FHEcard is a privacy-preserving subscription management protocol that bridges the gap between Fully Homomorphic Encryption (FHE) on-chain and traditional Visa/Mastercard payment rails off-chain.

The core problem FHEcard solves is the lack of privacy in traditional bank statements and the inability to control "zombie subscriptions" (services that are hard to cancel). By acting as a firewall between your money and merchants, FHEcard allows you to generate "Ghost Cards" with programmable, encrypted constraints.

The ultimate goal of FHEcard is to enable a user to:

1. Pay Privately: Your bank statement only shows "FHEcard Protocol Funding", while the actual merchant (e.g., Netflix, Tinder) remains hidden cryptographically on-chain.
2. Control Spending: Set private, encrypted rules (e.g., "Max $15/month"). If a merchant tries to charge $16, the FHE smart contract mathematically catches and rejects the violation without ever revealing your actual balance or limit.
3. Settlement Bridge: Utilize an Optimistic Settlement Model to handle the speed mismatch between Visa (milliseconds) and FHE Blockchains (seconds), ensuring instant approvals with cryptographic assurance.

• Layer 1 (The Off-Chain Runner): A Node.js relayer that holds a buffer balance on a card issuing platform (Lithic) and approves transactions instantly based on "Cached Intent."
• Layer 2 (The On-Chain Vault): An FHE-enabled smart contract on Fhenix that holds user funds in eUSDC.
• Layer 3 (The Verification): (Future) TLSNotary implementation to prove authentic web traffic, ensuring the relayer cannot fake charges.

• Blockchain: Fhenix (FHE-EVM), Solidity
• Backend: Node.js, Express
• Card Issuer: Lithic API (Sandbox)