Add HistoricalSummariesBlockProof for headers from Capella onwards

history-network.md

@@ -160,16 +160,18 @@ each receipt/transaction and re-rlp-encode it, but only if it is a legacy transa
 
 #### Block Header
 
-
 ```python
-# Content types
-
+# Pre-merge BlockHeader proof
 AccumulatorProof = Vector[Bytes32, 15]
 
+# Post-merge Beacon proofs
 BeaconBlockBodyProof = Vector[Bytes32, 8] # Proof that EL block_hash in ExecutionPayload is part of BeaconBlockBody
 BeaconBlockHeaderProof = Vector[Bytes32, 3] # Proof that BeaconBlockBody root is part of BeaconBlockHeader
+
+# BeaconState historical_roots proof (for post-merge till Capella)
 HistoricalRootsProof = Vector[Bytes32, 14] # Proof that BeaconBlockHeader root is part of HistoricalRoots
 
+# Post-merge until Capella BlockHeader proof
 HistoricalRootsBlockProof = Container[
     beaconBlockBodyProof: BeaconBlockBodyProof,
     beaconBlockBodyRoot: Bytes32,
@@ -179,8 +181,21 @@ HistoricalRootsBlockProof = Container[
     slot: Slot
 ]
 
-BlockHeaderProof = Union[None, AccumulatorProof, HistoricalRootsBlockProof]
+# BeaconState historical_summaries proof (for Capella onwards)
+HistoricalSummariesProof = Vector[Bytes32, 13] # Proof that BeaconBlockHeader root is part of HistoricalSummaries
+
+HistoricalSummariesBlockProof = Container[
+    beaconBlockBodyProof: BeaconBlockBodyProof,
+    beaconBlockBodyRoot: Bytes32,
+    beaconBlockHeaderProof: BeaconBlockHeaderProof,
+    beaconBlockHeaderRoot: Bytes32,
+    historicalSummariesProof: HistoricalSummariesProof,
+    slot: Slot
+]
+
+BlockHeaderProof = Union[None, AccumulatorProof, HistoricalRootsBlockProof, HistoricalSummariesBlockProof]
 
+# Content type
 BlockHeaderWithProof = Container[
   header: ByteList, # RLP encoded header in SSZ ByteList
   proof: BlockHeaderProof
@@ -203,8 +218,8 @@ content_key      = selector + SSZ.serialize(block_header_key)
 For pre-merge headers, clients SHOULD NOT accept headers without a proof
 as there is the `AccumulatorProof` solution available.
 For post-merge until Capella headers, clients SHOULD NOT accept headers without a proof as there is the `HistoricalRootsBlockProof` solution available.
-
-For post Capella headers, there is currently no proof solution and clients SHOULD
+For Capella headers, clients SHOULD NOT accept headers without a proof as there is the `HistoricalSummariesBlockProof` solution available.
+For headers that are not yet part of the last period, clients SHOULD
 accept headers without a proof.
 
 #### Block Body
@@ -359,3 +374,12 @@ The container holds a chain of proofs. This chain of proofs allows for verifying
 The `historical_roots` is a [`BeaconState` field](https://github.com/ethereum/consensus-specs/blob/dev/specs/capella/beacon-chain.md#beaconstate) that is frozen since the Capella fork. The `HistoricalRootsBlockProof` MUST be used to verify blocks from The Merge until the Capella fork.
 
 The Portal network does not provide a mechanism to acquire the `historical_roots` over the network. Clients are encouraged to solve this however they choose, with the suggestion that they can include a frozen copy of the `historical_roots` within their client code, and provide a mechanism for users to override this value if they so choose.
+
+#### HistoricalSummariesBlockProof
+
+The `HistoricalSummariesBlockProof` is an SSZ container which holds three Merkle proofs as specified in the [SSZ Merke proofs specification](https://github.com/ethereum/consensus-specs/blob/dev/ssz/merkle-proofs.md#merkle-multiproofs).
+
+The container holds a chain of proofs. This chain of proofs allows for verifying that an EL `BlockHeader` is part of the canonical chain. The only requirement is having access to the beacon chain `historical_summaries`.
+The `historical_summaries` is a [`BeaconState` field](https://github.com/ethereum/consensus-specs/blob/dev/specs/capella/beacon-chain.md#beaconstate) that was introduced since the Capella fork. It gets updated every period (8192 slots). The `HistoricalRHistoricalSummariesBlockProofootsBlockProof` MUST be used to verify blocks from the Capella fork onwards.
+
+The Portal beacon network [provides access](./beacon-chain/beacon-network.md#historicalsummaries) to an up to date `historical_summaries` object.