Success stories

Pioneering Off-Chain KYC for On-Chain Access Control

  • Ethan Lippman

    Ethan Lippman

    Product Manager at EthSign

  • 98.2%

    pass rate

  • 14 sec

    median verification time

  • 2024

    start of work with Sumsub

In January 2024, ZetaChain, a valued customer of TokenTable, sought to organize a KYC-gated airdrop. This involved crafting a personalized TokenTable airdrop claiming interface, ensuring a smooth and compliant airdrop experience for ZETA recipients and the ZetaChain team.

Embracing the idea of progressive decentralization, L1 blockchains carry out airdrops to distribute network ownership among their community. Active community members, contributing through tasks like deploying smart contracts, testing applications, and fostering ecosystem growth, receive proportional rewards based on the value they bring to the network.

The Challenge

ZetaChain sought a reliable verification provider to conduct ID verification for their airdrop. After passing KYC verification, users gained access to the TokenTable app to claim a set amount of ZETA tokens. Users rely on a wallet address instead of traditional accounts to interact with blockchain-based applications. This wallet serves as their identifier for authentication, interacting with smart-contract-based applications such as TokenTable and receiving/sending crypto tokens.

The main hurdle in this integration was that TokenTable’s backend operates on smart contracts deployed on blockchains. Since Sumsub verification occurs off the blockchain (“off-chain”), the TokenTable team had to devise a secure solution to integrate each user’s verification status onto the blockchain for the TokenTable backend to retrieve.

Why Sumsub?

ZetaChain required KYC and AML checks for contributors receiving airdrops exceeding 200 ZETA coins to comply with regulations. Additionally, they restricted airdrop claims from locations sanctioned by OFAC.

Ethan Lippman

Ethan Lippman

Product Manager at EthSign

Opting for Sumsub’s top-tier verification services over on-chain KYC providers, we integrated Sumsub and SIGN Protocol. This allowed the seamless porting of KYC status onto the blockchain.

The Solution

Sumsub verification ensured that ZetaChain avoided distributing tokens to individuals under sanctions or blocklists.

ZetaChain’s airdrop process involved several steps:

  1. Whitelisted wallets from non-sanctioned regions connected to
  2. Claimers checked their available ZETA and any lockup terms.
  3. Users completed KYC verification via Sumsub, submitting their government ID.
  4. To link their address and KYC verification status, claimers used SIGN Protocol to sign an attestation message (a hash of their address and KYC status).
  5. The TokenTable Unlocker smart contract validated the KYC verification statuses before enabling the associated wallet to claim its ZETA airdrop.

To prevent unverified addresses from claiming ZETA via TokenTable, each recipient address’s off-chain KYC verification status was relayed to TokenTable’s Unlocker smart contract.

Implementing the SIGN Attestation Protocol alongside Sumsub served two purposes: 

  1. Linking the airdrop recipient’s wallet address to their KYC verification status
  2. Porting recipient addresses’ KYC verification status on-chain for validation by TokenTable’s Unlocker smart contract


The integration with Sumsub was straightforward and completed in less than a week. Designing the solution to transfer users’ KYC verification statuses onto the blockchain using the SIGN Protocol took approximately two weeks.

The Results

As a result, a total of 17,789,923 ZETA was airdropped to KYC-approved claimers, valued at $29,709,171.41.

Ethan Lippman

Ethan Lippman

Product Manager at EthSign

We think this is a pioneering case of utilizing off-chain KYC as a criterion for on-chain access control. TokenTable is enthusiastic about assisting Sumsub and blockchain-based teams in implementing KYC solutions that offer robust KYC procedures, trustless architecture, and user-friendly experiences.

  • Crypto
  • Singapore/ USA

TokenTable by EthSign is used by web3 companies to automatically unlock, distribute, and oversee a company’s token supply.


2021 year founded
20 employees
EthSign – 423,980 users
TokenTable – ~15,000 users
With Sumsub since 2024

Explore other success stories

Start exploring Sumsub today