Anonymous Provision of Services via Blockchain

Installation

Install Powergate (IPFS + Lotus)

Follow the installation instructions here to set up Powergate, which combines IPFS and Lotus.

Install Ganache — Ethereum Development Blockchain

1. Follow the instructions here to install Ganache.
2. Start a Docker container with Ganache:

   docker run --detach --publish 8545:8545 trufflesuite/ganache:latest

3. Import one of the generated accounts into MetaMask.

Install Monero

1. Download and install the Monero CLI wallet binaries from the official Monero website.
2. Use monero-wallet-cli to interact with the daemon. Refer to the user guide for details.

Start two nodes on a stagenet that only communicate with each other:

monerod --stagenet

Then start the client's CLI wallet on the same machine:

monero-wallet-cli --stagenet

Mine some blocks:

start_mining <yourwalletaddress> 1

Repeat the above steps for the Service Provider's (SP) CLI wallet:

monero-wallet-cli --stagenet

Mine some blocks as well:

start_mining <yourwalletaddress> 1

After a short time, both wallets should show a balance. Check the balance with the refresh command.

• Client's address: 5Azsn5VgEje8ocGTJcyXNcj2rGdNHEbyNQBJJjrYvCxrJjNCDZuQxoT6caF12TSoNr77WwoEGUsfofQxHG2s84htP7K918K
• SP's address: 5B6PgosHHqXNRgMhGyN25pewMf1VjoCWvGQJRzFYkj3UYZwvTaHfG2gdrSAWxLmgHphhh1Zt1AsvgRj6eBYQb3MW5YSXiUr

Proving to a Third Party You Paid Someone

1. Enable per-transaction proof generation by setting:

   set store-tx-info 1

2. Send a transaction from the client to SP and generate a proof:

   get_tx_key <key>

3. Verify the transaction using:

   check_tx_key TXID TXKEY ADDRESS

Deploy the Smart Contract

1. Navigate to the smart contracts directory:

   cd smartcontracts

2. Connect to the Ganache blockchain with Truffle:

   truffle console

3. Deploy the smart contract:

   migrate --network development

   This will compile the smart contract and output the ABI to webapp/src/contracts/AnonSer.json.

Start the Web App

1. Navigate to the web app directory:

   cd webapp

2. Start the npm server:

   npm start

Flow

1. Client: Opens the web app, which generates a DHKE-compliant key pair and a random provisionId.
2. QR Code: The app generates a QR code containing the public key and provisionId, which the client downloads and prints as a label.
3. Package: The QR code is attached to the materials package (pkg) and delivered to the service provider, optionally with cash.
4. SP: Scans the QR code to retrieve the public key and provisionId.
5. Payment:
   • If paid in cash, SP can immediately publish a Proof of Delivery on the Ethereum smart contract.
   • If not, SP generates a new integrated address for the client, calculates a payment ID, and publishes the Proof of Delivery along with the dedicated payment address.
6. Client: Listens for events on the Ethereum smart contract.
7. Payment: If not paid in cash, the client sends payment to the specified address.
8. Service Provision: SP processes the payment, provides the service, and uploads the results to the Powergate network.
9. Result Delivery: SP publishes the proof of provision to the Ethereum smart contract.
10. Client: Retrieves and decrypts the results from IPFS/Lotus using the smart contract information.

Components

Client's App Responsibilities:

• Generate a random key pair and provisionId.
• Encode the public key and provisionId, generate a QR code, and download it as a printable label.
• Listen for smart contract events and fetch/decrypt provision results from IPFS/Lotus.

SP's App Responsibilities:

• Scan and decode the QR code.
• Publish transactions to the Ethereum smart contract.
• Listen for payments on supported methods.
• Upload provision results to IPFS/Lotus.

User Responsibilities:

• Use the web app, print the QR code, and attach it to the package.
• Deliver the package to the Service Provider.
• Pay for the service, either in cash or via another supported method.
• Notify authorities in case of a conflict.

SP Responsibilities:

• Accept the package with the printed QR code label.
• Handle payments and service provision according to the protocol.

Development

Client App

• Initialized using create-react-app.
• Integrated with web3js for blockchain interaction.
• User interface with options to start new provisions or check provision status.

Server App

• Accept packages and handle payment verification.
• Manage the lifecycle of service provision.