Merge pull request #7 from semiotic-ai/suchapalaver/test-inclusion-pr…

…oof-for-block-body-given_eth1-data

Test inclusion proof for block body given eth1 data

README.md

@@ -9,6 +9,7 @@ Blackboxing validating post-merge Ethereum data in practice to figure out the ne
 - Notion doc on
 [Post-merge Header Record Data Structure](https://www.notion.so/semiotic/Post-merge-header_record-data-structure-7290d03d356946188bdb9ac29366f510?pvs=4).
 - [Beacon Chain `BeaconState` spec](https://github.com/ethereum/consensus-specs/blob/dev/specs/capella/beacon-chain.md#beaconstate)
+- [Beacon Chain `BeaconBlockBody` spec](https://github.com/ethereum/consensus-specs/blob/dev/specs/deneb/beacon-chain.md#beaconblockbody)
 - The [fork of `sigp/lighthouse`](https://github.com/semiotic-ai/lighthouse) we've been spiking.
 - [Google Drive shared resources](https://drive.google.com/drive/u/1/folders/15diM-Gu4WFg9FrMWti3_B8xP0J0szUhW),
 including `head-state.json` used in `head_state.rs` tests.
@@ -17,4 +18,5 @@ including `head-state.json` used in `head_state.rs` tests.
 
 > [!NOTE]
 > You need to add the `head-state.json` file from our shared Google Drive to
-> the root of this repo to run tests!
+> the root of this repo to run tests, as well as the
+> [`bb-8786333.json`](https://drive.google.com/file/d/1-9SgmdxrOU5t1XlBc0hsRcEM-xZVN91N/view?usp=drive_link)!

src/beacon_block.rs

@@ -0,0 +1,72 @@
+use serde::{Deserialize, Serialize};
+use types::{BeaconBlock, MainnetEthSpec};
+
+#[derive(Debug, Deserialize, Serialize)]
+pub struct BlockWrapper {
+    pub version: String,
+    pub execution_optimistic: bool,
+    pub finalized: bool,
+    pub data: Data,
+}
+
+#[derive(Debug, Deserialize, Serialize)]
+pub struct Data {
+    pub message: BeaconBlock<MainnetEthSpec>,
+}
+
+/// Merkle proof depth for a `BeaconBlockBody` struct with 12 fields.
+///
+/// The proof depth is determined by finding the smallest power of 2 that is
+/// greater than or equal to the number of fields. In this case, the number of
+/// fields is 12, which is between 8 (2^3) and 16 (2^4).
+pub const BEACON_BLOCK_BODY_PROOF_DEPTH: usize = 4;
+
+/// The field corresponds to the index of the `eth1_data` field in the [`BeaconBlockBody`] struct:
+/// <https://github.com/ethereum/annotated-spec/blob/master/deneb/beacon-chain.md#beaconblockbody>.
+pub const ETH1_DATA_FIELD_INDEX: usize = 1;
+
+#[cfg(test)]
+mod tests {
+    use std::cell::LazyCell;
+
+    use super::*;
+
+    use merkle_proof::verify_merkle_proof;
+    use tree_hash::TreeHash;
+    use types::{light_client_update::ETH1_DATA_INDEX, BeaconBlockBody};
+
+    const DENEB_BLOCK_JSON: &str = include_str!("../bb-8786333.json");
+
+    const BLOCK_WRAPPER: LazyCell<BlockWrapper> = LazyCell::new(|| {
+        serde_json::from_str(DENEB_BLOCK_JSON).expect(
+            "For this spike we are using a Deneb block JSON file that has been shared among contributors",
+        )
+    });
+
+    #[test]
+    fn test_inclusion_proof_for_block_body_given_eth1_data() {
+        let block_wrapper = &BLOCK_WRAPPER;
+        let block = &block_wrapper.data.message;
+
+        let eth1_data = block.body().eth1_data();
+        let eth1_data_root = eth1_data.tree_hash_root();
+
+        let block_body = block.body_deneb().unwrap();
+        let block_body_hash = block_body.tree_hash_root();
+
+        let body = BeaconBlockBody::from(block_body.clone());
+        let proof = body.block_body_merkle_proof(ETH1_DATA_INDEX).unwrap();
+
+        let depth = BEACON_BLOCK_BODY_PROOF_DEPTH;
+
+        assert_eq!(proof.len(), depth, "proof length should equal depth");
+
+        assert!(verify_merkle_proof(
+            eth1_data_root,
+            &proof,
+            depth,
+            ETH1_DATA_FIELD_INDEX,
+            block_body_hash
+        ));
+    }
+}

src/head_state.rs → src/beacon_state.rs

@@ -3,6 +3,9 @@ use serde::{Deserialize, Serialize};
 use tree_hash::TreeHash;
 use types::{BeaconState, Error, EthSpec, MainnetEthSpec};
 
+pub const HISTORICAL_ROOTS_FIELD_INDEX: usize = 7;
+pub const HISTORICAL_SUMMARIES_FIELD_INDEX: usize = 27;
+
 #[derive(Clone, Debug, Deserialize, Serialize)]
 pub struct HeadState<E: EthSpec> {
     version: String,
@@ -53,9 +56,6 @@ mod tests {
 
     const HEAD_STATE_JSON: &str = include_str!("../head-state.json");
 
-    const HISTORICAL_ROOTS_FIELD_INDEX: usize = 7;
-    const HISTORICAL_SUMMARIES_FIELD_INDEX: usize = 27;
-
     const STATE: LazyCell<HeadState<MainnetEthSpec>> = LazyCell::new(|| {
         serde_json::from_str(HEAD_STATE_JSON).expect(
             "For this spike we are using a 'head-state.json' file that has been shared among contributors",

src/lib.rs

@@ -1 +1,2 @@
-pub mod head_state;
+pub mod beacon_block;
+pub mod beacon_state;