Fastest wallet app where you use face to zkPay and pay without latency.
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CzechOut is a smart wallet application that enables seamless login and payment using Face ID and a personal PIN. Your facial data is securely encrypted in combination with your email and secret PIN, ensuring strong authentication while preserving user privacy.
At the core of the system is a registry and delegate smart contract, which manages encrypted identity data and links it to the correct externally owned account (EOA).
We help user to upgrade their EOA into a smart account, no gas fee and enabling access and control from any trusted device with face ID and pin—especially useful if the user loses their phone or physical wallet.
When making a payment, users have the flexibility to choose between two transaction types: EIP-7702 transactions for native account abstraction support. Yellow's state channel transactions, which are chain-abstract, off-chain, gasless, and offer instant confirmation with no waiting time.
The wallet dashboard also includes a suite of features to manage and interact with your digital assets. Some of the key functionalities include: Viewing and managing your token balances Monitoring transaction history Collect Blockscout merits if using Yellow state channel to pay. zkRecovery
zkRecovery allows user to reset their pin using zk email proof and zk web proof with vlayer to proof the ownership of the email and familiarity with the transaction habits of their own account.
CzechOut brings together security, flexibility, and convenience—making it an ideal solution for modern digital payments.
We use @vladmandic/human for real-time facial recognition in the browser. Once a face is captured: It is converted into a stable embedding vector. The credentials is encrypted on the client side using hash of the user’s email and secret PIN and other information. And the whole data go through circum zk circuit to ensure that the secret is not revealed on chain.
The resulting encrypted biometric hash is then registered to our Registry Smart Contract, which maps this identity to the user's EOA wallet address. Then we ask for users' consent for us to help him upgrade eoa to smart account. We use a relay account to waive the gas fee for user to upgrade to our delegation contract. The result can be seen with Blockscout explorer. With smart account, users can therefore pay with face and secret pin credentials.
We built two kinds of transactions. One type of transaction is initiated via the EIP-7702 smart account entry point. Use only the face and pin to send a transaction. For more seamless and gasless experience, we integrated the Yellow Network state-channel Nitrolite SDK: Upon registration, user funds can be deposited and are abstracted into off-chain state channels. When initiating payments, the system checks whether the recipient is also registered. If so, funds are transferred off-chain instantly, with no latency and no fees. This is ideal for fast, low-cost use cases like micro-payments and in-store transactions.
To recover pin, users generate email proof to proof the ownership of the email registered to the account and web proof for familiarity to their own account and then proof to on chain verifier contract. These proofs are generated and verified using contracts modified from vlayer's email and web proof templates. Upon successful verification, users are allowed to reset their PIN securely without exposing their identity or re-registering facial data.
And with the zk circuit contract entrypoint, we can moreover make sure private validation of credentials during face-PIN verification and recovery.
To encourage adoption of Yellow's off-chain rails, we built a reward system on top of Blockscout APIs: We monitor transactions routed via state channels. If users transact with supported merchant addresses or within certain rulesets, they receive Blockscout merits. Rewards are recorded in a hybrid on-chain/off-chain ledger, tying incentives directly to decentralized transaction behavior.
We use these mix of technologies and of course our favorite AI coding helper to make such many complicated functions in 36 hours.