DropDis Documentation

v1.0

Where privacy meets payroll. DropDis is a groundbreaking DApp that leverages Zama's fhEVM to enable fully confidential salary distributions.

FHE PoweredEnterprise ReadyGas Optimized

Key Features

End-to-End Encryption

Employee addresses and salaries are encrypted on the client-side and remain private throughout the entire process.

Efficient Batch Processing

Distribute salaries to hundreds of employees in a single, gas-optimized transaction.

Real-Time UI Feedback

Watch as each employee's data is encrypted with a beautiful, responsive interface that shows live status updates.

Interactive Dashboard

Get a complete, historical overview of all salary batches, their status, and detailed payout information.

How It Works: The Magic of FHE

Traditional blockchains are public. With fhEVM, DropDis can perform calculations on encrypted data. Think of it like sending a locked box to the blockchain. The contract can verify the total amount inside the box is correct, but it can't see what's inside until you, the owner, provide the special key.

Add Employee Data

User inputs employee information through the frontend

Encrypt Data Locally

Frontend encrypts data using FHE before sending to blockchain

Submit Encrypted Batch

Encrypted data is submitted to the smart contract

Request Decryption

Contract requests decryption from FHE Oracle

Secure Decryption

Oracle securely decrypts data off-chain

Execute Transfers

Contract distributes salaries with decrypted data

Technology Stack

Blockchain Layer

Technology	Description
Blockchain	Zama fhEVM (Sepolia Testnet)
Language	Solidity ^0.8.24
Environment	Hardhat
Core Library	@fhevm/contracts

Frontend Layer

Technology	Description
Framework	Next.js 16 (App Router)
Language	TypeScript
Styling	Tailwind CSS
Web3 Library	Ethers.js v6
FHE Library	@zama-fhe/relayer-sdk/bundle
Notifications	Sonner

Getting Started

Prerequisites

Node.js v18+
pnpm (recommended), npm, or yarn
A Web3 wallet (e.g., MetaMask) with the Zama Sepolia network configured
Some Sepolia testnet ETH

Clone & Install

git clone https://github.com/unamul/drop-dis.git
cd drop-dis

# Install dependencies
pnpm install

Environment Setup

Create environment file:

frontend/.env.local

MNEMONIC=
INFURA_API_KEY=
ETHERSCAN_API_KEY=

NEXT_PUBLIC_CONTRACT_ADDRESS=0x684468E7fe477AaB7525573106eB88F3D18B9Ce2
PRIVATE_KEY=
BATCH_SIZE=50

Compile & Deploy Contract

# Compile the Solidity code
pnpm compile

# Deploy to Sepolia testnet
pnpm deploy:sepolia

Run the Frontend

From the frontend directory:

pnpm dev

Navigate to http://localhost:3000 to start using DropDis!

Usage Guide

1
Connect Wallet: Ensure your wallet is connected to the Sepolia network.
2
Add Employees: Enter an employee's address and salary. Click Add Employee.
3
Monitor Encryption: The employee appears in the list with a loading spinner. Once encrypted, it turns green. You can add multiple employees simultaneously.
4
Distribute: Once all employees are encrypted, the Distribute Now button becomes active. Click it to submit the batch to the blockchain.
5
Track Progress: The UI shows the live status of the decryption and payment process.
6
View History: Visit the /dashboard to see a complete history of all salary batches. #ComingSoon

Project Structure

DROP-DIS/
│
├── app/                                # Next.js 16 App Router (frontend pages)
│   ├── favicon.ico                     # Website favicon
│   ├── globals.css                     # Global Tailwind / CSS styles
│   ├── layout.tsx                      # Root layout wrapper for pages
│   ├── page.tsx                        # Main landing page of the DApp
│   └── docs/                           # Documentation pages
│       └── page.tsx                    # GitBook-style documentation
│
├── components/                         # Reusable React components for UI
│   ├── BatchStatus.tsx                 # Component to show batch processing status
│   ├── Card.tsx                        # UI card to display employee info
│   ├── EmployeeForm.tsx                # Form to add new employees with encryption
│   ├── EmployeeList.tsx                # List displaying all employees
│   └── FHEVM.tsx                       # Handles Zama FHEVM initialization logic
│
├── contracts/                          # Solidity smart contracts
│   └── DropDis.sol                     # Main contract handling encrypted distribution
│
├── deploy/                             # Deployment scripts for Hardhat
│   └── deploy.ts                       # Script to deploy DropDis.sol to the network
│
├── deployments/                        # Stores deployed contract addresses & metadata
│
├── ignition/                           # Hardhat Ignition scripts (structured deployment)
│
├── lib/                                # Custom libraries (optional utilities or hooks)
│
├── public/                             # Static assets (images, fonts, etc.)
│
├── test/                               # Smart contract tests
│   └── dropDis.test.ts                 # Unit tests for DropDis contract
│
├── types/                              # TypeScript type definitions (e.g. contract types)
│
├── utils/                              # Helper functions and config files
│   ├── abi/
│   │   ├── DropDis.json                # Compiled ABI of DropDis.sol
│   │   └── ABI.ts                      # ABI export helper for frontend
│   ├── contract.ts                     # Ethers.js contract interaction setup
│   └── fheClient.ts                    # Zama FHEVM client initialization (encrypt/decrypt)
│
├── .env                                # Environment variables (private keys, RPC URLs)
│
├── package.json                        # NPM dependencies and scripts
├── hardhat.config.ts                   # Hardhat configuration file
├── tsconfig.json                       # TypeScript configuration
├── next.config.js                      # Next.js configuration
└── README.md                           # Project documentation (GitHub)

Running Tests

This project uses the Zama FHE mock environment for testing, which simulates the entire encryption/decryption flow.

#
pnpm test

Contributing

We welcome contributions! Whether it's a bug fix, a new feature, or an improvement to the documentation, your help is appreciated.

1
Fork the repository.
2
Create your feature branch (git checkout -b feature/amazing-feature).
3
Commit your changes (git commit -m 'Add some amazing feature').
4
Push to the branch (git push origin feature/amazing-feature).
5
Open a Pull Request.

References

A huge thanks to the Zama team for building the future of confidential smart contracts.

Built with the amazing tools from Hardhat , Next.js , and Tailwind CSS .