Zelf Legacy: Biometric Inheritance Protocol for Base Chain
Requested Budget: $50,000 USD equivalent on Base
Organization: Zelf World LLC (Wyoming, USA)
Abstract
Zelf Legacy introduces a non-custodial inheritance infrastructure for digital assets built on Base and solidity.
Users can maintain multiple self-custody wallets across trading, savings, and on-chain applications while ensuring that, in the event of post-mortem or prolonged inactivity, rightful beneficiaries can securely recover access rights without transferring assets into custody.
Instead of locking funds inside smart contracts, Zelf Legacy coordinates inheritance through programmable access-rights verification. Instead of restricting recovery to traditional seed-phrase reconstruction, Zelf Legacy coordinates on-chain recovery by triggering signature-threshold transitions or executing smart contract ownership transfers natively aligned with ERC-4337 account abstraction structures.
The system combines:
- Solidity smart contracts
- Heartbeat Protocol liveness verification
- Guardian Oracle coordination
- ZELF ID biometric identity infrastructure
- Shamir's Secret Sharing recovery architecture
No biometric templates are stored on centralized servers or databases. Assets remain in the original wallet throughout the inheritance lifecycle.
Zelf Legacy is powered by HumanAuthn, a biometric-rooted authentication and encryption primitive that regenerates ephemeral cryptographic keys from live facial verification. This architecture enables passwordless self-custody without exposing seed phrases or relying on custodial infrastructure.
The requested $50,000 grant will fund the development of:
- Solidity inheritance contracts
- Heartbeat Protocol infrastructure
- Guardian Oracle execution layer
- Base-native SDKs
- Developer tooling
- Testnet and mainnet deployment
All Base-specific infrastructure will be built natively for Solidity and open-sourced under MIT licensing.
Why This Matters for the Base Chain Ecosystem
Base Chain secures billions of dollars in self-custodied digital assets across DeFi, trading, stablecoins, and on-chain applications, yet the ecosystem lacks native inheritance infrastructure.
Without programmable inheritance mechanisms:
- assets can become permanently inaccessible
- families may lose access to funds
- long-term self-custody adoption becomes harder for mainstream users
Zelf Legacy introduces a non-custodial inheritance coordination layer designed specifically for the Base Chain ecosystem.
The protocol expands Base Chain's capabilities beyond trading and DeFi into:
- long-term digital asset continuity
- rightful ownership transfer
- programmable beneficiary coordination
- human-rooted self-custody infrastructure
This positions Base not only as an ultra-efficient, Ethereum-secured Layer 2 environment, but also as the primary foundational infrastructure for generational digital asset ownership.
What Is Zelf?
Zelf is a cybersecurity and self-custody infrastructure platform powered by HumanAuthn, a biometric-rooted authentication and encryption primitive.
Unlike traditional authentication systems that anchor trust in hardware devices or custodial databases, HumanAuthn replaces device-rooted authentication with biometric-rooted cryptographic ephemeral key regeneration.
A live biometric scan regenerates a temporary encryption key used to decrypt wallet credentials, eliminating the need for:
- seed phrases
- password storage
- custodial recovery systems
- persistent biometric templates
This creates a device-agnostic identity layer designed for self-custody, authentication, and secure digital inheritance.
Zelf is available on: Web Extension, iOS, and Android.
What Is Zelf Legacy?
Zelf Legacy addresses one of the largest unresolved problems in self-custody:
What happens to digital assets when their owner dies or becomes permanently inactive?
Most crypto inheritance systems rely on:
- custodial escrow
- multisig dependency
- smart-contract fund locking, or
- manual legal coordination
Zelf Legacy introduces a different model. Instead of transferring assets into custody, the protocol coordinates inheritance through programmable access-rights activation.
Inheritance execution only begins after:
- inactivity verification
- grace-period expiration
- beneficiary biometric verification
- government-issued identity validation
Assets remain in the original wallet throughout the entire process.
Protocol Flow Diagram
Step 1: Create an Inheritance Policy
Users activate Legacy Mode inside the Zelf app and designate beneficiaries through ZELF ID biometric identity binding.
Each beneficiary is linked to an encrypted inheritance policy that defines:
- inheritance thresholds
- beneficiary consensus rules
- legal coordination preferences
- recovery conditions
The inheritance architecture combines:
- Solidity smart contracts deployed on Base Chain
- ZELF ID biometric verification
- IPFS and Arweave decentralized storage
- Shamir's Secret Sharing recovery logic
Policy metadata is encrypted and stored off-chain while Solidity records only verification state and execution logic.
Users can configure:
- 2-of-3 or 3-of-5 recovery thresholds
- lawyer participation
- direct beneficiary execution
- multi-beneficiary inheritance structures
Step 2: Heartbeat Protocol
Zelf Legacy introduces a Heartbeat Protocol: a cryptographic liveness verification system anchored to Base smart contracts.
Instead of continuously tracking users or relying on custodial inactivity monitoring, the protocol enables periodic proof-of-life verification directly from the Zelf app.
Each heartbeat:
- verifies live user presence
- resets the inheritance inactivity timer
- emits signed on-chain events through Base contracts
- updates the inheritance execution state
The protocol is privacy-preserving by design:
- heartbeat credentials remain private
- no public inheritance registry exists
- no behavioral tracking is required
- liveness detection prevents spoofing attacks
Users define:
- inactivity windows (30 days to 24 months)
- grace periods
- inheritance activation conditions
Heartbeat history is compressed through verifiable credential architecture and Merkle-proof validation, reducing on-chain storage requirements by 100–1000x compared to traditional state storage models.
If heartbeat expiration and grace-period thresholds are reached, the inheritance execution pipeline begins.
This transforms inheritance from a manual legal process into programmable self-custody infrastructure.
Step 3: Access Rights Recovery
Once inactivity and grace-period conditions are satisfied, beneficiaries can initiate the inheritance claim process.
Claim execution requires three verification layers:
1. Biometric Verification
A live facial scan is matched against the beneficiary's registered ZELF ID without exposing biometric templates.
2. Government Identity Verification
Beneficiaries complete identity verification through Verifik's KYC infrastructure covering 190+ countries.
3. Base Smart Contract Entitlement Verification
Base smart contracts verify inheritance eligibility and authorize access-right reconstruction.
Private keys remain off-chain throughout the process.
Access Rights Recovery
| Approach | Fund Transfer (typical approach) | Access Rights (Zelf Legacy) |
|---|---|---|
| User retains control | No. Funds locked in contract | Yes. Full control until inheritance |
| Smart contract risk | High. Funds at risk if contract is exploited | Minimal. Contract holds policies, not funds |
| DeFi composability | Broken. Locked funds can't be used | Preserved. Assets remain active |
| Yield/staking | Lost during lock period | Continues normally |
| Multi-chain assets | Requires per-chain deployment | Single policy covers cross-chain access |
| Legal enforceability | Uncertain. Code-is-law | Supported. Produces verifiable evidence for lawful off-chain execution |
Design Principles
Zelf Legacy is designed around the following principles:
- Non-custodial by default
- Assets remain in the original wallet
- No biometric templates stored
- Privacy-preserving liveness verification
- Human-rooted authentication
- Programmable inheritance execution
- Off-chain encrypted metadata
- Base-native smart contract coordination
- Long-term cost sustainability
Technical Architecture
Five coordinated layers power inheritance execution without moving assets into custody.
The HumanAuthn engine and ZELF ID infrastructure are already operational.
The Base grant focuses on building the inheritance coordination layer natively on Base Chain, including:
- inheritance registry contracts
- Heartbeat Protocol infrastructure
- Guardian Oracle coordination
- claim verification pipeline
- Base wallet integration tooling
- developer tooling
The architecture is divided into four layers:
Identity Layer
ZELF ID + HumanAuthn biometric authentication.
Liveness Layer
Heartbeat Protocol for periodic proof-of-life verification.
Storage Layer
Encrypted inheritance policies, ZELF ID packets, and recovery metadata are stored off-chain through IPFS and Arweave. Solidity records only state hashes, events, and verification logic, keeping the system scalable and cost-efficient.
Coordination Layer
Guardian Oracle monitors inactivity, grace periods, lawyer notification flows, and beneficiary claim activation.
Execution Layer
Solidity inheritance contracts enforce policy rules, claim eligibility, and access-right reconstruction.
Security & Privacy
Zelf Legacy is designed to minimize custodial risk and centralized attack surfaces.
Key security properties include:
- no biometric templates stored
- private keys remain off-chain
- encrypted off-chain metadata
- liveness verification with spoof resistance
- programmable inactivity thresholds
- decentralized storage through IPFS and Arweave
- cryptographic claim verification through Solidity
The protocol coordinates access-right recovery without taking custody of user assets.
Why Base Chain?
Zelf Legacy aligns directly with Base Chain's strengths in:
- global consumer onboarding
- deep DeFi liquidity
- sub-cent transactions
- standard-setting OP Stack architecture
Inheritance is fundamentally a long-term digital ownership problem.
Base Chain provides the transaction scalability and ecosystem reach required to support programmable inheritance infrastructure at global scale.
Key reasons for choosing Base Chain include:
- Low transaction costs: Heartbeat verification must remain economically sustainable over years or decades.
- EVM Equivalence: Provides 100% bytecode compatibility with Ethereum mainnet, allowing seamless out-of-the-box integration with established Ethereum developer tooling, frameworks, and smart contract security standards.
- High throughput: Supports scalable heartbeat verification and inheritance coordination.
- Mature wallet ecosystem: Native compatibility with Coinbase Wallet (including Coinbase Smart Wallet), MetaMask, Trust Wallet, and standard EVM developer tooling.
- Large self-custody user base: Base Chain's active DeFi and retail ecosystem creates strong demand for long-term inheritance infrastructure.
Base Chain Integration Plan
Zelf Legacy is built purposefully to leverage Base's advanced account abstraction infrastructure, low-cost EVM log emitting, and native interoperability across the broader Ethereum Superchain.
Zelf Legacy is being designed as a Base-native inheritance infrastructure built around EVM smart contracts, event-driven execution, decentralized storage, and wallet interoperability.
Rather than adapting custodial inheritance systems, the protocol leverages Base Chain's low-cost execution environment to coordinate programmable access-right recovery at scale.
Base-Specific Building Blocks
Solidity Smart Contracts
Smart contracts power:
- inheritance policy registry
- Heartbeat Protocol accumulation
- claim verification logic
- beneficiary entitlement execution
EVM Event Logs
Heartbeat updates are emitted through EVM logs rather than persistent storage writes, minimizing operational costs.
Base Chain Wallet Integration
Tranche 3 integrations include:
- Coinbase Wallet
- MetaMask
- Trust Wallet
- WalletConnect support
Decentralized Storage Layer (IPFS + Arweave)
Inheritance policy metadata, encrypted ZELF ID packets, and recovery configurations are anchored off-chain through resilient decentralized storage infrastructure to maintain low on-chain footprints.
Dual-Curve Cryptographic Compatibility
HumanAuthn verification provides full native compatibility across standard EVM cryptographic protocols. It integrates seamlessly with standard ECDSA secp256k1 signing for legacy wallet infrastructure, while leveraging Base's RIP-7212 precompile to handle hardware-secured secp256r1 (P-256) signatures. This allows the system to process secure on-chain biometrics and passkey-based smart accounts with minimal gas overhead.
What Makes This Base-Native
The protocol utilizes Base's native ecosystem scaling and cost-efficient execution pipeline to establish a seamless digital continuity layer for everyday crypto adopters.
The protocol is architected specifically around:
- EVM smart contracts
- Base Chain low-cost execution
- event-driven coordination
- EVM wallet interoperability
- Base ecosystem scalability
- decentralized storage integration
Base Integration Flow
Data flow showing exactly how Base components participate in the inheritance lifecycle:
Tranche 1: MVP — Base Inheritance Core ($15,000)
Timeline: 5 Weeks
The first tranche focuses on building the foundational inheritance infrastructure natively on Solidity.
This phase includes:
- Solidity inheritance registry contracts
- ZELF ID integration
- Heartbeat Protocol implementation
- Merkle-proof heartbeat verification
- inheritance policy coordination logic
The MVP establishes the minimum viable inheritance flow:
- Create an inheritance policy
- Register beneficiaries through ZELF ID
- Emit heartbeat liveness proofs
- Trigger simulated inheritance conditions
- Execute claim verification on Base Testnet
At the end of Tranche 1, the result will be a fully simulated end-to-end inheritance event operating on Base Testnet.
Tranche 2: Testnet — Guardian Oracle & Claim Pipeline ($15,000)
Timeline: 6 Weeks
The second tranche focuses on building the inheritance coordination and verification pipeline.
This phase introduces the Guardian Oracle, responsible for monitoring:
- inactivity thresholds
- grace periods
- lawyer notification flows
- beneficiary activation conditions
Once inheritance conditions are satisfied, the claim pipeline validates:
- beneficiary biometric verification through ZELF ID
- government-issued identity verification
- inheritance entitlement through Solidity contracts
- seed phrase reconstruction authorization
- Cryptographic key share recovery or backup owner authorization mapping (supporting both legacy seed phrase shares and ERC-4337 Account Abstraction recovery paths).
The goal of this phase is to establish a secure and programmable inheritance execution flow operating fully on Base Testnet.
Tranche 3: Mainnet — SDKs, Wallet Integration & Deployment ($20,000)
Timeline: 6 Weeks
The final tranche focuses on ecosystem integration, developer tooling, and mainnet readiness.
This phase includes:
- Base-native SDKs
- Metamask, Trust wallet and Wallet Connect integrations
- developer documentation
- demo applications
- UX-ready onboarding flows
- mainnet deployment
The objective is to deliver a production-ready inheritance infrastructure that developers, wallets, and users can integrate directly into the Base ecosystem.
At completion, Zelf Legacy will operate as a live Solidity-native inheritance protocol with open-source Base infrastructure and public developer tooling.
Open Source Commitment
All Base-specific infrastructure developed through this grant will be released under MIT licensing, including:
- Solidity smart contracts
- Heartbeat Protocol infrastructure
- Guardian Oracle interfaces
- SDKs
- demo applications
- developer documentation
The HumanAuthn and ZELF ID core architecture will remain proprietary while being exposed through developer SDKs with free-tier access for Base ecosystem developers.
Summary
A $50,000 grant enables the development of a human-rooted, decentralized inheritance infrastructure for the Base Chain ecosystem.
Built for one of the world's largest self-custody and DeFi ecosystems, Zelf Legacy introduces programmable inheritance coordination without transferring assets into custodial smart contracts.
The architecture combines:
- Solidity inheritance contracts
- Heartbeat Protocol liveness verification
- Guardian Oracle coordination
- ZELF ID biometric authentication
- Base-native SDKs
- developer tooling
- testnet and mainnet deployment
Zelf Legacy transforms inheritance from a manual legal process into programmable self-custody infrastructure while preserving user ownership and keeping assets in their original wallet throughout the entire lifecycle.