wip: block vrf validation #288

golddydev · 2025-10-24T16:16:58Z

Overview

This PR introduces a block VRF (Verifiable Random Function) validation system for Cardano blocks which is implemented as block_vrf_validator module.

Key Changes

1. Ouroboros Module Integration

Exposed the ouroboros module in the common crate, making Ouroboros protocol primitives publicly accessible
Added TPraos and Praos validation sub modules
Implemented VrfValidationErrors for all kinds of errors caused by VRF
Added overlay_schedule utilities to check blocks which are produced by genesis keys

2. Epoch Nonces Messaging Infrastructure

Introduced EpochNoncesMessage to the CardanoMessage enum for communicating epoch nonces across the system
Added EpochNoncesPublisher module to encapsulate the logic for publishing epoch nonces to the message bus
Epoch nonces are published after the first block of each epoch

3. Enhanced Nonce Utilities

Implemented Display trait for Nonce (shows hex hash or "NeutralNonce")
Added utility methods:
- from_number(u64) - create a nonce from a number
- neutral() - create a neutral nonce
- seed_eta() - seed nonce for randomness computation
- seed_l() - seed nonce for leader computation

4. VRF Validation State Management

Added modules/block_vrf_validator/src/state.rs for managing VRF validation state
Implemented EpochSnapshots struct to manage a sliding window of three epoch snapshots (mark, set, go)

5. Improved Error Handling

Refactored ValidationError::BadVRF to encapsulate VrfValidationError
Provides more detailed and structured error information for VRF validation failures

6. Publishing Vrf Validation Status

Refactored CardanoMessage::BlockValidation(ValidationStatus) to encapsulate VrfValidationError
Added vrf_validation_publisher to block_vrf_validator module to publish Block's Vrf Validation Result with detailed error

NOTE:

I have a few blocks invalidated even they are valid, because of VrfLeaderValueTooBig.
I am looking into active_stakes and total_active_stakes.

- add test case to validate shelley's first block using validate_vrf_tpraos

…r validation error

Copilot

Pull Request Overview

This pull request adds VRF (Verifiable Random Function) validation for Cardano block headers, implementing validation for both TPraos and Praos consensus protocols. This is a significant enhancement to ensure block headers contain valid cryptographic proofs that the block producer was legitimately selected as the slot leader.

Key changes:

Introduces a new BlockVrfValidator module to validate VRF proofs in block headers
Adds support for genesis delegations to handle overlay schedule validation during the decentralization phase
Implements epoch nonces publishing to provide randomness for VRF validation

Reviewed Changes

Copilot reviewed 29 out of 30 changed files in this pull request and generated 8 comments.

Show a summary per file

File	Description
processes/omnibus/src/main.rs	Registers the new BlockVrfValidator module
processes/omnibus/Cargo.toml	Adds dependency on block_vrf_validator module
processes/omnibus/.gitignore	Ignores blocks directory (likely for testing)
modules/block_vrf_validator/*	New module implementing VRF validation logic
modules/epochs_state/*	Adds epoch nonces publishing and refactors message publishers
common/src/ouroboros/*	New VRF validation logic for TPraos and Praos protocols
common/src/genesis_values.rs	Adds genesis delegation data structures
common/src/protocol_params.rs	Adds nonce utility methods and Display trait
common/src/messages.rs	Adds EpochNoncesMessage for publishing epoch nonces

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modules/block_vrf_validator/src/state.rs

common/src/ouroboros/vrf.rs

common/src/protocol_params.rs

modules/block_vrf_validator/src/state.rs

common/src/genesis_values.rs

…set, use active stake(set) instead of go snapshot

Copilot

Pull Request Overview

Copilot reviewed 32 out of 33 changed files in this pull request and generated 6 comments.

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common/src/ouroboros/praos.rs

modules/block_vrf_validator/src/state.rs

common/src/ouroboros/overlay_schedule.rs

modules/epochs_state/src/epochs_state.rs

common/Cargo.toml

Copilot

Pull Request Overview

Copilot reviewed 32 out of 33 changed files in this pull request and generated 4 comments.

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modules/epochs_state/src/epochs_state.rs

modules/upstream_chain_fetcher/src/utils.rs

common/src/genesis_values.rs

whankinsiv

Looks good overall! I think we should consider moving this logic into the consensus module. Also could you please break up future PRs into smaller sections? Its quite difficult to do a thorough review with this much non trivial code.

Cargo.toml

whankinsiv · 2025-10-31T21:21:23Z

common/Cargo.toml

+pallas = { workspace = true }
+pallas-math = { workspace = true }


Lets try to keep pallas limited to specific modules which need it.

whankinsiv · 2025-10-31T21:24:48Z

common/src/genesis_values.rs

 const MAINNET_SHELLEY_GENESIS_HASH: &str =
    "1a3be38bcbb7911969283716ad7aa550250226b76a61fc51cc9a9a35d9276d81";

+pub type GenesisKey = Hash<28>;


Matt recently added GenesisKeyhash and we already have GenesisDelegate in common/types.rs, please consolidate.

whankinsiv · 2025-10-31T21:27:11Z

common/src/genesis_values.rs

    pub byron_timestamp: u64,
    pub shelley_epoch: u64,
    pub shelley_epoch_len: u64,
    pub shelley_genesis_hash: [u8; 32],


This should be GenesisKeyhash type.

whankinsiv · 2025-10-31T21:29:45Z

common/src/messages.rs

    EpochActivity(EpochActivityMessage), // Total fees and VRF keys for an epoch
-    DRepState(DRepStateMessage),       // Active DReps at epoch end
-    SPOState(SPOStateMessage),         // Active SPOs at epoch end
+    EpochNonce(EpochNonceMessage), // Epoch Nonce for Epoch N (published after the first block of Epoch N)


This message isn't needed.

whankinsiv · 2025-11-03T23:52:28Z

modules/block_vrf_validator/src/snapshot.rs

+#[derive(Debug, Default)]
+pub struct Snapshot {
+    /// Map of pool_id to its vrf_key_hash
+    pub active_spos: HashMap<KeyHash, KeyHash>,


I would prefer HashMap<PoolId, VRFKeyHash>.

whankinsiv · 2025-11-03T23:54:19Z

modules/block_vrf_validator/src/state.rs

+pub struct EpochSnapshots {
+    pub mark: Arc<Snapshot>,
+    pub set: Arc<Snapshot>,
+    pub go: Arc<Snapshot>,
+}


Do we need the mark and set snapshots here or only the current snapshot?

whankinsiv · 2025-11-03T23:55:44Z

modules/block_vrf_validator/src/state.rs

+    pub shelley_params: Option<ShelleyParams>,
+
+    /// protocol parameter for Praos and TPraos
+    pub praos_params: Option<PraosParams>,


instead of storing the entire era's parameters we should probably only store the specific parameters this module needs access to such as decentralization param.

whankinsiv · 2025-11-03T23:57:49Z

modules/block_vrf_validator/src/vrf_validation_publisher.rs

+        Self { context, topic }
+    }
+
+    /// Publish the SPDD


Left over comment here.

whankinsiv · 2025-11-03T23:58:41Z

modules/block_vrf_validator/Cargo.toml

+tracing = { workspace = true }
+serde_json = { workspace = true }
+serde = { workspace = true }
+pallas = { workspace = true }


What specifically from pallas do we need in this module?

golddydev added 15 commits October 21, 2025 11:26

feat: add empty block vrf validator module

584f4a0

Merge branch 'main' into golddydev/vrf-validation

70b3eb4

refactor: change module name

ec6e5bf

fix: move assert_header

c130403

fix: merge conflicts

28f7f5d

wip: add tpraos vrf proof validadtion step

6231c47

Merge branch 'main' into golddydev/vrf-validation

6119aca

refactor: move ouroboros to common

5fa68e9

refactor: vrf validation errors

9d7b9fe

refactor: restructure ouroboros tpraos validation logic

570414d

- add test case to validate shelley's first block using validate_vrf_tpraos

Merge branch 'main' into golddydev/vrf-validation

cb25214

feat: add stake threshold check

c2880e5

revert: omnibus

6c0124d

refactor: read epoch nonce in block vrf validator and update types fo…

9bec09a

…r validation error

refactor: add validation for non obft slots

46b3501

golddydev added 4 commits October 28, 2025 14:05

chore: add spo state subscription

2475252

Merge branch 'main' into golddydev/vrf-validation

fe41c0f

feat: implement snapshot state for vrf validation

3cdc3c4

fix: cargo fmt

0a07b2c

golddydev requested a review from Copilot October 29, 2025 13:20

Copilot AI reviewed Oct 29, 2025

View reviewed changes

golddydev added 4 commits October 29, 2025 14:49

fix: typo

4fec204

chore: simplify is_tpraos bool check

0cba1a7

feat: add vrf validation publisher

a64ae1f

chore: remove unused var

91c7a87

golddydev added 5 commits October 29, 2025 16:35

refactor: publish only active epoch nonce

f591f6f

refactor: check block info sync in vrf validator

7d3d5ee

refactor: epoch nonce publisher to publish nonces when there are not …

d968c88

…set, use active stake(set) instead of go snapshot

refactor: add move test cases to tpraos validation

2b5dcd4

revert: git ignore file

6c148fb

golddydev marked this pull request as ready for review October 30, 2025 07:52

golddydev requested a review from Copilot October 30, 2025 07:52

Copilot AI reviewed Oct 30, 2025

View reviewed changes

golddydev added 2 commits October 30, 2025 09:18

fix: update praos vrf validation to use one vrf

d19c1d8

fix: typo

10c70c0

golddydev requested a review from Copilot October 30, 2025 08:24

Copilot AI reviewed Oct 30, 2025

View reviewed changes

modules/epochs_state/src/epochs_state.rs Show resolved Hide resolved

modules/epochs_state/src/epochs_state.rs Show resolved Hide resolved

modules/upstream_chain_fetcher/src/utils.rs Outdated Show resolved Hide resolved

common/src/genesis_values.rs Outdated Show resolved Hide resolved

Merge branch 'main' into golddydev/vrf-validation

59aa122

golddydev requested review from sandtreader and whankinsiv October 30, 2025 15:34

golddydev added 2 commits October 30, 2025 16:44

test: add praos test case

a0c0045

Merge branch 'main' into golddydev/vrf-validation

22fd669

golddydev requested a review from lowhung October 30, 2025 15:47

This was referenced Oct 31, 2025

📊 Weekly Status - Week of 2025-10-31 #331

Open

📊 Weekly Status - Week of 2025-11-03 #334

Open

whankinsiv reviewed Nov 4, 2025

View reviewed changes

golddydev added 3 commits November 5, 2025 08:02

Merge branch 'main' into golddydev/vrf-validation

9c6e29d

fix: build errors

c82b74b

fix: clippy

7604607

		pallas = { workspace = true }
		pallas-math = { workspace = true }

wip: block vrf validation #288

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wip: block vrf validation #288

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golddydev commented Oct 24, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Overview

Key Changes

1. Ouroboros Module Integration

2. Epoch Nonces Messaging Infrastructure

3. Enhanced Nonce Utilities

4. VRF Validation State Management

5. Improved Error Handling

6. Publishing Vrf Validation Status

NOTE:

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golddydev commented Oct 24, 2025 •

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