receiver DID is:


All information ticked will be sent to us. To avoid disclosing your guess, please DO NOT tick ‘Champion Team’. Otherwise, you will be DISQUALIFIED.

3.4 View the feedback

Congratulations! After getting the feedback in the ‘Notifications’, you have finished all the tasks in phase I.

3.5 Retweet your VC

Now you can Reweet your VC to your friends as follows. Thank you for participating in this event! Please wait for our guidelines for the next phases.

Notes on the technical ingredients: the DID method — the “zk” method — used in this event is implemented by zCloak Network and registered in the W3C. The zero-knowledge proof computation is based on the Polygon Miden VM in the zkID wallet. User DID documents (not credential) are stored in Arweave. zCloak Network will compose a separate article to explain the cryptographic elements used in this event.

About zCloak Network

zCloak Network is a privacy-first DID and verifiable computation infrastructure. It aims to deliver the Web3 dream of Self-Sovereignty by moving both the storage and the computation of user data into user device from centralized servers. The integrity of user computation is proven by a STARK-based ZK-VM in a browser extension. zCloak’s W3C compatible DID system can mirror real-world legal status and reputation in DeSoc. With zCloak Network, people can use their real-world data for e.g. DeFi, Identity, Biometric applications without disclosing their privacy. zCloak Network is chain-agnostic — its identity and ZKP service can be served for most public blockchains.




Terms & Conditions:

zCloak Network reserves the right to cancel or amend any Activity, Activity Rules, or Details at our sole discretion.

This campaign is open internationally, but restrictions due to compliance regulations for different jurisdictions apply. Residents from the United States and OFAC sanctioned countries are not permitted to join this contest. The team is not responsible for any legal repercussions incurred due to the non-compliance of participants. Please consult the respective laws governing your region for the most accurate information.



zCloak Network is privacy-preserving DID and computing platform. Website:; Product:

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zCloak Network is privacy-preserving DID and computing platform. Website:; Product: