Miden Validator

The Miden Validator is a temporary component of the Miden node that provides transaction validation and block signing services for the Miden network. It is a core component of the network's "guardrails" that provide additional validation and assurances while the protocol is in active development.

Overview

The validator component is responsible for:

• Transaction Validation: Receiving and re-executing proven transactions from the RPC layer.
• Transaction Storage: Persisting re-executed transaction data for block verification and signing.
• Block Validation: Verifying blocks produced by the block producer using stored transaction information.
• Block Signing: Cryptographically signing valid blocks as part of the consensus process.

Architecture

The validator operates as a gRPC server and integrates with other Miden node components according to the following flow:

sequenceDiagram
    participant Client
    participant RPC
    participant Validator
    participant BlockProducer as Block Producer
    participant Store
    participant RemoteProver as Remote Prover

    Note over Client, Validator: Transaction Submission
    Client->>RPC: SubmitProvenTransaction()

    Note over RPC, Validator: Transaction Validation

    RPC->>RPC: Validate transaction
    RPC->>Validator: Submit transaction
    Validator->>Validator: Validate transaction
    Validator->>Validator: Store transaction
    Validator->>RPC: Accepted
    RPC->>Client: OK


    Note over BlockProducer, RPC: Block Building
    RPC->>BlockProducer: Forward valid transaction
    BlockProducer->>BlockProducer: Build proposed block

    Note over BlockProducer, Validator: Block Validation
    BlockProducer->>Validator: Proposed block
    Validator->>Validator: Check block validity using stored tx info
    Validator->>BlockProducer: Signed block header
    BlockProducer->>BlockProducer: Signed Block
    BlockProducer->>Store: Signed block

    Note over Store, RemoteProver: Block Proving
    Store->>RemoteProver: Signed block
    RemoteProver->>Store: Block proof
    Store->>Store: Proven block

Current Status

[!WARNING] The validator is currently a work in progress and under active development. Many features described above are not yet fully implemented.

Implemented Features

• ✅ Protobuf schema and gRPC server scaffolding.
• ✅ Transaction submission handler.

In Development

• 🚧 Transaction re-execution logic.
• 🚧 Database schema and impl.
• 🚧 Block validation logic.
• 🚧 Block signing logic.
• 🚧 Integration with RPC.
• 🚧 Integration with block producer consensus.

API

The validator exposes a gRPC API with the following endpoints:

• Status() - Returns validator health and version information.
• SubmitProvenTransaction() - Validates and stores a proven transaction.
• ValidateBlock() - Validates a block and returns a signature (TODO).

Configuration

The validator requires:

• Address: Network address for the gRPC server.
• gRPC Timeout: Request timeout duration.
• Data Directory: Path for SQLite database files.

License

This project is MIT licensed.