🪂 Foundry Merkle Airdrop CU

A simple and gas-optimized Merkle tree–based airdrop contract built using Foundry.
Users can claim tokens if they are in a predefined Merkle tree and provide a valid EIP-712 signature.

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📦 Features

• ✅ Airdrop protected by a Merkle root (only whitelisted addresses can claim)
• ✅ EIP-712 signature verification (ensures the claim is authorized)
• ✅ Single-claim enforcement (no double-spending)
• ✅ Uses OpenZeppelin libraries for security
• ✅ Built and tested using Foundry

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🧱 Contract Summary

• The contract uses:
  • MerkleProof for validating whitelist
  • EIP712 & ECDSA for verifying claims via off-chain signatures
  • SafeERC20 for safe token transfers
• A user must:
  1. Have a valid Merkle proof
  2. Provide a valid EIP-712 signature
  3. Have not claimed before

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🧪 How to Test It

1. Clone & Install

Documentation

https://book.getfoundry.sh/

Usage

Build

$ forge build

Test

$ forge test

Format

$ forge fmt

Gas Snapshots

$ forge snapshot

Anvil

$ anvil

Deploy

$ forge script script/Counter.s.sol:CounterScript --rpc-url <your_rpc_url> --private-key <your_private_key>

Cast

$ cast <subcommand>

Help

$ forge --help
$ anvil --help
$ cast --help