LegacyVault: Decentralized Inheritance Protocol

Executive Summary

LegacyVault is a non-custodial blockchain-based inheritance solution that ensures your digital assets are safely transferred to your loved ones if something happens to you, while earning passive income through an integrated lending pool. Built on Arbitrum Stylus using both Rust and Solidity, LegacyVault combines the efficiency of Rust with the security of Ethereum to deliver a gas-optimized Dead Man's Switch protocol.

The Problems We Solve

1. Crypto Dies With You

Problem: Over $280 billion in cryptocurrency is estimated to be lost forever due to death, lost keys, or forgotten wallets. Unlike traditional assets, there's no bank or lawyer to help your family recover your funds.

Impact: Families are left with no access to significant wealth, and the crypto ecosystem loses value permanently.

2. Centralized Solutions Require Trust

Problem: Existing inheritance solutions require trusting third parties (custodians, lawyers, or centralized services) with your private keys or assets.

Impact: You sacrifice the core principle of crypto: self-custody and decentralization.

3. Idle Assets Generate No Value

Problem: Most inheritance solutions simply lock up your assets, generating zero returns while waiting (potentially for decades).

Impact: Inflation erodes the real value of your legacy over time.

4. Expensive and Complex Legal Processes

Problem: Traditional inheritance through wills requires lawyers, probate courts, and can take months or years to settle.

Impact: High costs, delays, and potential disputes drain the value of the estate.

5. No Middle Ground Between Active Trading and Cold Storage

Problem: Users must choose between actively managing their portfolio or putting assets in cold storage with no growth potential.

Impact: Missing opportunity for passive, secure yield generation.

Our Solutions

1. Decentralized Dead Man's Switch

How It Works:

• Set a "Heartbeat" interval (e.g., 6 months, 1 year)

• Periodically "Ping" the smart contract to prove you're still active

• If you fail to ping within the interval, the vault automatically unlocks for your beneficiary

• Your beneficiary can claim all assets with one simple transaction

Benefits:

• ✅ No third-party trust required

• ✅ No lawyers, no courts, no delays

• ✅ Fully automated and transparent on-chain

• ✅ You remain in complete control while alive

2. Hybrid Rust + Solidity Architecture

Technology Stack:

• Rust (via Arbitrum Stylus): Core vault logic, lending pool, and token contracts

• Solidity: Factory contract for EIP-1167 minimal proxy pattern

• Why Rust? 10-100x lower gas fees for complex calculations

Architecture:

Factory (Solidity) → Creates Minimal Proxies → Delegates to Vault Logic (Rust)

↓

Lending Pool (Rust)

Benefits:

• Up to 100x cheaper gas costs than pure Solidity

• Rust's memory safety prevents common smart contract vulnerabilities

• Fast execution for time-based operations

• Easy vault creation through proxy pattern

3. Integrated Lending Pool with Compound Interest

How It Works:

• Deposit your USDC into the vault

• Optionally move funds to the lending pool with one click

• Earn 1% daily compound interest (3,778% APY for demo purposes)

• When beneficiary claims, they receive principal + all accrued interest

Interest Growth Example:

Benefits:

• Your legacy grows automatically while waiting

• No manual intervention required

• Transparent on-chain interest calculations

• Can deposit or withdraw anytime while active

4. Gas-Optimized Multi-User System

How It Works:

• One master "Vault Logic" contract written in Rust

• Factory creates minimal proxies (EIP-1167) for each user

• Each proxy weighs only ~200 bytes vs full contract deployment

Benefits:

• ~80-90% cheaper vault creation

• Scales to millions of users efficiently

• Upgradeable logic for bug fixes (with user consent)

Target Consumer

Primary Audience:

• Crypto Holders with Families: Individuals who own cryptocurrency or digital assets and want to ensure their loved ones can access these assets if something happens to them.

• Long-Term Investors: Crypto enthusiasts who are thinking about estate planning and want a trustless, decentralized alternative to traditional inheritance methods.

• Tech-Savvy Professionals: People who understand the importance of digital asset security but don't want to rely on centralized services or traditional legal systems.

Secondary Audience:

• DeFi Users: Cryptocurrency holders looking for passive income opportunities while maintaining control of their assets.

• Early Adopters: Web3 natives who value non-custodial solutions and want to be early users of innovative inheritance protocols.

• Beneficiaries: Family members and loved ones who will inherit digital assets without needing deep technical knowledge.

User Pain Points We Solve:

• "What happens to my crypto if I die?"

• "I don't trust centralized services with my private keys."

• "Traditional wills are expensive and slow."

• "My family doesn't understand crypto."

• LegacyVault provides a simple, trustless, and automated solution!

Main Features

Core Inheritance Features

1. Vault Creation

• Create a personal vault with a few clicks

• Set your beneficiary (can be changed anytime)

• Define heartbeat interval (hours, days, months, years)

• Give your vault a memorable name

2. Heartbeat System (Ping)

• Simple "Ping" button to prove you're alive

• Resets the countdown timer

• Can be automated through various methods (wallet notifications, calendar reminders, etc.)

• Visual countdown display shows time remaining

3. Beneficiary Claim

• Beneficiary receives automatic unlock notification when vault expires

• One-click claim process

• Receives principal + all interest earned

• Works with any ERC-20 token

4. Multi-Asset Support

• Store any ERC-20 token (USDC, ETH, DAI, etc.)

• Mix multiple tokens in one vault

• Each token claimed separately for gas efficiency

DeFi Features

5. Lending Pool Integration

• Move funds from vault to lending pool with one transaction

• Earn 1% daily compound interest

• View real-time balance growth

• Automatic withdrawal on claim

6. Total Value Dashboard

• See combined value across:

  • Vault balance (idle funds)

  • Lending pool balance (earning interest)

  • Total USDC value with live interest calculation

  • Transaction history tracking

  • Visual charts and statistics

User Experience Features

7. Interactive Faucet

• Get test USDC tokens for demo purposes

• Simple, clean interface

• Clear transaction status tracking

• Network-specific instructions

8. Multi-Language Support

• English, Indonesian, and Chinese locales

• Dynamic content translation

• Accessible to global audience

9. Wallet Integration

• Privy wallet authentication

• Connect with social accounts or crypto wallets

• Supports MetaMask, WalletConnect, and more

• Seamless Web3 experience

10. Pixel Art Theme

• Engaging retro-style UI

• Gamified elements for better UX

• Smooth animations and transitions

• Professional yet approachable design

Technical Features

11. Arbitrum Stylus Innovation

• First inheritance protocol using Rust on Ethereum

• Showcases Stylus capabilities

• Production-ready WASM smart contracts

• Fully auditable and verifiable

12. Security & Transparency

• All logic open source

• Verifiable on-chain calculations

• No admin keys or backdoors

• Immutable core logic

13. Testing & Deployment

• Comprehensive test suite

• Deployed on Arbitrum Sepolia testnet

• Verified contracts on block explorer

• Production-ready architecture

Technical Architecture

Smart Contracts

Frontend Stack

• Framework: Next.js 15 with React 19

• Styling: Tailwind CSS + Custom Pixel Art Theme

• Web3: Viem, Wagmi, RainbowKit

• Auth: Privy (wallet + social login)

• UI Components: Radix UI + shadcn/ui

• Internationalization: Multi-language support

How It Works - User Journey

For the Vault Owner:

1. Connect Wallet → Sign in with crypto wallet or social login

2. Create Vault → Set beneficiary, duration, and vault name

3. Deposit Assets → Transfer USDC or other ERC-20 tokens

4. Activate Lending → Move funds to lending pool to earn interest

5. Stay Active → Ping the vault periodically to reset the timer

6. Monitor Growth → Watch your legacy grow with compound interest

For the Beneficiary:

1. Wait → Vault owner becomes inactive or passes away

2. Get Notified → Vault unlocks automatically after duration expires

3. Claim Assets → One-click claim of principal + interest

4. Receive Funds → Assets transferred directly to beneficiary wallet

Use Cases

1. Individual Inheritance
Store your crypto safely with automatic transfer to your spouse, children, or chosen beneficiary.

2. Business Succession
Ensure company treasury funds are transferred to new leadership if founder becomes incapacitated.

3. Charitable Giving
Set up automated donations to nonprofits after a certain period of inactivity.

4. Joint Accounts
Create vaults for family members with staggered heartbeat intervals.

5. Emergency Fund
Passive income generation while maintaining access control and automatic failover.

Competitive Advantages

Future Roadmap

Phase 1: Core Features (Current)

• Vault creation and management

• Heartbeat/ping system

• Beneficiary claiming

• Lending pool integration

• Frontend dashboard

Phase 2: Advanced DeFi (Next)

• Multi-sig support for joint accounts

• Integration with Chainlink Automation for auto-claims

• Support for more assets (ETH, wrapped tokens, NFTs)

• Adjustable interest rates based on market conditions

Phase 3: Enterprise (Future)

• Business treasury management

• Multi-beneficiary distribution (percentage splits)

• Time-locked vesting schedules

• Compliance and reporting tools

📊 Market Opportunity

• Total Crypto Users: ~500 million worldwide

• Estate Planning Market: $500+ billion annually

• Lost Crypto: $280+ billion and growing

• Target Audience: High-net-worth crypto holders, elderly crypto investors, business owners

Problem-Market Fit: Every crypto holder faces the same question: "What happens to my crypto if I die?"

Why LegacyVault Wins

• First Mover: First inheritance protocol on Arbitrum Stylus using Rust

• Lower Costs: Up to 100x cheaper than Solidity alternatives

• Passive Income: Only solution that grows your legacy automatically

• True Decentralization: No custodians, no third parties, no trust required

• Production Ready: Fully functional, tested, and deployed

Links & Resources

• Live App: https://legatum-nicdwn.vercel.app

• GitHub: https://github.com/Nicholandn22/HacksWarisanDW

• Documentation: https://legacyvault.gitbook.io/legacy-vault

Built With

License

MIT License - Open Source and Free Forever

"Don't let your crypto die with you. Let it live on, and grow, for the ones you love."