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Full Node ​

Full nodes are the core validator nodes of the OpenGradient blockchain that execute EVM transactions, maintain blockchain state, and validate all proofs and attestations generated by inference nodes and data nodes on the network. They serve as the trust layer that ensures the integrity and security of the entire network through comprehensive validation and fraud detection.

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You can find the OpenGradient block explorer at https://explorer.opengradient.ai.

Core Responsibilities ​

Full nodes perform several critical functions that maintain the security and correctness of the OpenGradient blockchain:

Block Validation and State Execution ​

Full nodes receive block headers, proofs, and attestations from the sequencer via gossip protocols. They then fetch the complete block data from the Data Availability (DA) layer to reconstruct the full block. Once retrieved, full nodes execute all transactions within the block sequentially, computing the state-transition function (STF) to update their local blockchain state.

This execution includes:

  • Standard EVM Operations: All traditional Ethereum-compatible smart contract operations
  • AI Inference Precompiles: Native AI inference calls that trigger inference nodes to execute models
  • Data Node Queries: Secure data access requests handled by data nodes
  • State Updates: Computing intermediate state roots (ISRs) between transactions to track state changes

Proof and Attestation Validation ​

Full nodes validate all cryptographic proofs and attestations generated by specialized nodes:

  • Inference Node Proofs: Verify ZKML proofs, TEE attestations, or Vanilla inference results from inference nodes to ensure correct model execution
  • Data Node Attestations: Validate TEE attestations from data nodes to guarantee secure and untampered data retrieval
  • Block Proofs: Verify block validity, transaction ordering, and state transitions

This comprehensive validation ensures that all AI inference operations and data access are cryptographically verified before being accepted into the blockchain state.

Network Propagation ​

Full nodes serve as information hubs in the OpenGradient network:

  • Block Header Gossip: Propagate validated block headers to light nodes over the P2P network, enabling light nodes to stay synchronized without downloading full blocks
  • Fraud Proof Distribution: Broadcast fraud proofs to alert the network of invalid blocks
  • State Sync: Provide state snapshots and historical data to nodes that need to catch up

Trust Minimization ​

Full nodes are the foundation of trust minimization on the OpenGradient network. Through end-to-end validation of:

  • Block Data: Verifying all transactions and state transitions
  • Cryptographic Proofs: Validating ZKML proofs and TEE attestations
  • Attestations: Confirming data node attestations and inference node results
  • State Integrity: Ensuring consistency through ISR verification

Full nodes guarantee that users and applications can trust the blockchain state without needing to run their own full node. This trust minimization is achieved through cryptographic verification rather than social trust, making the network secure and decentralized.

Interaction with Other Node Types ​

Full nodes coordinate with all other node types in the HACA architecture:

  • Inference Nodes: Receive and validate inference proofs and attestations from inference nodes executing AI models
  • Data Nodes: Validate attestations from data nodes providing secure external data access
  • Storage Nodes: Reference model Blob IDs from Walrus storage (via storage nodes) when validating inference requests
  • Light Nodes: Provide block headers and fraud proofs to light nodes for efficient synchronization

Light Nodes ​

Light nodes are a lightweight alternative to full nodes that don't execute all transactions or maintain full blockchain state. Instead, they:

  • Receive block headers from full nodes via P2P gossip
  • Verify block headers using Merkle proofs
  • Rely on full nodes for fraud proofs when invalid blocks are detected
  • Provide basic blockchain access without the computational overhead of full validation

Full nodes enable light nodes to operate securely by providing them with validated block headers and fraud proofs, allowing for efficient network participation with reduced resource requirements.

State Management ​

Full nodes maintain a complete copy of the OpenGradient blockchain state, including:

  • Account Balances: All user and contract account states
  • Smart Contract Storage: Complete storage state for all deployed contracts
  • Transaction History: Full historical record of all transactions
  • State Roots: Merkle tree roots representing the state at each block

This comprehensive state management enables full nodes to:

  • Execute transactions locally to verify state transitions
  • Provide historical data queries
  • Support state synchronization for new nodes joining the network
  • Generate fraud proofs by comparing expected vs. actual state transitions

Security Guarantees ​

Full nodes provide several critical security guarantees:

  1. Cryptographic Verification: All proofs and attestations are cryptographically verified before acceptance
  2. Fraud Detection: Invalid blocks are detected and fraud proofs are generated automatically
  3. State Consistency: ISR verification ensures state transitions are correct
  4. Decentralization: Multiple independent full nodes validate the same blocks, preventing single points of failure

These guarantees ensure that the OpenGradient network remains secure, verifiable, and trustworthy, even when incorporating specialized AI inference and data access capabilities.