Introduce high-level logic of new efficient block validation

specs/eip4844/beacon-chain.md

@@ -45,6 +45,7 @@ This upgrade adds blobs to the beacon chain as part of EIP-4844.
 | `Blob` | `Vector[BLSFieldElement, FIELD_ELEMENTS_PER_BLOB]` | |
 | `VersionedHash` | `Bytes32` | |
 | `KZGCommitment` | `Bytes48` | Same as BLS standard "is valid pubkey" check but also allows `0x00..00` for point-at-infinity |
+| `KZGProof` | Bytes48 | Same as for `KZGCommitment` |
 
 ## Constants
 

specs/eip4844/p2p-interface.md

@@ -57,6 +57,7 @@ class BlobsSidecar(Container):
     beacon_block_root: Root
     beacon_block_slot: Slot
     blobs: List[Blob, MAX_BLOBS_PER_BLOCK]
+    kzg_aggregated_proof: KZGProof
 ```
 
 ### `SignedBlobsSidecar`
@@ -114,6 +115,7 @@ The following validations MUST pass before forwarding the `signed_blobs_sidecar`
 Alias `sidecar = signed_blobs_sidecar.message`.
 - _[IGNORE]_ the `sidecar.beacon_block_slot` is for the current slot (with a `MAXIMUM_GOSSIP_CLOCK_DISPARITY` allowance) -- i.e. `blobs_sidecar.beacon_block_slot == current_slot`.
 - _[REJECT]_ the `sidecar.blobs` are all well formatted, i.e. the `BLSFieldElement` in valid range (`x < BLS_MODULUS`).
+- _[REJECT]_ The KZG proof is a correctly encoded compressed BLS G1 Point -- i.e. `bls.KeyValidate(blobs_sidecar.kzg_aggregated_proof)
 - _[REJECT]_ the beacon proposer signature, `signed_blobs_sidecar.signature`, is valid -- i.e.
 ```python
 domain = get_domain(state, DOMAIN_BLOBS_SIDECAR, blobs_sidecar.beacon_block_slot // SLOTS_PER_EPOCH)

specs/eip4844/validator.md

@@ -59,9 +59,25 @@ def verify_blobs_sidecar(slot: Slot, beacon_block_root: Root,
     assert slot == blobs_sidecar.beacon_block_slot
     assert beacon_block_root == blobs_sidecar.beacon_block_root
     blobs = blobs_sidecar.blobs
+    kzg_aggregated_proof = blobs_sidecar.kzg_aggregated_proof
     assert len(expected_kzgs) == len(blobs)
-    for kzg, blob in zip(expected_kzgs, blobs):
-        assert blob_to_kzg(blob) == kzg
+
+    # Generate random linear combination challenges
+    r = hash_to_bls_field([blobs, expected_kzgs])
+    r_powers = compute_powers(r, len(expected_kzgs))
+
+    # Compute commitment to aggregated polynomial
+    aggregated_poly_commitment = lincomb(expected_kzgs, r_powers)
+
+    # Create aggregated polynomial in evaluation form
+    aggregated_poly = vector_lincomb(blobs, r_powers)
+
+    # Generate challenge `x` and evaluate the aggregated polynomial at `x`
+    x = hash_to_bls_field([aggregated_poly, aggregated_poly_commitment])
+    y = evaluate_polynomial_in_evaluation_form(aggregated_poly, x)
+
+    # Verify aggregated proof
+    assert verify_kzg_proof(aggregated_poly_commitment, x, y, kzg_aggregated_proof)
 ```