This commit changes the public API of the KZG library to the following high-level API:
```
- verify_kzg_proof()
- compute_aggregate_kzg_proof()
- verify_aggregate_kzg_proof()
- blob_to_kzg_commitment()
```
compared to the previous much more low-level API:
```
- compute_powers()
- matrix_lincomb()
- lincomb()
- bytes_to_bls_field()
- evaluate_polynomial_in_evaluation_form()
- verify_kzg_proof()
- compute_kzg_proof()
```
This means that all the cryptographic logic (including Fiat-Shamir) is now isolated and hidden in the KZG library and the `validator.md` file ends up being significantly simplified, only calling high-level KZG functions.
Some additional things that this commit does:
- Moves all EIP4844 cryptography into polynomial-commitments.md
- Improves the Fiat-Shamir stack by removing the need for SSZ and by introducing simple domain separators
Co-authored-by: Kevaundray Wedderburn <kevtheappdev@gmail.com>
Co-authored-by: Hsiao-Wei Wang <hsiaowei.eth@gmail.com>
Co-authored-by: Dankrad Feist <mail@dankradfeist.de>
Moving the `is_post_xxx` functions to a separate module allows `genesis`
to also use them (cyclic import from `context` prevented this before).
This allows removing `FORKS_BEFORE_ALTAIR` and `FORKS_BEFORE_BELLATRIX`
constants and adding a more general `is_post_fork` function that needs
less maintenance. This then allows definition of `with_all_phases_from`
to streamline the implementation of the `with_xxx_and_later` decorators.
Future light client protocol extensions may include data from the block
in addition to data from the state, e.g., `ExecutionPayloadHeader`.
To prepare for this, also pass the block to the corresponding functions.
In practice, blocks access is easier than historic state access, meaning
there are no practical limitations due to this change.
Future light client tests will also incorporate execution payload data.
To avoid confusion, rename the current `root` check to `beacon_root`.
Doing this now, as #3066 already requires LC test runners to update.
Currently, `test_single_merkle_proof` only supports `BeaconState` tests.
For future tests, different object classes are desirable. Update format
to allow testing other objects as well.
* Do not overload index with WithdrawalIndex and ValidatorIndex
* a few more bellatrix tests
* use function from other PR
* fix tests
* Update tests/core/pyspec/eth2spec/test/bellatrix/transition/test_transition.py
Co-authored-by: Hsiao-Wei Wang <hsiaowei.eth@gmail.com>
* refactor to reuse bellatrix transitio ntests for all transitions
Co-authored-by: Potuz <potuz@prysmaticlabs.com>
Co-authored-by: Hsiao-Wei Wang <hsiaowei.eth@gmail.com>
Replaces `process_slot_for_light_client_store` which force updates the
`LightClientStore` automatically based on `finalized_header` age with
`try_light_client_store_force_update` which may be manually called based
on use case dependent heuristics if light client sync appears stuck.
Not all use cases share the same risk profile.
Adds `create_light_client_bootstrap` and `create_light_client_update`
functions as a reference implementation for serving light client data.
This also enables a new test harness to verify that light client data
gets applied to a `LightClientStore` as expected.
- Implement all the required glue code to make things executable
- Implement a dummy KZG trusted setup
Co-authored-by: Hsiao-Wei Wang <hsiaowei.eth@gmail.com>
Introduces a new `LightClientBootstrap` structure to allow setting up a
`LightClientStore` with the initial sync committee and block header from
a user-configured trusted block root.
This leads to new cases where the `LightClientStore` is only aware of
the current but not the next sync committee. As a side effect of these
new cases, the store's `finalized_header` may now advance into the next
sync committee period before a corresponding `LightClientUpdate` with
the new sync committee is obtained, improving responsiveness.
Note that so far, `LightClientUpdate.attested_header.slot` needed to be
newer than `LightClientStore.finalized_header.slot`. However, it is now
necessary to also consider certain older updates to try and backfill the
`next_sync_committee`. The `is_better_update` helper is also updated to
improve `best_valid_update` tracking.
`LightClientUpdate` structures currently use different merkle proof root
depending on the presence of `finalized_header`. By always rooting it in
the same state (the `attested_header.state_root`), logic gets simpler.
Caveats:
- In periods of extended non-finality, `update.finalized_header` may now
be outdated by several sync committee periods. The old implementation
rejected such updates as the `next_sync_committee` in them was stale,
but the new implementation can properly handle this case.
- The `next_sync_committee` can no longer be considered finalized based
on `is_finality_update`. Instead, waiting until `finalized_header` is
in the `attested_header`'s sync committee period is now necessary.
- Because `update.finalized_header > store.finalized_header` no longer
holds (for updates with finality), an `is_better_update` helper is
added to improve `best_valid_update` tracking (in the past, finalized
updates with supermajority participation would always directly apply)
This PR builds on prior work from:
- @hwwhww at https://github.com/ethereum/consensus-specs/pull/2829
Various cleanups and minor fixes:
- Consistent terminology:
- `signed_block` -> `attested_block`
- `finalized_block_header` -> `finalized_header`
- `snapshot_period` -> `store_period`
- Use correct block in finality test (`blocks[-1]` instead of new one)
- Add `signed_block_header` func to get header from `SignedBeaconBlock`
- Remove `block_header` from `get_sync_aggregate` helper arguments
- Use `state_transition_with_full_block` as shortcut for multiple calls
- Have `finalized_header` actually be header instead of full block body
- Consistent ordering of `assert` to match structure definition
The producer of `LightClientUpdate` structures usually does not know how
far the `LightClientStore` on the client side has advanced. Updates are
currently rejected when including a redundant `next_sync_committee` not
advancing the `LightClientStore`. Behaviour is changed to allow this.
The `fork_version` field in `LightClientUpdate` can be derived from the
`update.signature_slot` value by consulting the locally configured fork
schedule. The light client already needs access to the fork schedule to
determine the `GeneralizedIndex` values used for merkle proofs, and the
memory layouts of the structures (including `LightClientUpdate`). The
`fork_version` itself is network dependent and doesn't reveal that info.
* t push base design for partial withdrawals
* moor tests
* clean up withdrawals naming
* make partial withdrawal randomized tests better
* Apply suggestions from code review
Co-authored-by: Alex Stokes <r.alex.stokes@gmail.com>
Co-authored-by: Hsiao-Wei Wang <hsiaowei.eth@gmail.com>
* fix mainnet brokn test
* name swap
* lint
Co-authored-by: Alex Stokes <r.alex.stokes@gmail.com>
Co-authored-by: Hsiao-Wei Wang <hsiaowei.eth@gmail.com>
As the sync committee signs the previous block, the situation arises at
every sync committee period boundary, that the new sync committee signs
a block in the previous sync committee period. The light client cannot
reliably detect this condition (e.g., assume that this is the case when
it is currently on the last slot of a sync committee period), because
the last couple slots of a sync committee period may not have a block.
For example, when receiving a `LightClientUpdate` that is constructed
as in the following illustration, it is unknown whether `sync_aggregate`
was signed by the current or next sync committee at `attested_header`.
```
slot N N + 1 | N + 2 (slot not sent!)
|
+-----------------+ \ / | +----------------+
| attested_header | <--- X ----|---- | sync_aggregate |
+-----------------+ / \ | +----------------+
missed |
|
sync committee
period boundary
```
This patch addresses this edge case by including the slot at which the
`sync_aggregate` was created into the `LightClientUpdate` object.
Note that the `signature_slot` cannot be trusted beyond the purpose of
signature verification, as it could be manipulated to any other slot
within the same sync committee period and fork version, without making
the `sync_aggregate` invalid.
Documentation on how to call `prepare_execution_payload` had the params
for `safe_block_hash` and `finalized_block` hash flipped compared to the
function definition. Also updated tests for consistency.
There were a couple instances where a division was used on an epoch
to derive the corresponding sync committee period instead of calling the
`compute_sync_committee_period` function.
These instances were changed to also use the function.
This renames the `sync_committee_aggregate` field of `LightClientUpdate`
to `sync_aggregate` for consistency with the terminology in the rest of
the spec.
Runtime configurations apply to a certain network and the name of that
network is useful for humans such that they can talk about it.
Some of the existing configs already include a `CONFIG_NAME` toggle -
might as well add it here as well and avoid some confusion - this name
above all becomes useful in the beacon API.
By extension, the `CONFIG_NAME` config will appear in the beacon api as
a result of being defined here.
There are two similar functions to compute the timestamp for a given
beacon chain slot. `compute_time_at_slot` is used for processing Eth1
votes, and does not take into account `GENESIS_TIME`. The other one,
`compute_timestamp_at_slot`, is used everywhere else. When processing
`ExecutionPayload`, the `merge/beacon-chain.md` spec uses the latter,
`compute_timestamp_at_slot`, to verify the timestamp. However, in the
test code, `build_empty_execution_payload` uses `compute_time_at_slot`.
This patch changes the test to use the same function for creating the
timestamp that is later used to verify it. Note that `GENESIS_TIME` is 0
so there is no practical difference.
Some tests are currently restricted to a single phase using @with_phases
even though they could likely run unchanged in later phases. This patch
changes the default for such tests to also run in later phases. If the
beacon chain changes enough in later phases to break these tests, this
highlights that the tests need to be adjusted or extended accordingly.
Building merkle proofs is required functionality for implementing light
client sync. Although the spec currently only defines a function to
verify merkle proofs (`is_valid_merkle_branch`) there are still a few
PySpec unit tests that produce merkle proofs. This patch adds a new
generator to extract test vectors from those static unit tests, so that
light client implementations can validate their merkle proof logic.
Hsiao-Wei Wang
Etan Kissling
Potuz
George Kadianakis
Alex Stokes
inphi
terence tsao
Jim McDonald
protolambda
Danny Ryan
Justin Traglia
Dmitrii Shmatko
Mikhail Kalinin
Aditya Asgaonkar
Jacek Sieka
Caspar Schwarz-Schilling