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Features

Privacy

Private Validium is a deployment model for Lineth (formerly the Linea Stack) that keeps transaction data offchain while maintaining cryptographic guarantees through zk-SNARK proofs. It is designed for regulated financial institutions and applications requiring privacy, compliance controls, and selective data disclosure.

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Reach out to enquire about rollup-as-a-service, wherein all or part of the operations are supported by Linea and its partners.

Validium differentiators​

In validium mode, the Lineth deployment proves state transitions using zk-SNARKs while retaining transaction data within a private data availability layer. After blocks are produced by the sequencer, they are aggregated and batched, and a zk-SNARK proof attesting to the resulting state transition is generated and submitted to the finalization layer.

Key features​

Offchain data availability​

Transaction data is stored offchain in a private node set, so only state commitments and zk-SNARK proofs go onchain. This keeps transactions private, but it also means you can reconstruct or independently verify history only if you have access to the offchain data, which the deployment's role-based access control (RBAC) and governance rules control.

With the relevant data, a participant can verify their own state against the onchain commitments using Merkle proofs. Unlike a public network, a validium does not give every participant a full view of all transactions or their ordering.

Role-based access control​

RBAC controls access to network functionality:

  • RPC endpoints: Access controlled by API keys and permissions
  • API portal: Institution-level access controls
  • Transaction visibility: Participants see only transactions they're authorized to view

Privacy and compliance​

Private Validium supports regulated financial applications:

  • Transaction privacy: Transaction details not visible on finalization layer
  • Selective disclosure: Authorized parties (auditors, regulators) can access transaction data
  • Compliance controls: Compliance checks can be enforced at the API and sequencer levels
  • Audit trails: Complete audit trails while maintaining privacy

API portal​

The API portal provides controlled access to network functionality:

  • Institution onboarding and management
  • Token issuance and management
  • Settlement workflows (CBP, PVP, DVP)
  • Balance queries and reporting

Finalization layer options​

Private Validium can finalize on:

  • Ethereum L1: direct finalization on Ethereum with higher costs and longer finality times
  • Linea Mainnet: finalization on Linea Mainnet with lower costs and faster finality

See a comparison of finalization layer options.

Use cases​

Private Validium is ideal for:

  • Regulated financial institutions: Banks, payment processors, and financial market infrastructures requiring compliance and privacy
  • Multi-party workflows: Applications where participants should not see all transaction details
  • Tokenized assets: Issuance and settlement of tokenized securities and cash
  • Cross-border payments: Settlement systems requiring privacy and compliance controls

Architecture​

Private Validium deployments include:

  • Consensus layer: Maru with Quorum-Based Byzantine Fault Tolerance (QBFT) consensus (minimum 4 nodes, see distributed sequencing)
  • Execution layer: Linea Besu with sequencer plugins
  • Coordinator: Orchestrates proof generation and finalization
  • Prover: Generates zk-SNARK proofs
  • State manager: Maintains state for proof generation
  • Private RPC nodes: RBAC-protected RPC endpoints
  • API portal: Controlled access to network functionality
  • Data availability: Private node set for data storage

Security and trust​

Trust assumptions​

Private Validium requires trust in:

  • Data availability providers: Must make data available when needed
  • Validator set: Must follow consensus protocol (QBFT provides fault tolerance)
  • Finalization layer: Inherits the security of the selected finalization layer

Security features​

  • Minimum node count: 4 nodes for QBFT fault tolerance
  • Access controls: RBAC on RPC and API endpoints
  • Key management: Supports Web3Signer remote signing backed by a hardware security module (HSM) or key management service (KMS)
  • Network isolation: Private network topology

Data availability​

Where deployments use a private node set for data storage, participants must trust that data availability providers will make data available when needed, or operate under a consortium model that gives them direct access to the data required for verification and recovery.

Next steps​

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