ProofChain

ProofChain is a proof‑of‑existence dApp built on Ethereum Sepolia, letting users anchor document fingerprints (IPFS CIDs / hashes) on‑chain and verify them later via shareable links.

The frontend is a modern Next.js App Router app with a Web3 SaaS feel, and the backend logic is a simple, auditable Hardhat smart contract.

Features

Proof creation
- Upload any file to IPFS (via Pinata).
- Get a CID and register it on Ethereum Sepolia with a human‑readable title.
- Transaction status + confirmations surfaced in the UI.
Verification
- Public verification page: /verify/[proofId]
- Shows title, owner address, timestamp, IPFS link.
- Copyable share link so anyone can independently verify proofs.
Dashboard
- Wallet‑gated /dashboard page.
- Lists only proofs created by the connected wallet.
- On‑chain visualization: animated chain of blocks with Genesis block, pulsing glow, and data‑flow connectors.
UX / UI
- Modern, responsive layout (desktop + mobile).
- Navbar with routing: Home, Create, Verify, Dashboard, About.
- Wallet connect + disconnect (desktop + mobile).
- Clean dark mode‑friendly aesthetics (radial gradients, glassmorphism).
Smart contract
- Minimal ProofRegistry contract that stores:
  - owner (address)
  - ipfsHash (IPFS CID or hash)
  - title (string)
  - timestamp (uint256)
- Read helpers: getProof(id) and getProofs() for small datasets.

Tech Stack

Frontend
- Next.js 16 (App Router)
- React + TypeScript
- Tailwind CSS v4 (inline @theme)
- wagmi v3 + viem + ethers v6
- WalletConnect, MetaMask / injected providers, Coinbase Wallet
Smart Contracts / Tooling
- Solidity ^0.8.20
- Hardhat + @nomicfoundation/hardhat-toolbox
- TypeChain
Infra
- Ethereum Sepolia network
- IPFS via Pinata

Project Structure

ProofChain/
  contracts/
    ProofRegistry.sol        # Solidity contract
  scripts/
    deploy.ts                # Hardhat deployment script
  src/
    app/
      page.tsx               # Landing page (/)
      create/page.tsx        # Create proof (/create)
      verify/page.tsx        # Verify by ID input (/verify)
      verify/[id]/page.tsx   # Public proof page (/verify/[id])
      dashboard/page.tsx     # Wallet dashboard + visualization
      about/page.tsx         # About + use cases
      api/pinata/route.ts    # IPFS upload API (Pinata)
      layout.tsx             # Root layout + NavBar + providers
      globals.css            # Tailwind + global styles
    components/
      NavBar.tsx
      WalletStatus.tsx
      FileUpload.tsx
      ProofForm.tsx
      ProofList.tsx
      ProofChainVisualizer.tsx
    lib/
      abi/proofRegistry.ts   # ABI + address helper
      wagmi/config.ts        # wagmi/viem client config
  hardhat.config.ts
  package.json
  env.example
  README.md                  # (this file)

Prerequisites

Node.js 18+
npm
Funded Sepolia wallet for deployment / interactions
Pinata account (for IPFS uploads)

Setup

Install dependencies

npm install

Configure environment variables

Copy the example file and fill in values:

cp env.example .env.local

Required values:

Frontend
- NEXT_PUBLIC_SEPOLIA_RPC_URL – HTTPS Sepolia RPC endpoint
- NEXT_PUBLIC_WALLETCONNECT_PROJECT_ID – WalletConnect Cloud project id
- NEXT_PUBLIC_PROOF_CONTRACT_ADDRESS – Deployed ProofRegistry address
Hardhat / deployment
- SEPOLIA_RPC_URL – Same or separate Sepolia RPC endpoint
- PRIVATE_KEY – Deployer wallet private key (Sepolia)
- ETHERSCAN_API_KEY – Optional, for contract verification
IPFS / Pinata
- PINATA_API_KEY
- PINATA_SECRET_API_KEY

Running the App

Development server

npm run dev
# visit http://localhost:3000

Changes are hot‑reloaded.

Hardhat tests

npm run test:contracts

Deploy contract to Sepolia

npm run deploy:sepolia

After deployment, set:

NEXT_PUBLIC_PROOF_CONTRACT_ADDRESS to the printed contract address,
then restart npm run dev.

(Optional) Verify on Etherscan:

cross-env TS_NODE_PROJECT=tsconfig.hardhat.json npx hardhat verify --network sepolia <deployed_address>

Key Flows

Create a proof (`/create`)

Connect a wallet via the navbar.
Upload a file using the IPFS upload card (Pinata).
Copy the resulting CID.
In the proof form:
- Enter a Title (e.g., “NDA v1 PDF”).
- Paste the CID (or any hash).
Click Register Proof to anchor it on Ethereum Sepolia.

Verify a proof (`/verify` and `/verify/[id]`)

/verify: enter a Proof ID and click Verify Proof to redirect.
/verify/[id]: public page that:
- Validates ID using proofCount.
- Fetches proof via getProof(id).
- Displays title, owner, timestamp, IPFS link.
- Offers a Copy link button for sharing.

Dashboard (`/dashboard`)

Requires a connected wallet.
Top: animated chain of cubes representing the wallet’s proofs.
- Genesis Block = first (oldest) proof.
- Pulsing glow + animated connectors to feel “on-chain”.
Bottom: table/list of proofs filtered to the connected address.

Scripts

npm run dev            # Start Next.js dev server
npm run build          # Build for production
npm run start          # Start production server
npm run lint           # Run ESLint
npm run hardhat        # Run Hardhat CLI
npm run test:contracts # Run Hardhat tests
npm run deploy:sepolia # Deploy ProofRegistry to Sepolia

Security / Notes

Only minimal metadata + hash/CID are stored on‑chain; documents themselves stay off‑chain.
This is a demo‑grade contract and UI:
- No advanced access control.
- No gas optimizations or batching.
For production:
- Consider multi‑network support (L2s).
- Add rate limiting & auth around the Pinata API route.
- Review and harden contract with audits.

License

MIT. See LICENSE (add one if not present).

Credits

Built with:

ProofChain

Proof-of-existence dApp built with Next.js 14 (App Router), wagmi + ethers v6, Tailwind CSS, and Hardhat. Deploys a ProofRegistry contract to Ethereum Sepolia to anchor document hashes or CIDs on-chain.

Stack

Next.js 14 + TypeScript + App Router
wagmi 3 + ethers v6 + React Query
Tailwind CSS (v4, @import-based)
Hardhat + @nomicfoundation/hardhat-toolbox
Network: Ethereum Sepolia

Project structure

src/app – UI pages and layout
src/components – Wallet UI and proof form/list components
src/lib/abi – Contract ABI + address helper
src/lib/wagmi – wagmi client configuration
contracts – Solidity sources (ProofRegistry.sol)
scripts – Hardhat deployment scripts
test – Hardhat tests

Prerequisites

Node.js 18+
npm
Funded Sepolia wallet (for deployment/interaction)

Setup

Install dependencies

npm install

Copy env template and fill values

cp env.example .env.local

Required values:

NEXT_PUBLIC_SEPOLIA_RPC_URL – HTTPS RPC endpoint
NEXT_PUBLIC_WALLETCONNECT_PROJECT_ID – WalletConnect Cloud project id
NEXT_PUBLIC_PROOF_CONTRACT_ADDRESS – Deployed ProofRegistry address
SEPOLIA_RPC_URL, PRIVATE_KEY, ETHERSCAN_API_KEY – used by Hardhat

Run the web app

npm run dev
# open http://localhost:3000

Hardhat

All Hardhat commands automatically use tsconfig.hardhat.json via cross-env.

Run tests:

npm run test:contracts

Deploy to Sepolia:

npm run deploy:sepolia

After deployment, set NEXT_PUBLIC_PROOF_CONTRACT_ADDRESS to the printed address.

IPFS via Pinata

Add to .env.local:

PINATA_API_KEY=...
PINATA_SECRET_API_KEY=...

Use the "Upload to IPFS (Pinata)" widget in the UI to pin any file. Progress and resulting CID will be shown. Secrets stay server-side; the client only calls your /api/pinata route.
Verify (optional):

cross-env TS_NODE_PROJECT=tsconfig.hardhat.json npx hardhat verify --network sepolia <address>

DApp usage

Ensure NEXT_PUBLIC_PROOF_CONTRACT_ADDRESS points to a deployed ProofRegistry on Sepolia.
Connect a wallet (injected, WalletConnect, or Coinbase Wallet).
Submit a label and proof hash/CID; wait for confirmations.
Recent proofs render in the list with submitter, timestamp, and stored hash.

Notes

Contract is intentionally simple for demo purposes (stores small proof metadata on-chain).
Tailwind v4 uses @import "tailwindcss"; and inline theme tokens; no config file is needed.

Name		Name	Last commit message	Last commit date
Latest commit History 10 Commits
artifacts		artifacts
cache		cache
contracts		contracts
public		public
scripts		scripts
src		src
test		test
typechain-types		typechain-types
.gitignore		.gitignore
README.md		README.md
eslint.config.mjs		eslint.config.mjs
hardhat.config.ts		hardhat.config.ts
next.config.ts		next.config.ts
package-lock.json		package-lock.json
package.json		package.json
postcss.config.mjs		postcss.config.mjs
tsconfig.hardhat.json		tsconfig.hardhat.json
tsconfig.json		tsconfig.json

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ProofChain

Features

Tech Stack

Project Structure

Prerequisites

Setup

Running the App

Development server

Hardhat tests

Deploy contract to Sepolia

Key Flows

Create a proof (`/create`)

Verify a proof (`/verify` and `/verify/[id]`)

Dashboard (`/dashboard`)

Scripts

Security / Notes

License

Credits

ProofChain

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ProofChain

Features

Tech Stack

Project Structure

Prerequisites

Setup

Running the App

Development server

Hardhat tests

Deploy contract to Sepolia

Key Flows

Create a proof (/create)

Verify a proof (/verify and /verify/[id])

Dashboard (/dashboard)

Scripts

Security / Notes

License

Credits

ProofChain

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Prerequisites

Setup

Hardhat

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DApp usage

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