Cadence

📌 Project Overview & Tagline

Cadence Protocol is a self-custodial, zero-leak digital inheritance and estate planning protocol built for the next generation of retail investors. It replaces fragile dead man's switches and centralized custodial trusts with a multi-signal Proof-of-Life consensus engine, client-side ECIES encryption, and autonomous yield-bearing distribution streams (Cadence Streams) powered by Aave v3 and regulated stablecoins (Paxos USDG).

• Live dApp: https://cadence-ebon-six.vercel.app/

• Core Deployments: Arbitrum Sepolia (421614), Robinhood Chain Testnet (46630), Ethereum Sepolia (11155111)

🚨 The Problem: Over $100 Billion in Trapped Wealth

The fundamental tenet of Web3 "not your keys, not your coins" creates a catastrophic blindspot: when a self-custodial asset holder passes away or is incapacitated, their digital wealth dies with them. Today, digital asset holders face two flawed alternatives:

1. The Centralized Custodial Trap: Legacy trusts or exchange custodians require surrendering private keys to third parties, destroying self-sovereignty, charging exorbitant probate/management fees, introducing institutional bankruptcy risk, and exposing families through invasive KYC.

2. The Naive On-Chain "Guillotine" Switch: Existing decentralized dead man's switches suffer from three critical flaws:

   • Zero Privacy: Storing heir addresses and allocation percentages in plaintext public storage slots exposes family net worth to anyone inspecting contract storage.

   • False Liquidations: Brittle countdown timers lack nuance. Hospitalization, travel, or a lost device can trigger premature, irreversible asset distribution.

   • The Lump-Sum "Inheritance Dump" & Drainer Risk: Dumping 100% of an estate into an heir's wallet in a single transaction makes grieving families immediate targets for phishing drainers, while idle capital sits earning 0% yield.

💡 The Solution: Cadence Protocol

Cadence solves estate transfer on-chain with institutional-grade security and consumer-friendly UX:

1. Multi-Signal Proof-of-Life Consensus Engine

Instead of relying on a single brittle timer or third-party death certificates, Cadence combines:

• Heartbeat Telemetry: Periodic owner check-ins via standard transactions or gasless ERC-4337 paymasters.

• 2-of-3 Guardian Quorum: Trusted contacts attest on-chain to trigger the inheritance sequence, backed by non-custodial backup guardian nomination.

• 72-Hour Contest Window: Provides an unforgeable grace period for living owners to contest accidental or malicious claims.

2. Cadence Streams: Autonomous Yield-Bearing Vesting

• No Lump-Sum Dump: Upon activation, heirs receive an immediate emergency buffer (e.g., 10%) while the remaining 90% is streamed linearly per second over an agreed horizon (e.g., months or years).

• Live Lending Yield (Never Staked): Unvested assets are deposited directly into Aave v3 liquidity pools on Arbitrum Sepolia to earn borrower-paid interest, or into Paxos USDG vaults pegged to live yield. Capital works for the family continuously rather than sitting idle.

• Anti-Drainer Circuit Breaker: If an heir’s wallet is compromised by a drainer bot, guardians or pre-registered backup addresses can call pauseStream() and redirectStream() to immediately halt outflows and re-route unvested assets to a secure cold wallet.

3. Zero Plaintext On-Chain Storage

• Allocations, beneficiary addresses, and blinding salts are encrypted client-side using ECIES-secp256k1 and committed to the contract as an opaque 32-byte blinded Merkle root (allocationRoot).

• Family net worth, heir identities, and percentage splits remain completely invisible to block explorers and eth_getStorageAt queries.

4. Zero Gas-Linkage Stealth Cancellation

• If a false alarm occurs, the living owner clicks [RESET PROTOCOL: I'M ALIVE] to generate an off-chain EIP-712 typed signature.

• Gasless relayers broadcast the reset transaction on the owner's behalf with zero gas paid by the owner, preventing blockchain forensics from linking the owner’s active wallet to the estate vault.

5. Arbitrum Stylus WASM Verification

• Merkle allocation verification is implemented in Rust as an Arbitrum Stylus WASM contract (stylus_merkle), achieving sub-cent gas execution with bit-for-bit equivalence against OpenZeppelin Solidity standards.

🔄 End-to-End User Flow

1. Vault Creation (/vault/create): The benefactor deposits assets (ETH, USDG), encrypts heir allocations in browser memory, designates 2-of-3 guardians, and deploys the vault in 1 single atomic transaction via OneClickInheritanceVault.sol.

2. Telemetry & Vitality Monitoring (/dashboard): Real-time ECG rhythm telemetry displays vault health (62 BPM Steady). An off-chain Sentinel daemon monitors heartbeats and alerts the owner before check-in intervals lapse.

3. Consensus Challenge (/contest): If a check-in lapses, guardians are notified. Achieving a 2-of-3 guardian consensus moves the vault to ClaimPending and starts the 72-hour grace window.

4. Stealth Reset (If Owner is Alive): The owner signs an off-chain EIP-712 cancellation. The relayer submits it, resetting the vault to Active without owner gas expenditure.

5. Heir Claim & Streaming (/claim): After the contest period elapses, the heir connects their wallet, derives their ECIES key ephemerally in RAM via an EIP-712 signature (zero private keys typed), decrypts their allocation, verifies their Merkle proof, and unlocks the Cadence Stream.

🛠️ Technology Stack

📋 Verified Deployments

🔒 Security & Verification Metrics

• Foundry Unit & Fuzz Tests: 252 / 252 tests passing across 18 test suites (contracts/test/).

• Slither Static Analysis (v0.11.6): 0 Critical, 0 High, 0 Medium vulnerabilities across 55 contracts.

• Notification Security Regression Suite: 11 / 11 suites passing covering rate limiting, timing-safe auth, XSS, and payload schemas.

• Frontend TypeScript & ESLint: Strict compilation, 0 errors, 0 warnings.

• Dependencies: 0 vulnerabilities on npm audit.