Certificate NFT

A non-transferable NFT smart contract for issuing certificates on the Mandala Chain. This contract allows authorized entities to mint certificate NFTs with metadata and images stored on IPFS.

Features

• Non-transferable NFTs (Soul-bound tokens)
• IPFS integration for metadata and images
• Fully compliant with ERC721 standard
• Transfer and approval blocking
• Gas-efficient operations

Contract Architecture

The contract inherits from:

• ERC721URIStorage: For storing token metadata
• Ownable: For access control

Key components:

• Minting functionality
• Transfer blocking
• Approval blocking
• Metadata generation
• Event emission

Prerequisites

• Foundry
• Access to Mandala Chain RPC
• IPFS for storing certificate images

Installation

Clone the repository:

git clone <your-repo-url>
cd certificate-nft

Install dependencies:

forge install

Set up environment variables:

# Create .env file with your configuration
RPC_URL="https://mlg1.mandalachain.io"
PRIVATE_KEY="your-private-key"

Deployment

Compile the contract:

forge build

Deploy to Mandala Chain:

forge create src/CertificateNFT.sol:CertificateNFT \
  --rpc-url "https://mlg1.mandalachain.io" \
  --private-key $PRIVATE_KEY \
  --broadcast

Minting Certificates

To mint a new certificate NFT:

# Export contract address
export NFT_CONTRACT="your-contract-address"

# Mint NFT
cast send $NFT_CONTRACT "mintNFT(address,string)" \
  $RECIPIENT_ADDRESS \
  "https://ipfs.io/ipfs/your-image-hash" \
  --rpc-url $RPC_URL \
  --private-key $PRIVATE_KEY

Contract Details

Latest Deployment:

• Network: Mandala Chain
• Contract: 0xcDCf9295EB880C166E73Ef9D42f07eD9c2E1B7Ee
• Explorer: https://niskala.mandalachain.io/address/0xcDCf9295EB880C166E73Ef9D42f07eD9c2E1B7Ee

Testing

Run the test suite:

forge test

The tests cover:

• Basic minting functionality
• Transfer blocking
• Approval blocking
• Owner-only access

Security Features

Non-transferable tokens:

• All transfer functions are blocked
• NFTs cannot be moved once minted

Access Control:

• Only contract owner can mint certificates
• All approval functions are blocked

Metadata Integrity:

• On-chain metadata storage
• Base64 encoded JSON structure
• IPFS integration for immutable storage