nimbus-eth2/beacon_chain/el/merkle_minimal.nim

44 lines
1.7 KiB
Nim

# beacon_chain
# Copyright (c) 2018-2024 Status Research & Development GmbH
# Licensed and distributed under either of
# * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT).
# * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0).
# at your option. This file may not be copied, modified, or distributed except according to those terms.
{.push raises: [].}
# https://github.com/ethereum/consensus-specs/blob/v1.5.0-alpha.5/tests/core/pyspec/eth2spec/utils/merkle_minimal.py
# Merkle tree helpers
# ---------------------------------------------------------------
import
std/sequtils,
stew/endians2,
# Specs
../spec/[eth2_merkleization, digest],
../spec/datatypes/base
template getProof*(
proofs: seq[Eth2Digest], idxParam: int): openArray[Eth2Digest] =
let
idx = idxParam
## TODO: It's surprising that we have to do +1 here.
## It seems that `depositContractLimit` is set too high.
startIdx = idx * (DEPOSIT_CONTRACT_TREE_DEPTH + 1)
endIdx = startIdx + DEPOSIT_CONTRACT_TREE_DEPTH - 1
proofs.toOpenArray(startIdx, endIdx)
func attachMerkleProofs*(deposits: var openArray[Deposit]): Eth2Digest =
let depositsRoots = mapIt(deposits, hash_tree_root(it.data))
var merkleizer = createMerkleizer2(DEPOSIT_CONTRACT_TREE_DEPTH + 1)
let proofs = merkleizer.addChunksAndGenMerkleProofs(depositsRoots)
for i in 0 ..< depositsRoots.len:
deposits[i].proof[0 ..< DEPOSIT_CONTRACT_TREE_DEPTH] = getProof(proofs, i)
deposits[i].proof[DEPOSIT_CONTRACT_TREE_DEPTH] = default(Eth2Digest)
deposits[i].proof[DEPOSIT_CONTRACT_TREE_DEPTH].data[0..7] =
toBytesLE deposits.lenu64
mixInLength(merkleizer.getFinalHash(), deposits.len)