Committee aggregation #282

kamilsa · 2026-01-14T12:38:27Z

🗒️ Description

Introduces aggregator role and subnet aggregation.

Every validator is assigned to one of the attestation subnets
New role: aggregator. Any validator could become an aggregator.
Aggregators collect signatures that correspond to validators from their subnet
* If aggregators collected 90% of signatures from their subnet by the beginning of slot 2, they produce aggregated attestation and propagate it into aggregation topic
Validators subscribe to aggregation topic, so that next block proposer may include committee aggregations into the block (without recursive aggregation for now)
There are five 3SF intervals now (each 800ms):
- Interval 0: block proposal
- Interval 1: validators vote and gossip their vote to their attestation subnet
- Interval 2: aggregators use collected votes, aggregate them into aggregated attestation, and broadcast to aggregation topic
- Interval 3: validators update their safe target based on received aggregated attestations for the current slot
- Interval 4: validators accept aggregated attestations and move them to known aggregated attestations, so that they are used in fork choice by the next proposer
latest_new_attestations and latest_known_attestations were replaced with latest_new_aggregated_payloads and latest_known_aggregated_payloads
Some tests became irrelevant and got removed

🔗 Related Issues or PRs

leanEthereum/pm#56
leanEthereum/pm#58

✅ Checklist

Ran tox checks to avoid unnecessary CI fails:
```
uvx tox
```
Considered adding appropriate tests for the changes
Considered updating the online docs in the ./docs/ directory.

use committee aggregated signature proofs

also rename gossip_signatures to gossip_committee_signatures

jihoonsong

Great work! Please excuse leaving some comments while it's still in draft. Just wanted to help iterate faster :)

docs/client/validator.md

jihoonsong · 2026-01-14T15:25:40Z

src/lean_spec/subspecs/containers/state/state.py

        # Configure the genesis state.
        genesis_config = Config(
            genesis_time=genesis_time,
+            attestation_subnet_count=AGGREGATION_COMMITTEE_COUNT,


I admit that I was the one who advocated for attestation committee, but based on the fact that validators only push their attestations to aggregators in their subnet without subscribing to it, I now think aggregation committee gives us slightly better description.

I don't mind whichever we choose—either attestation committee or aggregation committee—but I do think we need to stick to one thing consistently in the Lean spec and pq-devnet-3.md in the pm repo.

I don't have a strong preference too, however I think the rationale for topic names in beacon chain spec is based on the type of messages that are being propagated to this topic. For consistency we should probably stick to the same logic and keep using attestation subnets and attestation committees

Sounds great! In the same vein, what do you think about this one?

looks good to me, applied your suggestion

src/lean_spec/subspecs/forkchoice/store.py

…ted references

# Conflicts: # src/lean_spec/subspecs/forkchoice/store.py # src/lean_spec/subspecs/networking/__init__.py

src/lean_spec/subspecs/networking/gossipsub/topic.py

docs/client/validator.md

jihoonsong · 2026-01-15T11:42:53Z

docs/client/validator.md

-
-When aggregation is added, aggregators will collect attestations and combine them.
-Aggregated attestations will be broadcast separately.
+Devnet-2 introduces signatures aggregation. Aggregators will collect attestations and combine them. Aggregated attestations will be broadcast separately.


Suggested change

Devnet-2 introduces signatures aggregation. Aggregators will collect attestations and combine them. Aggregated attestations will be broadcast separately.

Devnet-3 introduces signatures aggregation. Aggregators will collect attestations and combine them. Aggregated attestations will be broadcast separately.

…nt in configuration

Aggregate during interval 2 if more threshold signatures were received

g11tech · 2026-01-21T09:45:54Z

docs/client/validator.md

+
+In the devnet-3 design, however, there is one global subnet for signed 
+attestations propagation, in addition to publishing into per committee subnets.
+This is due to 3SF-mini consensus design, that requires 2/3+ of all 


this global bit is not required, once the aggregtors publish signed attestations in the 2nd interval, they can be imported by all validators in the 3rd interval

Unfortunately, without global topic for attestations, we might not be able to receive proofs in time to update safe target during interval 2:

Interval 0: block propagation

Interval 1: votes propagation

Interval 2: signatures aggregation (up to one second for 1000 validators in subnet with 1000sigs/second expected sigs aggregation rate) + proof distribution => No time for updating safe target => in next slot validator votes for old target

src/lean_spec/subspecs/chain/config.py

g11tech · 2026-01-21T10:20:53Z

src/lean_spec/subspecs/containers/attestation/attestation.py

            for data, validator_ids in data_to_validator_ids.items()
        ]
+
+class SignedAggregatedAttestation(Container):


@anshalshukla / @GrapeBaBa do we already have this type?

also better to use message, signature terminlogy

I think we also need aggregated bit vector here as well,

I think we also need aggregated bit vector here as well,

AggregatedSignatureProof contains AggregationBits

@anshalshukla / @GrapeBaBa do we already have this type?

no

…n propagation in committee subnets

# Conflicts: # src/lean_spec/subspecs/networking/gossipsub/__init__.py # src/lean_spec/subspecs/node/node.py # tests/lean_spec/helpers/__init__.py # tests/lean_spec/subspecs/chain/test_service.py

…DS_PER_SLOT

unnawut

The diffs are very large and spread out now. I suggest we rebase and merge this asap and do incremental reviews after.

src/lean_spec/subspecs/containers/state/state.py

# Conflicts: # src/lean_spec/subspecs/containers/state/state.py # src/lean_spec/subspecs/forkchoice/store.py # src/lean_spec/subspecs/networking/gossipsub/__init__.py # src/lean_spec/subspecs/validator/service.py

Co-authored-by: Unnawut Leepaisalsuwanna <921194+unnawut@users.noreply.github.com>

…mittee-aggregation

kamilsa added 14 commits January 13, 2026 09:47

networking: update committee docs

b5b6d8a

networking: add committee size configuration

4867d7d

store committee attestations

7bcedca

Add aggregation in 2nd interval

980b5e8

Committee aggregation

60468af

Rename aggregation committee size to count for clarity

213504a

Remove committee signatures

4fac983

Refactor build_block:

f2651d8

use committee aggregated signature proofs

Clarify attestation broadcasting and update Devnet reference

cc7548c

remove adding proposer signatures to gossip_signatures

cb1a21b

also rename gossip_signatures to gossip_committee_signatures

Refactor subnet ID computation and rename committee signatures variable

e398823

Store proposer signature if same subnet

90fc114

Update build block with selecting aggregations

cdae6a4

Uncomment on_attestation during on_gossip_aggregation

b24d3ed

kamilsa mentioned this pull request Jan 14, 2026

PQ Interop #22 | Jan 14, 2026 ethereum/pm#1866

Closed

Update gossipsub topic names to reflect devnet3

5c952ff

jihoonsong reviewed Jan 14, 2026

View reviewed changes

kamilsa added 2 commits January 15, 2026 16:13

Rename aggregation committee to attestation committee and update rela…

8a0c121

…ted references

Merge remote-tracking branch 'origin/main' into committee-aggregation

cb952f8

# Conflicts: # src/lean_spec/subspecs/forkchoice/store.py # src/lean_spec/subspecs/networking/__init__.py

jihoonsong reviewed Jan 15, 2026

View reviewed changes

kamilsa added 6 commits January 15, 2026 19:59

refactor: rename committee aggregation topic to aggregated attestation

9d721bd

update validator.md to clarify subnet usage in attestation committees

baddbeb

feat: add threshold ratio for committee signature aggregation

6556e81

feat: replace attestation_subnet_count with attestation_committee_cou…

3477d6e

…nt in configuration

feat: add committee signature threshold ratio chain config

9174f5b

feat: aggregate on gossip

3115ef5

Aggregate during interval 2 if more threshold signatures were received

g11tech reviewed Jan 21, 2026

View reviewed changes

src/lean_spec/subspecs/chain/config.py Outdated Show resolved Hide resolved

g11tech reviewed Jan 21, 2026

View reviewed changes

docs: clarify aggregator role in validator participation

3fffe71

kamilsa added 14 commits January 30, 2026 14:50

Use milliseconds instead of seconds for slot and interval calculations

ac9b2e3

Introduce 5 intervals

73429c6

Refactor attestation processing to utilize aggregated payloads

5fd7e0b

Fix/remove tests

113e136

Refactor networking and validator documentation to clarify attestatio…

0616107

…n propagation in committee subnets

Remove compute_aggregated_signatures

5cabfbd

Make uvx tox pass

e39b042

Merge remote-tracking branch 'origin/main' into committee-aggregation

0ec04f1

# Conflicts: # src/lean_spec/subspecs/networking/gossipsub/__init__.py # src/lean_spec/subspecs/node/node.py # tests/lean_spec/helpers/__init__.py # tests/lean_spec/subspecs/chain/test_service.py

Merge fixes

4bd283c

Fix tests

7d1e0f2

Self review + some comment fixes

3a06ccd

Update comment

1943eda

Shorten comment

9f3e05b

Refactor time constants to use SECONDS_PER_SLOT instead of MILLISECON…

ed02f93

…DS_PER_SLOT

Kayden-ML mentioned this pull request Feb 3, 2026

Implement Committee aggregation In ream ReamLabs/ream#1200

Open

unnawut approved these changes Feb 4, 2026

View reviewed changes

src/lean_spec/subspecs/containers/state/state.py Outdated Show resolved Hide resolved

kamilsa and others added 6 commits February 4, 2026 14:21

Merge remote-tracking branch 'origin/main' into committee-aggregation

583201d

# Conflicts: # src/lean_spec/subspecs/containers/state/state.py # src/lean_spec/subspecs/forkchoice/store.py # src/lean_spec/subspecs/networking/gossipsub/__init__.py # src/lean_spec/subspecs/validator/service.py

Update src/lean_spec/subspecs/containers/state/state.py

8f6c63c

Co-authored-by: Unnawut Leepaisalsuwanna <921194+unnawut@users.noreply.github.com>

Merge remote-tracking branch 'origin/main' into committee-aggregation

9a2a75f

refactor test attestation target test

d48d9c3

Merge remote-tracking branch 'kamilsa/committee-aggregation' into com…

db34a77

…mittee-aggregation

uvx tox fix

8271f78

kamilsa mentioned this pull request Feb 5, 2026

Fix interop tests after #282 #359

Open

skip failing interop tests in late joiner and multi-node test files

6c94cd6

kamilsa mentioned this pull request Feb 5, 2026

Return actual milliseconds clock #360

Closed

kamilsa added 2 commits February 5, 2026 14:47

add TODO to return actual milliseconds in _milliseconds_since_genesis

4ddaccd

add TODO to consider pruning old entries in aggregated payloads

72a6f78

tcoratger approved these changes Feb 5, 2026

View reviewed changes

tcoratger merged commit 98bb791 into leanEthereum:main Feb 5, 2026
11 checks passed

bomanaps mentioned this pull request Feb 6, 2026

Add aggregator gossip path unit and integration tests #367

Open

3 tasks

	Devnet-2 introduces signatures aggregation. Aggregators will collect attestations and combine them. Aggregated attestations will be broadcast separately.
	Devnet-3 introduces signatures aggregation. Aggregators will collect attestations and combine them. Aggregated attestations will be broadcast separately.

Committee aggregation #282

Committee aggregation #282

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kamilsa commented Jan 14, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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🗒️ Description

🔗 Related Issues or PRs

✅ Checklist

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kamilsa commented Jan 14, 2026 •

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