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ULedgerNET Cross-Merkleization

Overview​

Cross-Merkleization is ULedgerNET's proprietary mechanism for establishing cryptographic trust between multiple independent blockchain instances. It enables verifiable cross-chain state anchoring without requiring direct chain interaction.

Concept​

The Problem​

In multi-chain environments, verifying the state of one chain from another traditionally requires:

  • Direct chain access
  • Trusted intermediaries
  • Complex bridge protocols

The ULedgerNET Solution​

Cross-Merkleization provides trustless, cryptographically verifiable proofs that can be independently validated using Zero-Knowledge Proofs.

How It Works​

Block Structure with Cross-References​

Each ULedgerNET block can contain references to other chains:

Cross-Reference Content​

A cross-reference contains sufficient information to independently verify the referenced block:

FieldDescription
BlockchainIdIdentifier of the source chain
BlockHashHash of the referenced block
HeightBlock height at time of reference
TimestampBlock timestamp
MerkleRootRoot of the source block's Merkle tree
ZK ProofZero-knowledge proof of block validity
MerkleDepthDepth of the Merkle tree
MerkleElementsMerkle proof path elements

Merkle Tree Construction​

Data Flow​

Merkle Tree Structure​

Key Properties:

  • Uses ZK-friendly MiMC hash function
  • Fixed chunk size for proof compatibility
  • Tree depth varies based on data size (2-16 levels)
  • Balanced tree structure (power of 2 leaves)

Zero-Knowledge Proof Integration​

Where ZK Proofs Are Used​

Proof System: PLONK​

ULedgerNET uses PLONK (Permutations over Lagrange-bases for Oecumenical Noninteractive arguments of Knowledge) for block proofs:

AspectDetails
CurveBLS24-315
Proof SizeConstant (~1KB)
VerificationO(1) - constant time
Trust SetupUniversal (ceremony-based)

What the Proof Verifies​

The ZK proof cryptographically attests that:

  1. ✅ The Merkle root was correctly computed from the data
  2. ✅ The block index is valid (previous + 1)
  3. ✅ At least one transaction exists in the block
  4. ✅ The Merkle proof path is valid

Cross-Chain Communication​

Broadcasting Cross-References​

Topic Structure​

Verification Process​

Validating a Cross-Reference​

Verification Inputs​

To verify a cross-reference, the verifier needs:

Public Inputs:
├── Block Index (Height)
├── Previous Block Index
├── Merkle Root
└── Merkle Proof Elements

Proof:
└── PLONK Proof (from cross-reference)

Use Cases​

1. Multi-Tenant Enterprise Deployment​

Benefits:

  • Each department has autonomy
  • Main chain provides unified audit trail
  • Cross-chain proofs enable compliance

2. Supply Chain Verification​

3. Regulatory Compliance​

Security Properties​

PropertyGuarantee
IntegrityCross-references cannot be forged without ZK proof
Non-repudiationSource chain cannot deny referenced state
IndependenceVerification requires no trust in source chain operators
EfficiencyConstant-time verification regardless of chain size

Configuration​

Cross-Merkleization is enabled through blockchain configuration:

{
  "blockchainId": "chain-a",
  "principalBlockchainId": "main-chain",
  "features": {
    "enableXMOnBlockMint": true
  }
}
SettingDescription
principalBlockchainIdID of the chain to receive cross-references
enableXMOnBlockMintEnable automatic cross-reference broadcasting

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