Tokenized Incentive System for Public Transport

Web2 + Web3-inspired integration: Supabase (auth/db) + cryptographic hash-chain ledger (tamper-evident, no wallet needed)

How the "blockchain" works

Instead of a real chain, each reward entry is SHA-256 hashed with the previous entry's hash — forming a tamper-evident chain stored in Supabase. Any modification to a past record breaks all subsequent hashes, making it auditable and immutable in practice.

entry_hash = SHA256(userId | distance | tokens | timestamp | prev_hash)

No wallet. No gas. No MetaMask. Same tamper-evidence story.

Setup

1. Supabase

1. Create a project at https://supabase.com
2. Run supabase/schema.sql in the SQL Editor
3. Deploy the Edge Function:

supabase login
supabase link --project-ref your-project-ref
supabase functions deploy log-trip

# Set secrets (only two needed now)
supabase secrets set SUPABASE_URL=https://your-project.supabase.co
supabase secrets set SUPABASE_SERVICE_ROLE_KEY=your_service_role_key

2. Frontend

cd frontend
npm install
cp .env.example .env   # fill in Supabase URL and anon key
npm run dev

Deploy to Vercel: connect your repo and set the same env vars in the Vercel dashboard.

Architecture

User (browser)
  └─> React frontend (Vercel)
        └─> Supabase Auth (login/signup)
        └─> Supabase Edge Function (log-trip)
              └─> trips table (trip records)
              └─> profiles table (token balance)
              └─> reward_ledger table (hash-chain, append-only)

Token Calculation

tokens = distance_km × 10

No wallet required. The hash-chain ledger provides tamper-evidence without any blockchain infrastructure.