Rozo Tap to Pay

Crypto Native Tap to Pay Between Mobile, Wearables and POS

A Solana smart contract built with the Anchor framework that enables tap-to-pay functionality for token payments.

Features

• Token Authorization: Users can authorize tokens (e.g., USDC) to be spent by the contract
• Merchant Whitelisting: Contract owners can whitelist merchant addresses
• Secure Payments: Only authorized owners can trigger payments from users to merchants
• User Control: Tokens remain in the user's wallet until payment is processed

Architecture

The contract uses Program Derived Addresses (PDAs) to store various states:

1. Program Config: Stores the contract authority (deployer)
2. Owner Accounts: Stores owner addresses that have admin privileges
3. Merchant Accounts: Stores whitelisted merchant addresses
4. Payment Auth: Stores the amount of tokens a user has authorized for payments

Prerequisites

• Solana CLI tools
• Anchor Framework
• Node.js and npm/yarn
• Rust and Cargo

Getting Started

Installation

1. Clone the repository:

   git clone https://github.com/yourusername/rozo-tap-to-pay.git
   cd rozo-tap-to-pay
   

2. Install dependencies:

   npm install
   

3. Generate Solana accounts (deployer and user):

   npm run generate-accounts
   

   This script will:

   • Generate Solana keypairs for deployer and user
   • Save them to the keys/ directory
   • Create a .env file with the paths to these keypairs

4. Fund your accounts with SOL (on devnet):

   npm run fund-accounts
   

   This requires the Solana CLI to be installed and will airdrop SOL to your accounts on devnet.

5. Build the program:

   npm run build
   

Testing

Run the test suite:

anchor test

Usage

Deploying the Contract

1. Update the program ID in Anchor.toml and lib.rs with your own if needed
2. Set up your Solana wallet and ensure it has SOL for deployment
3. Run the deployment script:

   npm run deploy:mainnet
   

For Users

To authorize tokens for payment:

yarn authorize <token_mint_address> <amount>

Example:

yarn authorize EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v 10

This authorizes 10 USDC (assuming the provided address is USDC) for payments.

For Admins

Admin operations:

1. Add an owner:

   yarn admin add-owner <owner_public_key>
   

2. Add a merchant:

   yarn admin add-merchant <merchant_public_key>
   

3. Process a payment:

   yarn admin process-payment <user_public_key> <merchant_public_key> <token_mint_address> <amount>
   

   Example:

   yarn admin process-payment 7KBVGvotfYJwfKJzAfEY5jabbus3MsZTGiALWi67L8Y2 Hm1rJ4DmXZMxXFMPuieeKGgMUJaZ6r7AzWhtKbg94pTY EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v 3
   

   This processes a payment of 3 USDC from the user to the merchant.

Security Considerations

• The contract ensures only authorized owners can add merchants and process payments
• Users maintain control of their tokens until a payment is processed
• Tokens remain in the user's wallet until a specific payment is authorized and processed
• Only whitelisted merchants can receive payments

Environment Variables

Create a .env file with the following variables:

# For deployment
DEPLOYER_KEYPAIR_PATH=/path/to/deployer_keypair.json

# For user operations
USER_KEYPAIR_PATH=/path/to/user_keypair.json

# For admin operations
ADMIN_KEYPAIR_PATH=/path/to/admin_keypair.json

Contract Workflow

1. Initialization: The deployer initializes the contract and becomes the authority
2. Add Owners: The authority adds owners to the contract
3. Add Merchants: Owners add merchants to the whitelist
4. User Authorization: Users authorize tokens for payments
5. Payment Processing: Owners trigger payments from users to merchants

License

ISC License