Different roots in header use different algorithms, and not Eth2.0-compatible

[yangby-cryptape]

Contact Details

No response

Current Behavior

Different roots in block header use different algorithms and different default values.

• The default value for TrieMerkle.root_hash, when there are no data, is hash(rlp(null)).

            root: Node::Empty,
            root_hash: hasher.digest(rlp::NULL_RLP.as_ref()),

  Ref: citahub/cita-trie

• Transactions root for empty list is hash(rlp(null)).

  axon/core/consensus/src/engine.rs

  Lines 71 to 79 in 4ef2f56

  	let txs_root = if !txs.hashes.is_empty() {
  	TrieMerkle::from_iter(txs.hashes.iter().enumerate())
  	.root_hash()
  	.unwrap_or_else(|err| {
  	panic!("failed to calculate trie root hash for transactions since {err}")
  	})
  	} else {
  	RLP_NULL
  	};

  I checked that RLP_NULL == hash(rlp(null)), and a unit test will be added later.

• Receipts root for empty list is hash(rlp(null)).

  axon/core/executor/src/lib.rs

  Lines 191 to 195 in 4ef2f56

  	let receipt_root = TrieMerkle::from_iter(hashes.iter().enumerate())
  	.root_hash()
  	.unwrap_or_else(|err| {
  	panic!("failed to calculate trie root hash for receipts since {err}")
  	});

• Signed transactions hash for empty list is hash(rlp([])).

  axon/core/consensus/src/engine.rs

  Line 86 in 4ef2f56

  signed_txs_hash: digest_signed_transactions(&signed_txs),

  axon/core/consensus/src/util.rs

  Lines 17 to 19 in 4ef2f56

  	pub fn digest_signed_transactions(stxs: &[SignedTransaction]) -> Hash {
  	Hasher::digest(rlp::encode_list(stxs))
  	}

• Default value for metadata_root and cell_header_root is 0x0000..0000.

  axon/core/executor/src/adapter/mod.rs

  Lines 287 to 293 in 4ef2f56

  	pub fn get_metadata_root(&self) -> H256 {
  	self.storage(METADATA_CONTRACT_ADDRESS, *METADATA_ROOT_KEY)
  	}
  	pub fn get_image_cell_root(&self) -> H256 {
  	self.storage(IMAGE_CELL_CONTRACT_ADDRESS, *HEADER_CELL_ROOT_KEY)
  	}

  axon/core/executor/src/adapter/mod.rs

  Lines 189 to 213 in 4ef2f56

  	fn storage(&self, address: H160, index: H256) -> H256 {
  	if let Ok(raw) = self.trie.get(address.as_bytes()) {
  	if raw.is_none() {
  	return H256::default();
  	}
  	Account::decode(raw.unwrap())
  	.and_then(|account| {
  	let storage_root = account.storage_root;
  	if storage_root == RLP_NULL {
  	Ok(H256::default())
  	} else {
  	MPTTrie::from_root(storage_root, Arc::clone(&self.db)).map(
  	|trie| match trie.get(index.as_bytes()) {
  	Ok(Some(res)) => H256::from_slice(res.as_ref()),
  	_ => H256::default(),
  	},
  	)
  	}
  	})
  	.unwrap_or_default()
  	} else {
  	H256::default()
  	}
  	}

Ethereum has defined the following roots, as of today (2023-08-15):

• transactions_root

  • Eth1.0: Default value is hash(rlp(null)).

  • Eth2.0: Default value is ssz_root(null).

  Ref: EIP-6404.

• receipts_root

  Default value is hash(rlp(null)).

Expected Behavior

Default values:

• transactions_root: hash(rlp(null))
• receipts_root: hash(rlp(null)).
• signed_txs_hash: hash(rlp([]))
  Different with above roots, the inner is an empty list.
• metadata_root: H256::default().
  metadata_root should be treated as an optional value:
  • H256::default() means it's null.
  • hash(rlp(null)) is the default value when it's not null.
• cell_header_root: H256::default().
  Same as metadata_root.

OS

Not Associated

Axon version

No response

Kernel

Not Associated

Relevant log output

No response

Anything else?

Since Axon uses MPT root for all roots, but Ethereum uses SSZ root for all roots.

Maybe Axon has to update the README.md as following:

- Axon is compatible with Ethereum so that all of the develop utilities can be used on it directly.
+ Axon is compatible with Ethereum 1.0 so that all of the develop utilities can be used on it directly.