EIP-4881: Spec implementation (#11720)

* Initial spec rewrite * Finish adding merkle tree implementation * Last bits * Move reverse function * Add comments * Add deposit tree snapshot * Add deposit tree * Add comments + cleanup * Fixes * Add missing errors * Small fixes * Add unhandled error * Cleanup * Fix unsafe file.Close * Add missing comments * Small fixes * Address some of deepSource' compaints * Add depositCount check * Add finalizedDeposit check * Replace pointer magic with copy() * Add test for slice reversal * add back bytes method * Add package level description * Remove zerohash gen and add additional checks * Add additional comments * Small lint fixes * Forgot an error * Small fixes * Move Uint64ToBytesLittleEndian32 + test * Fix uint subtraction issue * Move mixInLength below error handling * Fix * Fix deposit root --------- Co-authored-by: rauljordan <raul@prysmaticlabs.com> Co-authored-by: prylabs-bulldozer[bot] <58059840+prylabs-bulldozer[bot]@users.noreply.github.com>
2026-01-08 07:03:58 -05:00 · 2023-01-27 18:35:25 +01:00
parent eca129d8ff
commit 9529c73ff1
9 changed files with 672 additions and 5 deletions
--- a/beacon-chain/cache/depositsnapshot/BUILD.bazel
+++ b/beacon-chain/cache/depositsnapshot/BUILD.bazel
@@ -2,7 +2,20 @@ load("@prysm//tools/go:def.bzl", "go_library")

 go_library(
    name = "go_default_library",
-    srcs = ["merkle_tree.go"],
+    srcs = [
+        "deposit_tree.go",
+        "deposit_tree_snapshot.go",
+        "merkle_tree.go",
+        "zerohashes.gen.go",
+    ],
    importpath = "github.com/prysmaticlabs/prysm/v3/beacon-chain/cache/depositsnapshot",
    visibility = ["//visibility:public"],
+    deps = [
+        "//container/slice:go_default_library",
+        "//crypto/hash:go_default_library",
+        "//encoding/bytesutil:go_default_library",
+        "//math:go_default_library",
+        "//proto/eth/v1:go_default_library",
+        "@com_github_pkg_errors//:go_default_library",
+    ],
 )
--- a/beacon-chain/cache/depositsnapshot/deposit_tree.go
+++ b/beacon-chain/cache/depositsnapshot/deposit_tree.go
@@ -0,0 +1,157 @@
+// Package depositsnapshot implements the EIP-4881 standard for minimal sparse Merkle tree.
+// The format proposed by the EIP allows for the pruning of deposits that are no longer needed to participate fully in consensus.
+// Full EIP-4881 specification can be found here: https://eips.ethereum.org/EIPS/eip-4881
+package depositsnapshot
+
+import (
+	"crypto/sha256"
+
+	"github.com/pkg/errors"
+	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
+	"github.com/prysmaticlabs/prysm/v3/math"
+	eth "github.com/prysmaticlabs/prysm/v3/proto/eth/v1"
+)
+
+var (
+	// ErrEmptyExecutionBlock occurs when the execution block is nil.
+	ErrEmptyExecutionBlock = errors.New("empty execution block")
+	// ErrInvalidSnapshotRoot occurs when the snapshot root does not match the calculated root.
+	ErrInvalidSnapshotRoot = errors.New("snapshot root is invalid")
+	// ErrInvalidMixInLength occurs when the value for mix in length is 0.
+	ErrInvalidMixInLength = errors.New("mixInLength should be greater than 0")
+	// ErrInvalidIndex occurs when the index is less than the number of finalized deposits.
+	ErrInvalidIndex = errors.New("index should be greater than finalizedDeposits - 1")
+	// ErrNoDeposits occurs when the number of deposits is 0.
+	ErrNoDeposits = errors.New("number of deposits should be greater than 0")
+	// ErrNoFinalizedDeposits occurs when the number of finalized deposits is 0.
+	ErrNoFinalizedDeposits = errors.New("number of finalized deposits should be greater than 0")
+	// ErrTooManyDeposits occurs when the number of deposits exceeds the capacity of the tree.
+	ErrTooManyDeposits = errors.New("number of deposits should not be greater than the capacity of the tree")
+)
+
+// DepositTree is the Merkle tree representation of deposits.
+type DepositTree struct {
+	tree                    MerkleTreeNode
+	mixInLength             uint64 // number of deposits in the tree, reference implementation calls this mix_in_length.
+	finalizedExecutionBlock executionBlock
+}
+
+type executionBlock struct {
+	Hash  [32]byte
+	Depth uint64
+}
+
+// New creates an empty deposit tree.
+//
+//nolint:unused
+func New() *DepositTree {
+	var leaves [][32]byte
+	merkle := create(leaves, DepositContractDepth)
+	return &DepositTree{
+		tree:                    merkle,
+		mixInLength:             0,
+		finalizedExecutionBlock: executionBlock{},
+	}
+}
+
+// getSnapshot returns a deposit tree snapshot.
+//
+//nolint:unused
+func (d *DepositTree) getSnapshot() (DepositTreeSnapshot, error) {
+	if d.finalizedExecutionBlock == (executionBlock{}) {
+		return DepositTreeSnapshot{}, ErrEmptyExecutionBlock
+	}
+	var finalized [][32]byte
+	depositCount, _ := d.tree.GetFinalized(finalized)
+	return fromTreeParts(finalized, depositCount, d.finalizedExecutionBlock)
+}
+
+// fromSnapshot returns a deposit tree from a deposit tree snapshot.
+//
+//nolint:unused
+func fromSnapshot(snapshot DepositTreeSnapshot) (DepositTree, error) {
+	root, err := snapshot.CalculateRoot()
+	if err != nil {
+		return DepositTree{}, err
+	}
+	if snapshot.depositRoot != root {
+		return DepositTree{}, ErrInvalidSnapshotRoot
+	}
+	if snapshot.depositCount >= math.PowerOf2(uint64(DepositContractDepth)) {
+		return DepositTree{}, ErrTooManyDeposits
+	}
+	tree, err := fromSnapshotParts(snapshot.finalized, snapshot.depositCount, DepositContractDepth)
+	if err != nil {
+		return DepositTree{}, err
+	}
+	if snapshot.depositCount == 0 {
+		return DepositTree{}, ErrNoDeposits
+	}
+	return DepositTree{
+		tree:                    tree,
+		mixInLength:             snapshot.depositCount,
+		finalizedExecutionBlock: snapshot.executionBlock,
+	}, nil
+}
+
+// finalize marks a deposit as finalized.
+//
+//nolint:unused
+func (d *DepositTree) finalize(eth1data *eth.Eth1Data, executionBlockHeight uint64) error {
+	var blockHash [32]byte
+	copy(blockHash[:], eth1data.BlockHash)
+	d.finalizedExecutionBlock = executionBlock{
+		Hash:  blockHash,
+		Depth: executionBlockHeight,
+	}
+	_, err := d.tree.Finalize(eth1data.DepositCount, DepositContractDepth)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+// getProof returns the Deposit tree proof.
+//
+//nolint:unused
+func (d *DepositTree) getProof(index uint64) ([32]byte, [][32]byte, error) {
+	if d.mixInLength <= 0 {
+		return [32]byte{}, nil, ErrInvalidMixInLength
+	}
+	finalizedDeposits, _ := d.tree.GetFinalized([][32]byte{})
+	if finalizedDeposits == 0 {
+		return [32]byte{}, nil, ErrNoFinalizedDeposits
+	}
+	if finalizedDeposits != 0 {
+		finalizedDeposits = finalizedDeposits - 1
+	}
+	if index <= finalizedDeposits {
+		return [32]byte{}, nil, ErrInvalidIndex
+	}
+	leaf, proof := generateProof(d.tree, index, DepositContractDepth)
+	var mixInLength [32]byte
+	copy(mixInLength[:], bytesutil.Uint64ToBytesLittleEndian32(d.mixInLength))
+	proof = append(proof, mixInLength)
+	return leaf, proof, nil
+}
+
+// getRoot returns the root of the deposit tree.
+//
+//nolint:unused
+func (d *DepositTree) getRoot() [32]byte {
+	root := d.tree.GetRoot()
+	return sha256.Sum256(append(root[:], bytesutil.Uint64ToBytesLittleEndian32(d.mixInLength)...))
+}
+
+// pushLeaf adds a new leaf to the tree.
+//
+//nolint:unused
+func (d *DepositTree) pushLeaf(leaf [32]byte) error {
+	var err error
+	d.tree, err = d.tree.PushLeaf(leaf, DepositContractDepth)
+	if err != nil {
+		return err
+	}
+	d.mixInLength++
+	return nil
+}
--- a/beacon-chain/cache/depositsnapshot/deposit_tree_snapshot.go
+++ b/beacon-chain/cache/depositsnapshot/deposit_tree_snapshot.go
@@ -0,0 +1,62 @@
+package depositsnapshot
+
+import (
+	"crypto/sha256"
+
+	"github.com/pkg/errors"
+	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
+)
+
+var (
+	// ErrZeroIndex occurs when the value of index is 0.
+	ErrZeroIndex = errors.New("index should be greater than 0")
+)
+
+// DepositTreeSnapshot represents the data used to create a
+// deposit tree given a snapshot.
+//
+//nolint:unused
+type DepositTreeSnapshot struct {
+	finalized      [][32]byte
+	depositRoot    [32]byte
+	depositCount   uint64
+	executionBlock executionBlock
+}
+
+// CalculateRoot returns the root of a deposit tree snapshot.
+func (ds *DepositTreeSnapshot) CalculateRoot() ([32]byte, error) {
+	size := ds.depositCount
+	index := len(ds.finalized)
+	root := Zerohashes[0]
+	for i := 0; i < DepositContractDepth; i++ {
+		if (size & 1) == 1 {
+			if index == 0 {
+				return [32]byte{}, ErrZeroIndex
+			}
+			index--
+			root = sha256.Sum256(append(ds.finalized[index][:], root[:]...))
+		} else {
+			root = sha256.Sum256(append(root[:], Zerohashes[i][:]...))
+		}
+		size >>= 1
+	}
+	return sha256.Sum256(append(root[:], bytesutil.Uint64ToBytesLittleEndian(ds.depositCount)...)), nil
+}
+
+// fromTreeParts constructs the deposit tree from pre-existing data.
+//
+//nolint:unused
+func fromTreeParts(finalised [][32]byte, depositCount uint64, executionBlock executionBlock) (DepositTreeSnapshot, error) {
+	snapshot := DepositTreeSnapshot{
+		finalized:      finalised,
+		depositRoot:    Zerohashes[0],
+		depositCount:   depositCount,
+		executionBlock: executionBlock,
+	}
+	root, err := snapshot.CalculateRoot()
+	if err != nil {
+		return snapshot, ErrInvalidSnapshotRoot
+	}
+	snapshot.depositRoot = root
+	return snapshot, nil
+}
--- a/beacon-chain/cache/depositsnapshot/merkle_tree.go
+++ b/beacon-chain/cache/depositsnapshot/merkle_tree.go
@@ -1,5 +1,28 @@
 package depositsnapshot

+import (
+	"github.com/pkg/errors"
+	"github.com/prysmaticlabs/prysm/v3/container/slice"
+	"github.com/prysmaticlabs/prysm/v3/crypto/hash"
+	"github.com/prysmaticlabs/prysm/v3/math"
+)
+
+const (
+	// DepositContractDepth is the maximum tree depth as defined by EIP-4881.
+	DepositContractDepth = 32
+)
+
+var (
+	// ErrFinalizedNodeCannotPushLeaf may occur when attempting to push a leaf to a finalized node. When a node is finalized, it cannot be modified or changed.
+	ErrFinalizedNodeCannotPushLeaf = errors.New("can't push a leaf to a finalized node")
+	// ErrLeafNodeCannotPushLeaf may occur when attempting to push a leaf to a leaf node.
+	ErrLeafNodeCannotPushLeaf = errors.New("can't push a leaf to a leaf node")
+	// ErrZeroLevel occurs when the value of level is 0.
+	ErrZeroLevel = errors.New("level should be greater than 0")
+	// ErrZeroDepth occurs when the value of depth is 0.
+	ErrZeroDepth = errors.New("depth should be greater than 0")
+)
+
 // MerkleTreeNode is the interface for a Merkle tree.
 type MerkleTreeNode interface {
 	// GetRoot returns the root of the Merkle tree.
@@ -7,9 +30,295 @@ type MerkleTreeNode interface {
 	// IsFull returns whether there is space left for deposits.
 	IsFull() bool
 	// Finalize marks deposits of the Merkle tree as finalized.
-	Finalize(deposits uint, depth uint) MerkleTreeNode
-	// GetFinalized returns a list of hashes of all the finalized nodes and the number of deposits.
-	GetFinalized(result [][32]byte) ([][32]byte, uint)
+	Finalize(depositsToFinalize uint64, depth uint64) (MerkleTreeNode, error)
+	// GetFinalized returns the number of deposits and a list of hashes of all the finalized nodes.
+	GetFinalized(result [][32]byte) (uint64, [][32]byte)
 	// PushLeaf adds a new leaf node at the next available Zero node.
-	PushLeaf(leaf [32]byte, deposits uint, depth uint) MerkleTreeNode
+	PushLeaf(leaf [32]byte, depth uint64) (MerkleTreeNode, error)
+
+	// Right represents the right child of a node.
+	Right() MerkleTreeNode
+	// Left represents the left child of a node.
+	Left() MerkleTreeNode
+}
+
+// create builds a new merkle tree
+func create(leaves [][32]byte, depth uint64) MerkleTreeNode {
+	length := uint64(len(leaves))
+	if length == 0 {
+		return &ZeroNode{depth: depth}
+	}
+	if depth == 0 {
+		return &LeafNode{hash: leaves[0]}
+	}
+	split := math.Min(math.PowerOf2(depth-1), length)
+	left := create(leaves[0:split], depth-1)
+	right := create(leaves[split:], depth-1)
+	return &InnerNode{left: left, right: right}
+}
+
+// fromSnapshotParts creates a new Merkle tree from a list of finalized leaves, number of deposits and specified depth.
+//
+//nolint:unused
+func fromSnapshotParts(finalized [][32]byte, deposits uint64, level uint64) (_ MerkleTreeNode, err error) {
+	if len(finalized) < 1 || deposits == 0 {
+		return &ZeroNode{
+			depth: level,
+		}, nil
+	}
+	if deposits == math.PowerOf2(level) {
+		return &FinalizedNode{
+			depositCount: deposits,
+			hash:         finalized[0],
+		}, nil
+	}
+	if level == 0 {
+		return &ZeroNode{}, ErrZeroLevel
+	}
+	node := InnerNode{}
+	if leftSubtree := math.PowerOf2(level - 1); deposits <= leftSubtree {
+		node.left, err = fromSnapshotParts(finalized, deposits, level-1)
+		if err != nil {
+			return &ZeroNode{}, err
+		}
+		node.right = &ZeroNode{depth: level - 1}
+	} else {
+		node.left = &FinalizedNode{
+			depositCount: leftSubtree,
+			hash:         finalized[0],
+		}
+		node.right, err = fromSnapshotParts(finalized[1:], deposits-leftSubtree, level-1)
+		if err != nil {
+			return &ZeroNode{}, err
+		}
+	}
+	return &node, nil
+}
+
+// generateProof returns a merkle proof and root
+//
+//nolint:unused
+func generateProof(tree MerkleTreeNode, index uint64, depth uint64) ([32]byte, [][32]byte) {
+	var proof [][32]byte
+	node := tree
+	for depth > 0 {
+		ithBit := (index >> (depth - 1)) & 0x1
+		if ithBit == 1 {
+			proof = append(proof, node.Left().GetRoot())
+			node = node.Right()
+		} else {
+			proof = append(proof, node.Right().GetRoot())
+			node = node.Left()
+		}
+		depth--
+	}
+	proof = slice.Reverse(proof)
+	return node.GetRoot(), proof
+}
+
+// FinalizedNode represents a finalized node and satisfies the MerkleTreeNode interface.
+type FinalizedNode struct {
+	depositCount uint64
+	hash         [32]byte
+}
+
+// GetRoot returns the root of the Merkle tree.
+func (f *FinalizedNode) GetRoot() [32]byte {
+	return f.hash
+}
+
+// IsFull returns whether there is space left for deposits.
+// A FinalizedNode will always return true as by definition it
+// is full and deposits can't be added to it.
+func (_ *FinalizedNode) IsFull() bool {
+	return true
+}
+
+// Finalize marks deposits of the Merkle tree as finalized.
+func (f *FinalizedNode) Finalize(depositsToFinalize uint64, depth uint64) (MerkleTreeNode, error) {
+	return f, nil
+}
+
+// GetFinalized returns a list of hashes of all the finalized nodes and the number of deposits.
+func (f *FinalizedNode) GetFinalized(result [][32]byte) (uint64, [][32]byte) {
+	return f.depositCount, append(result, f.hash)
+}
+
+// PushLeaf adds a new leaf node at the next available zero node.
+func (_ *FinalizedNode) PushLeaf(_ [32]byte, _ uint64) (MerkleTreeNode, error) {
+	return nil, ErrFinalizedNodeCannotPushLeaf
+}
+
+// Right returns nil as a finalized node can't have any children.
+func (_ *FinalizedNode) Right() MerkleTreeNode {
+	return nil
+}
+
+// Left returns nil as a finalized node can't have any children.
+func (_ *FinalizedNode) Left() MerkleTreeNode {
+	return nil
+}
+
+// LeafNode represents a leaf node holding a deposit and satisfies the MerkleTreeNode interface.
+type LeafNode struct {
+	hash [32]byte
+}
+
+// GetRoot returns the root of the Merkle tree.
+func (l *LeafNode) GetRoot() [32]byte {
+	return l.hash
+}
+
+// IsFull returns whether there is space left for deposits.
+// A LeafNode will always return true as it is the last node
+// in the tree and therefore can't have any deposits added to it.
+func (_ *LeafNode) IsFull() bool {
+	return true
+}
+
+// Finalize marks deposits of the Merkle tree as finalized.
+func (l *LeafNode) Finalize(depositsToFinalize uint64, depth uint64) (MerkleTreeNode, error) {
+	return &FinalizedNode{1, l.hash}, nil
+}
+
+// GetFinalized returns a list of hashes of all the finalized nodes and the number of deposits.
+func (_ *LeafNode) GetFinalized(result [][32]byte) (uint64, [][32]byte) {
+	return 0, result
+}
+
+// PushLeaf adds a new leaf node at the next available zero node.
+func (_ *LeafNode) PushLeaf(_ [32]byte, _ uint64) (MerkleTreeNode, error) {
+	return nil, ErrLeafNodeCannotPushLeaf
+}
+
+// Right returns nil as a leaf node is the last node and can't have any children.
+func (_ *LeafNode) Right() MerkleTreeNode {
+	return nil
+}
+
+// Left returns nil as a leaf node is the last node and can't have any children.
+func (_ *LeafNode) Left() MerkleTreeNode {
+	return nil
+}
+
+// InnerNode represents an inner node with two children and satisfies the MerkleTreeNode interface.
+type InnerNode struct {
+	left, right MerkleTreeNode
+}
+
+// GetRoot returns the root of the Merkle tree.
+func (n *InnerNode) GetRoot() [32]byte {
+	left := n.left.GetRoot()
+	right := n.right.GetRoot()
+	return hash.Hash(append(left[:], right[:]...))
+}
+
+// IsFull returns whether there is space left for deposits.
+func (n *InnerNode) IsFull() bool {
+	return n.right.IsFull()
+}
+
+// Finalize marks deposits of the Merkle tree as finalized.
+func (n *InnerNode) Finalize(depositsToFinalize uint64, depth uint64) (_ MerkleTreeNode, err error) {
+	deposits := math.PowerOf2(depth)
+	if deposits <= depositsToFinalize {
+		return &FinalizedNode{deposits, n.GetRoot()}, nil
+	}
+	if depth == 0 {
+		return &ZeroNode{}, ErrZeroDepth
+	}
+	n.left, err = n.left.Finalize(depositsToFinalize, depth-1)
+	if err != nil {
+		return &ZeroNode{}, err
+	}
+	if depositsToFinalize > deposits/2 {
+		remaining := depositsToFinalize - deposits/2
+		n.right, err = n.right.Finalize(remaining, depth-1)
+		if err != nil {
+			return &ZeroNode{}, err
+		}
+	}
+	return n, nil
+}
+
+// GetFinalized returns a list of hashes of all the finalized nodes and the number of deposits.
+func (n *InnerNode) GetFinalized(result [][32]byte) (uint64, [][32]byte) {
+	leftDeposits, result := n.left.GetFinalized(result)
+	rightDeposits, result := n.right.GetFinalized(result)
+	return leftDeposits + rightDeposits, result
+}
+
+// PushLeaf adds a new leaf node at the next available zero node.
+func (n *InnerNode) PushLeaf(leaf [32]byte, depth uint64) (MerkleTreeNode, error) {
+	if !n.left.IsFull() {
+		left, err := n.left.PushLeaf(leaf, depth-1)
+		if err == nil {
+			n.left = left
+		} else {
+			return n, err
+		}
+	} else {
+		right, err := n.right.PushLeaf(leaf, depth-1)
+		if err == nil {
+			n.right = right
+		} else {
+			return n, err
+		}
+	}
+	return n, nil
+}
+
+// Right returns the child node on the right.
+func (n *InnerNode) Right() MerkleTreeNode {
+	return n.right
+}
+
+// Left returns the child node on the left.
+func (n *InnerNode) Left() MerkleTreeNode {
+	return n.left
+}
+
+// ZeroNode represents an empty node without a deposit and satisfies the MerkleTreeNode interface.
+type ZeroNode struct {
+	depth uint64
+}
+
+// GetRoot returns the root of the Merkle tree.
+func (z *ZeroNode) GetRoot() [32]byte {
+	if z.depth == DepositContractDepth {
+		return hash.Hash(append(Zerohashes[z.depth-1][:], Zerohashes[z.depth-1][:]...))
+	}
+	return Zerohashes[z.depth]
+}
+
+// IsFull returns wh   ether there is space left for deposits.
+// A ZeroNode will always return false as a ZeroNode is an empty node
+// that gets replaced by a deposit.
+func (_ *ZeroNode) IsFull() bool {
+	return false
+}
+
+// Finalize marks deposits of the Merkle tree as finalized.
+func (_ *ZeroNode) Finalize(depositsToFinalize uint64, depth uint64) (MerkleTreeNode, error) {
+	return nil, nil
+}
+
+// GetFinalized returns a list of hashes of all the finalized nodes and the number of deposits.
+func (_ *ZeroNode) GetFinalized(result [][32]byte) (uint64, [][32]byte) {
+	return 0, result
+}
+
+// PushLeaf adds a new leaf node at the next available zero node.
+func (_ *ZeroNode) PushLeaf(leaf [32]byte, depth uint64) (MerkleTreeNode, error) {
+	return create([][32]byte{leaf}, depth), nil
+}
+
+// Right returns nil as a zero node can't have any children.
+func (_ *ZeroNode) Right() MerkleTreeNode {
+	return nil
+}
+
+// Left returns nil as a zero node can't have any children.
+func (_ *ZeroNode) Left() MerkleTreeNode {
+	return nil
 }
--- a/beacon-chain/cache/depositsnapshot/zerohashes.gen.go
+++ b/beacon-chain/cache/depositsnapshot/zerohashes.gen.go
@@ -0,0 +1,69 @@
+// Code generated by gen_zerohashes. DO NOT EDIT.
+package depositsnapshot
+
+var Zerohashes = [][32]byte{
+	// 0000000000000000000000000000000000000000000000000000000000000000
+	{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
+	// f5a5fd42d16a20302798ef6ed309979b43003d2320d9f0e8ea9831a92759fb4b
+	{245, 165, 253, 66, 209, 106, 32, 48, 39, 152, 239, 110, 211, 9, 151, 155, 67, 0, 61, 35, 32, 217, 240, 232, 234, 152, 49, 169, 39, 89, 251, 75},
+	// db56114e00fdd4c1f85c892bf35ac9a89289aaecb1ebd0a96cde606a748b5d71
+	{219, 86, 17, 78, 0, 253, 212, 193, 248, 92, 137, 43, 243, 90, 201, 168, 146, 137, 170, 236, 177, 235, 208, 169, 108, 222, 96, 106, 116, 139, 93, 113},
+	// c78009fdf07fc56a11f122370658a353aaa542ed63e44c4bc15ff4cd105ab33c
+	{199, 128, 9, 253, 240, 127, 197, 106, 17, 241, 34, 55, 6, 88, 163, 83, 170, 165, 66, 237, 99, 228, 76, 75, 193, 95, 244, 205, 16, 90, 179, 60},
+	// 536d98837f2dd165a55d5eeae91485954472d56f246df256bf3cae19352a123c
+	{83, 109, 152, 131, 127, 45, 209, 101, 165, 93, 94, 234, 233, 20, 133, 149, 68, 114, 213, 111, 36, 109, 242, 86, 191, 60, 174, 25, 53, 42, 18, 60},
+	// 9efde052aa15429fae05bad4d0b1d7c64da64d03d7a1854a588c2cb8430c0d30
+	{158, 253, 224, 82, 170, 21, 66, 159, 174, 5, 186, 212, 208, 177, 215, 198, 77, 166, 77, 3, 215, 161, 133, 74, 88, 140, 44, 184, 67, 12, 13, 48},
+	// d88ddfeed400a8755596b21942c1497e114c302e6118290f91e6772976041fa1
+	{216, 141, 223, 238, 212, 0, 168, 117, 85, 150, 178, 25, 66, 193, 73, 126, 17, 76, 48, 46, 97, 24, 41, 15, 145, 230, 119, 41, 118, 4, 31, 161},
+	// 87eb0ddba57e35f6d286673802a4af5975e22506c7cf4c64bb6be5ee11527f2c
+	{135, 235, 13, 219, 165, 126, 53, 246, 210, 134, 103, 56, 2, 164, 175, 89, 117, 226, 37, 6, 199, 207, 76, 100, 187, 107, 229, 238, 17, 82, 127, 44},
+	// 26846476fd5fc54a5d43385167c95144f2643f533cc85bb9d16b782f8d7db193
+	{38, 132, 100, 118, 253, 95, 197, 74, 93, 67, 56, 81, 103, 201, 81, 68, 242, 100, 63, 83, 60, 200, 91, 185, 209, 107, 120, 47, 141, 125, 177, 147},
+	// 506d86582d252405b840018792cad2bf1259f1ef5aa5f887e13cb2f0094f51e1
+	{80, 109, 134, 88, 45, 37, 36, 5, 184, 64, 1, 135, 146, 202, 210, 191, 18, 89, 241, 239, 90, 165, 248, 135, 225, 60, 178, 240, 9, 79, 81, 225},
+	// ffff0ad7e659772f9534c195c815efc4014ef1e1daed4404c06385d11192e92b
+	{255, 255, 10, 215, 230, 89, 119, 47, 149, 52, 193, 149, 200, 21, 239, 196, 1, 78, 241, 225, 218, 237, 68, 4, 192, 99, 133, 209, 17, 146, 233, 43},
+	// 6cf04127db05441cd833107a52be852868890e4317e6a02ab47683aa75964220
+	{108, 240, 65, 39, 219, 5, 68, 28, 216, 51, 16, 122, 82, 190, 133, 40, 104, 137, 14, 67, 23, 230, 160, 42, 180, 118, 131, 170, 117, 150, 66, 32},
+	// b7d05f875f140027ef5118a2247bbb84ce8f2f0f1123623085daf7960c329f5f
+	{183, 208, 95, 135, 95, 20, 0, 39, 239, 81, 24, 162, 36, 123, 187, 132, 206, 143, 47, 15, 17, 35, 98, 48, 133, 218, 247, 150, 12, 50, 159, 95},
+	// df6af5f5bbdb6be9ef8aa618e4bf8073960867171e29676f8b284dea6a08a85e
+	{223, 106, 245, 245, 187, 219, 107, 233, 239, 138, 166, 24, 228, 191, 128, 115, 150, 8, 103, 23, 30, 41, 103, 111, 139, 40, 77, 234, 106, 8, 168, 94},
+	// b58d900f5e182e3c50ef74969ea16c7726c549757cc23523c369587da7293784
+	{181, 141, 144, 15, 94, 24, 46, 60, 80, 239, 116, 150, 158, 161, 108, 119, 38, 197, 73, 117, 124, 194, 53, 35, 195, 105, 88, 125, 167, 41, 55, 132},
+	// d49a7502ffcfb0340b1d7885688500ca308161a7f96b62df9d083b71fcc8f2bb
+	{212, 154, 117, 2, 255, 207, 176, 52, 11, 29, 120, 133, 104, 133, 0, 202, 48, 129, 97, 167, 249, 107, 98, 223, 157, 8, 59, 113, 252, 200, 242, 187},
+	// 8fe6b1689256c0d385f42f5bbe2027a22c1996e110ba97c171d3e5948de92beb
+	{143, 230, 177, 104, 146, 86, 192, 211, 133, 244, 47, 91, 190, 32, 39, 162, 44, 25, 150, 225, 16, 186, 151, 193, 113, 211, 229, 148, 141, 233, 43, 235},
+	// 8d0d63c39ebade8509e0ae3c9c3876fb5fa112be18f905ecacfecb92057603ab
+	{141, 13, 99, 195, 158, 186, 222, 133, 9, 224, 174, 60, 156, 56, 118, 251, 95, 161, 18, 190, 24, 249, 5, 236, 172, 254, 203, 146, 5, 118, 3, 171},
+	// 95eec8b2e541cad4e91de38385f2e046619f54496c2382cb6cacd5b98c26f5a4
+	{149, 238, 200, 178, 229, 65, 202, 212, 233, 29, 227, 131, 133, 242, 224, 70, 97, 159, 84, 73, 108, 35, 130, 203, 108, 172, 213, 185, 140, 38, 245, 164},
+	// f893e908917775b62bff23294dbbe3a1cd8e6cc1c35b4801887b646a6f81f17f
+	{248, 147, 233, 8, 145, 119, 117, 182, 43, 255, 35, 41, 77, 187, 227, 161, 205, 142, 108, 193, 195, 91, 72, 1, 136, 123, 100, 106, 111, 129, 241, 127},
+	// cddba7b592e3133393c16194fac7431abf2f5485ed711db282183c819e08ebaa
+	{205, 219, 167, 181, 146, 227, 19, 51, 147, 193, 97, 148, 250, 199, 67, 26, 191, 47, 84, 133, 237, 113, 29, 178, 130, 24, 60, 129, 158, 8, 235, 170},
+	// 8a8d7fe3af8caa085a7639a832001457dfb9128a8061142ad0335629ff23ff9c
+	{138, 141, 127, 227, 175, 140, 170, 8, 90, 118, 57, 168, 50, 0, 20, 87, 223, 185, 18, 138, 128, 97, 20, 42, 208, 51, 86, 41, 255, 35, 255, 156},
+	// feb3c337d7a51a6fbf00b9e34c52e1c9195c969bd4e7a0bfd51d5c5bed9c1167
+	{254, 179, 195, 55, 215, 165, 26, 111, 191, 0, 185, 227, 76, 82, 225, 201, 25, 92, 150, 155, 212, 231, 160, 191, 213, 29, 92, 91, 237, 156, 17, 103},
+	// e71f0aa83cc32edfbefa9f4d3e0174ca85182eec9f3a09f6a6c0df6377a510d7
+	{231, 31, 10, 168, 60, 195, 46, 223, 190, 250, 159, 77, 62, 1, 116, 202, 133, 24, 46, 236, 159, 58, 9, 246, 166, 192, 223, 99, 119, 165, 16, 215},
+	// 31206fa80a50bb6abe29085058f16212212a60eec8f049fecb92d8c8e0a84bc0
+	{49, 32, 111, 168, 10, 80, 187, 106, 190, 41, 8, 80, 88, 241, 98, 18, 33, 42, 96, 238, 200, 240, 73, 254, 203, 146, 216, 200, 224, 168, 75, 192},
+	// 21352bfecbeddde993839f614c3dac0a3ee37543f9b412b16199dc158e23b544
+	{33, 53, 43, 254, 203, 237, 221, 233, 147, 131, 159, 97, 76, 61, 172, 10, 62, 227, 117, 67, 249, 180, 18, 177, 97, 153, 220, 21, 142, 35, 181, 68},
+	// 619e312724bb6d7c3153ed9de791d764a366b389af13c58bf8a8d90481a46765
+	{97, 158, 49, 39, 36, 187, 109, 124, 49, 83, 237, 157, 231, 145, 215, 100, 163, 102, 179, 137, 175, 19, 197, 139, 248, 168, 217, 4, 129, 164, 103, 101},
+	// 7cdd2986268250628d0c10e385c58c6191e6fbe05191bcc04f133f2cea72c1c4
+	{124, 221, 41, 134, 38, 130, 80, 98, 141, 12, 16, 227, 133, 197, 140, 97, 145, 230, 251, 224, 81, 145, 188, 192, 79, 19, 63, 44, 234, 114, 193, 196},
+	// 848930bd7ba8cac54661072113fb278869e07bb8587f91392933374d017bcbe1
+	{132, 137, 48, 189, 123, 168, 202, 197, 70, 97, 7, 33, 19, 251, 39, 136, 105, 224, 123, 184, 88, 127, 145, 57, 41, 51, 55, 77, 1, 123, 203, 225},
+	// 8869ff2c22b28cc10510d9853292803328be4fb0e80495e8bb8d271f5b889636
+	{136, 105, 255, 44, 34, 178, 140, 193, 5, 16, 217, 133, 50, 146, 128, 51, 40, 190, 79, 176, 232, 4, 149, 232, 187, 141, 39, 31, 91, 136, 150, 54},
+	// b5fe28e79f1b850f8658246ce9b6a1e7b49fc06db7143e8fe0b4f2b0c5523a5c
+	{181, 254, 40, 231, 159, 27, 133, 15, 134, 88, 36, 108, 233, 182, 161, 231, 180, 159, 192, 109, 183, 20, 62, 143, 224, 180, 242, 176, 197, 82, 58, 92},
+	// 985e929f70af28d0bdd1a90a808f977f597c7c778c489e98d3bd8910d31ac0f7
+	{152, 94, 146, 159, 112, 175, 40, 208, 189, 209, 169, 10, 128, 143, 151, 127, 89, 124, 124, 119, 140, 72, 158, 152, 211, 189, 137, 16, 211, 26, 192, 247},
+}
--- a/container/slice/slice.go
+++ b/container/slice/slice.go
@@ -382,3 +382,12 @@ func Unique[T comparable](a []T) []T {
 	}
 	return result[:end]
 }
+
+// Reverse reverses any slice in place
+// Taken from https://github.com/faiface/generics/blob/8cf65f0b43803410724d8c671cb4d328543ba07d/examples/sliceutils/sliceutils.go
+func Reverse[E any](s []E) []E {
+	for i, j := 0, len(s)-1; i < j; i, j = i+1, j-1 {
+		s[i], s[j] = s[j], s[i]
+	}
+	return s
+}
--- a/container/slice/slice_test.go
+++ b/container/slice/slice_test.go
@@ -599,3 +599,20 @@ func TestUnique(t *testing.T) {
 		require.DeepEqual(t, []uint64{1, 2}, result)
 	})
 }
+
+func TestReverse(t *testing.T) {
+	tests := []struct {
+		value [][32]byte
+		want  [][32]byte
+	}{
+		{[][32]byte{}, [][32]byte{}},
+		{[][32]byte{{'A'}, {'B'}, {'C'}, {'D'}},
+			[][32]byte{{'D'}, {'C'}, {'B'}, {'A'}}},
+		{[][32]byte{{1}, {2}, {3}, {4}},
+			[][32]byte{{4}, {3}, {2}, {1}}},
+	}
+	for _, tt := range tests {
+		b := slice.Reverse(tt.value)
+		require.DeepEqual(t, tt.want, b)
+	}
+}
--- a/encoding/bytesutil/integers.go
+++ b/encoding/bytesutil/integers.go
@@ -115,6 +115,14 @@ func Uint64ToBytesLittleEndian(i uint64) []byte {
 	return buf
 }

+// Uint64ToBytesLittleEndian32 conversion of a uint64 to a fix
+// sized 32 byte array in little endian order. Returns 32 byte array.
+func Uint64ToBytesLittleEndian32(i uint64) []byte {
+	buf := make([]byte, 32)
+	binary.LittleEndian.PutUint64(buf, i)
+	return buf
+}
+
 // Uint64ToBytesBigEndian conversion.
 func Uint64ToBytesBigEndian(i uint64) []byte {
 	buf := make([]byte, 8)
--- a/encoding/bytesutil/integers_test.go
+++ b/encoding/bytesutil/integers_test.go
@@ -300,3 +300,26 @@ func TestUint64ToBytesLittleEndian(t *testing.T) {
 		})
 	}
 }
+
+func TestUint64ToBytesLittleEndian32(t *testing.T) {
+	tests := []struct {
+		value uint64
+		want  [32]byte
+	}{
+		{
+			value: 0x01000000,
+			want:  [32]byte{0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
+		},
+		{
+			value: 0x00000001,
+			want:  [32]byte{1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(fmt.Sprintf("0x%08x", tt.value), func(t *testing.T) {
+			if got := bytesutil.Uint64ToBytesLittleEndian32(tt.value); !bytes.Equal(got, tt.want[:]) {
+				t.Errorf("Uint64ToBytesLittleEndian32() = got %v, want %v", got, tt.want)
+			}
+		})
+	}
+}