DEHR: Decentralized Hash Registry

A Blockchain-Based Document Integrity and Provenance System

Version 1.0
May 2025

Abstract

The Decentralized Hash Registry (DEHR) is a smart contract protocol deployed on the Optimism network that provides immutable, timestamped proof of document existence and ownership. By combining cryptographic hashing with blockchain transparency, DEHR creates a decentralized notarization system that links document integrity to verified registrant identities. This whitepaper outlines the technical architecture, security model, and practical applications of DEHR as a foundational infrastructure for digital document attestation.

1. Introduction

1.1 Problem Statement

Traditional document verification systems suffer from several critical limitations:

Centralized Control: Reliance on trusted third parties creates single points of failure
Lack of Transparency: Verification processes are often opaque and non-auditable
High Costs: Traditional notarization and verification services incur significant fees
Limited Accessibility: Geographic and temporal constraints restrict access to verification services
Identity Dissociation: Document proofs lack verifiable links to registrant identities

1.2 Solution Overview

DEHR addresses these challenges through a decentralized registry that:

Provides immutable proof of existence for any digital document
Links registrations to verified registrant identities through wallet registration
Operates transparently on public blockchain infrastructure
Eliminates intermediaries while maintaining cryptographic security
Offers global accessibility with 24/7 availability

2. Technical Architecture

2.1 Core Components

2.1.1 Registrant Management System

DEHR implements a two-tier registration model:

struct Registrant {
    string name;
    uint256 registrationTimestamp;
    bool isActive;
}

mapping(address => Registrant) private registrants;

Wallet Registration Requirements:

Unique registrant name (non-empty string)
One-time registration per wallet address
Immutable association between wallet and registrant identity

2.1.2 Hash Registry Core

The registry maps SHA-256 file hashes to comprehensive registration metadata:

struct Registration {
    address registrant;
    string registrantName;
    string filename;
    uint256 timestamp;
}

mapping(bytes32 => Registration) private registry;

2.2 State Management

DEHR maintains several data structures for efficient querying:

Primary Registry: Hash-to-registration mapping
User Enumeration: Per-user hash collections for portfolio management
Global Enumeration: Complete hash inventory for ecosystem analytics

2.3 Event Architecture

The contract emits structured events for off-chain indexing and real-time monitoring:

event HashRegistered(
    bytes32 indexed fileHash,
    address indexed registrant,
    string indexed registrantName,
    string filename,
    uint256 timestamp
);

event RegistrantRegistered(
    address indexed wallet,
    string indexed registrantName,
    uint256 timestamp
);

3. Security Model

3.1 Access Control

DEHR implements a permissioned registration model where:

Only registered wallets can register document hashes
Wallet registration is a prerequisite for all hash operations
Each wallet maintains a unique, immutable registrant identity

3.2 Attack Vector Mitigation

3.2.1 Reentrancy Protection

All state-changing functions utilize OpenZeppelin's ReentrancyGuard:

function registerHash(
    bytes32 fileHash,
    string calldata filename
) external nonReentrant onlyRegisteredWallet {
    // Protected state changes
}

3.2.2 Input Validation

Comprehensive validation prevents malformed registrations:

Hash Validation: Rejects zero hashes (bytes32(0))
Filename Validation: Requires non-empty filename strings
Duplicate Prevention: Blocks re-registration of existing hashes
Name Validation: Ensures registrant names are non-empty

3.2.3 Immutability Guarantees

Once registered, hash-to-registrant associations are permanent and cannot be modified, ensuring data integrity over time.

4. Operational Workflows

4.1 Registrant Onboarding

sequenceDiagram
    participant User as User Wallet
    participant DEHR as DEHR Contract
    
    User->>DEHR: registerWallet("John Doe")
    DEHR->>DEHR: Validate name & wallet status
    DEHR->>DEHR: Store registrant mapping
    DEHR->>User: Emit RegistrantRegistered event

4.2 Document Hash Registration

sequenceDiagram
    participant User as Registered User
    participant DEHR as DEHR Contract
    
    User->>User: Generate SHA-256 hash off-chain
    User->>DEHR: registerHash(hash, "document.pdf")
    DEHR->>DEHR: Verify wallet registration
    DEHR->>DEHR: Validate hash uniqueness
    DEHR->>DEHR: Store registration with timestamp
    DEHR->>User: Emit HashRegistered event

4.3 Verification Process

sequenceDiagram
    participant Verifier as Anyone
    participant DEHR as DEHR Contract
    
    Verifier->>DEHR: isRegistered(hash)
    DEHR->>Verifier: Returns boolean
    Verifier->>DEHR: getRegistration(hash)
    DEHR->>Verifier: Returns (registrant, name, filename, timestamp)

5. Gas Optimization

5.1 Optimism Layer 2 Benefits

Deployment on Optimism provides:

Reduced Gas Costs: ~10-100x lower than Ethereum mainnet
Faster Confirmations: Sub-second transaction finality
Ethereum Security: Inherits Ethereum's battle-tested security model

5.2 Efficient Data Structures

Packed Structs: Optimized storage layout minimizes storage slots
Minimal State Changes: Single storage write per registration
Event-Driven Architecture: Heavy data stored in events, not state

6. Integration Patterns

6.1 Frontend Integration (Signether)

DEHR integrates seamlessly with the Signether web application:

// Wallet registration
await dehrContract.registerWallet(registrantName);

// Hash registration
const fileHash = await generateSHA256(file);
await dehrContract.registerHash(fileHash, file.name);

// Verification
const registration = await dehrContract.getRegistration(fileHash);

6.2 API Integration

Standard Web3 libraries provide direct contract interaction:

const { ethers } = require('ethers');

const provider = new ethers.providers.JsonRpcProvider('https://mainnet.optimism.io');
const contract = new ethers.Contract(contractAddress, abi, provider);

// Query operations
const isRegistered = await contract.isRegistered(fileHash);
const registration = await contract.getRegistration(fileHash);

7. Economic Model

7.1 Cost Structure

DEHR operates on a pay-per-use model with transparent pricing:

Wallet Registration: ~$0.01-0.10 USD (one-time)
Hash Registration: ~$0.001-0.01 USD per document
Verification: Free (read operations)

7.2 Value Proposition

Cost Efficiency: 99%+ cost reduction vs. traditional notarization
Global Scale: No geographic limitations or business hours
Permanent Availability: 24/7 verification capability
Cryptographic Integrity: Mathematical proof of document authenticity

8. Use Cases

8.1 Legal Documentation

Contract Execution: Timestamped proof of agreement versions
Intellectual Property: Prior art establishment for patents/copyrights
Compliance Records: Regulatory filing verification

8.2 Academic & Research

Thesis Defense: Submission timestamp verification
Research Data: Dataset integrity and provenance tracking
Publication Priority: Establish research priority claims

8.3 Business Operations

Version Control: Document revision tracking
Audit Trails: Compliance documentation
Supply Chain: Certificate of authenticity verification

8.4 Personal Documentation

Identity Documents: Backup verification for important papers
Medical Records: Health document integrity
Financial Records: Tax document verification

9. Security Considerations

9.1 Threat Model

Mitigated Threats:

Document tampering (cryptographic hashing)
Registration forgery (wallet-based authentication)
Timestamp manipulation (blockchain consensus)
Centralized censorship (decentralized infrastructure)

Residual Risks:

Private key compromise (user responsibility)
Off-chain document availability (orthogonal concern)
Quantum computing (future cryptographic concern)

9.2 Best Practices

Key Management: Users must secure private keys properly
Hash Verification: Always verify document hashes before registration
Network Verification: Confirm correct Optimism network connection
Backup Storage: Maintain secure document copies independently

10. Future Developments

10.1 Protocol Enhancements

Multi-Hash Support: SHA-3, BLAKE2 algorithm compatibility
Batch Registration: Gas-efficient bulk document processing
Metadata Extensions: Enhanced document categorization
Cross-Chain Compatibility: Multi-network registration support

10.2 Ecosystem Integration

IPFS Integration: Decentralized document storage linking
ENS Support: Human-readable registrant naming
Oracle Integration: Real-world event triggering
Layer 3 Deployment: Application-specific blockchain optimization

11. Conclusion

The Decentralized Hash Registry represents a paradigm shift toward trustless document verification infrastructure. By combining cryptographic integrity with blockchain transparency, DEHR creates a globally accessible, cost-effective alternative to traditional notarization services.

The protocol's dual-registration model (wallets + hashes) provides verifiable identity linkage while maintaining user privacy and system security. Deployment on Optimism ensures economic viability while preserving the security guarantees of Ethereum's consensus mechanism.

As digital transformation accelerates across industries, DEHR provides the foundational infrastructure for next-generation document attestation systems, enabling new business models built on cryptographic proof rather than institutional trust.

Technical Specifications

Contract Address: TBD (Optimism Mainnet)
Compiler Version: Solidity ^0.8.28
Dependencies: OpenZeppelin Contracts v5.0+
Network: Optimism (Layer 2)
License: MIT

References

Nakamoto, S. (2008). Bitcoin: A Peer-to-Peer Electronic Cash System
Buterin, V. (2014). Ethereum Whitepaper
Optimism Collective. (2021). Optimistic Rollup Protocol Specification
OpenZeppelin. (2024). Smart Contract Security Patterns
NIST. (2015). SHA-256 Cryptographic Hash Algorithm Standard

For technical support and implementation guidance, visit the Signether Documentation or contact the development team.

Name		Name	Last commit message	Last commit date
Latest commit History 2 Commits
README.md		README.md

Signether/Whitepaper

Folders and files

Latest commit

History

Repository files navigation