merkle

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Version: v0.31.5 Latest Latest
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Published: Apr 16, 2019 License: Apache-2.0 Imports: 14 Imported by: 0

README

Simple Merkle Tree

For smaller static data structures that don't require immutable snapshots or mutability; for instance the transactions and validation signatures of a block can be hashed using this simple merkle tree logic.

Documentation

Overview

Package merkle computes a deterministic minimal height Merkle tree hash. If the number of items is not a power of two, some leaves will be at different levels. Tries to keep both sides of the tree the same size, but the left may be one greater.

Use this for short deterministic trees, such as the validator list. For larger datasets, use IAVLTree.

Be aware that the current implementation by itself does not prevent second pre-image attacks. Hence, use this library with caution. Otherwise you might run into similar issues as, e.g., in early Bitcoin: https://bitcointalk.org/?topic=102395

              *
             / \
           /     \
         /         \
       /             \
      *               *
     / \             / \
    /   \           /   \
   /     \         /     \
  *       *       *       h6
 / \     / \     / \
h0  h1  h2  h3  h4  h5

TODO(ismail): add 2nd pre-image protection or clarify further on how we use this and why this secure.

Index

Constants

View Source
const (
	KeyEncodingURL keyEncoding = iota
	KeyEncodingHex
	KeyEncodingMax // Number of known encodings. Used for testing
)
View Source
const ProofOpSimpleValue = "simple:v"

Variables

View Source
var (
	ErrInvalidLengthMerkle = fmt.Errorf("proto: negative length found during unmarshaling")
	ErrIntOverflowMerkle   = fmt.Errorf("proto: integer overflow")
)

Functions

func KeyPathToKeys

func KeyPathToKeys(path string) (keys [][]byte, err error)

Decode a path to a list of keys. Path must begin with `/`. Each key must use a known encoding.

func SimpleHashFromByteSlices

func SimpleHashFromByteSlices(items [][]byte) []byte

SimpleHashFromByteSlices computes a Merkle tree where the leaves are the byte slice, in the provided order.

func SimpleHashFromMap

func SimpleHashFromMap(m map[string][]byte) []byte

SimpleHashFromMap computes a Merkle tree from sorted map. Like calling SimpleHashFromHashers with `item = []byte(Hash(key) | Hash(value))`, sorted by `item`.

func SimpleProofsFromMap

func SimpleProofsFromMap(m map[string][]byte) (rootHash []byte, proofs map[string]*SimpleProof, keys []string)

SimpleProofsFromMap generates proofs from a map. The keys/values of the map will be used as the keys/values in the underlying key-value pairs. The keys are sorted before the proofs are computed.

Types

type KVPair

type KVPair cmn.KVPair

A local extension to KVPair that can be hashed. Key and value are length prefixed and concatenated, then hashed.

func (KVPair) Bytes

func (kv KVPair) Bytes() []byte

Bytes returns key || value, with both the key and value length prefixed.

type Key

type Key struct {
	// contains filtered or unexported fields
}

type KeyPath

type KeyPath []Key

func (KeyPath) AppendKey

func (pth KeyPath) AppendKey(key []byte, enc keyEncoding) KeyPath

func (KeyPath) String

func (pth KeyPath) String() string

type OpDecoder

type OpDecoder func(ProofOp) (ProofOperator, error)

type Proof

type Proof struct {
	Ops                  []ProofOp `protobuf:"bytes,1,rep,name=ops" json:"ops"`
	XXX_NoUnkeyedLiteral struct{}  `json:"-"`
	XXX_unrecognized     []byte    `json:"-"`
	XXX_sizecache        int32     `json:"-"`
}

Proof is Merkle proof defined by the list of ProofOps

func NewPopulatedProof

func NewPopulatedProof(r randyMerkle, easy bool) *Proof

func (*Proof) Descriptor

func (*Proof) Descriptor() ([]byte, []int)

func (*Proof) Equal

func (this *Proof) Equal(that interface{}) bool

func (*Proof) GetOps

func (m *Proof) GetOps() []ProofOp

func (*Proof) Marshal

func (m *Proof) Marshal() (dAtA []byte, err error)

func (*Proof) MarshalTo

func (m *Proof) MarshalTo(dAtA []byte) (int, error)

func (*Proof) ProtoMessage

func (*Proof) ProtoMessage()

func (*Proof) Reset

func (m *Proof) Reset()

func (*Proof) Size

func (m *Proof) Size() (n int)

func (*Proof) String

func (m *Proof) String() string

func (*Proof) Unmarshal

func (m *Proof) Unmarshal(dAtA []byte) error

func (*Proof) XXX_DiscardUnknown

func (m *Proof) XXX_DiscardUnknown()

func (*Proof) XXX_Marshal

func (m *Proof) XXX_Marshal(b []byte, deterministic bool) ([]byte, error)

func (*Proof) XXX_Merge

func (dst *Proof) XXX_Merge(src proto.Message)

func (*Proof) XXX_Size

func (m *Proof) XXX_Size() int

func (*Proof) XXX_Unmarshal

func (m *Proof) XXX_Unmarshal(b []byte) error

type ProofOp

type ProofOp struct {
	Type                 string   `protobuf:"bytes,1,opt,name=type,proto3" json:"type,omitempty"`
	Key                  []byte   `protobuf:"bytes,2,opt,name=key,proto3" json:"key,omitempty"`
	Data                 []byte   `protobuf:"bytes,3,opt,name=data,proto3" json:"data,omitempty"`
	XXX_NoUnkeyedLiteral struct{} `json:"-"`
	XXX_unrecognized     []byte   `json:"-"`
	XXX_sizecache        int32    `json:"-"`
}

ProofOp defines an operation used for calculating Merkle root The data could be arbitrary format, providing nessecary data for example neighbouring node hash

func NewPopulatedProofOp

func NewPopulatedProofOp(r randyMerkle, easy bool) *ProofOp

func (*ProofOp) Descriptor

func (*ProofOp) Descriptor() ([]byte, []int)

func (*ProofOp) Equal

func (this *ProofOp) Equal(that interface{}) bool

func (*ProofOp) GetData

func (m *ProofOp) GetData() []byte

func (*ProofOp) GetKey

func (m *ProofOp) GetKey() []byte

func (*ProofOp) GetType

func (m *ProofOp) GetType() string

func (*ProofOp) Marshal

func (m *ProofOp) Marshal() (dAtA []byte, err error)

func (*ProofOp) MarshalTo

func (m *ProofOp) MarshalTo(dAtA []byte) (int, error)

func (*ProofOp) ProtoMessage

func (*ProofOp) ProtoMessage()

func (*ProofOp) Reset

func (m *ProofOp) Reset()

func (*ProofOp) Size

func (m *ProofOp) Size() (n int)

func (*ProofOp) String

func (m *ProofOp) String() string

func (*ProofOp) Unmarshal

func (m *ProofOp) Unmarshal(dAtA []byte) error

func (*ProofOp) XXX_DiscardUnknown

func (m *ProofOp) XXX_DiscardUnknown()

func (*ProofOp) XXX_Marshal

func (m *ProofOp) XXX_Marshal(b []byte, deterministic bool) ([]byte, error)

func (*ProofOp) XXX_Merge

func (dst *ProofOp) XXX_Merge(src proto.Message)

func (*ProofOp) XXX_Size

func (m *ProofOp) XXX_Size() int

func (*ProofOp) XXX_Unmarshal

func (m *ProofOp) XXX_Unmarshal(b []byte) error

type ProofOperator

type ProofOperator interface {
	Run([][]byte) ([][]byte, error)
	GetKey() []byte
	ProofOp() ProofOp
}

ProofOperator is a layer for calculating intermediate Merkle roots when a series of Merkle trees are chained together. Run() takes leaf values from a tree and returns the Merkle root for the corresponding tree. It takes and returns a list of bytes to allow multiple leaves to be part of a single proof, for instance in a range proof. ProofOp() encodes the ProofOperator in a generic way so it can later be decoded with OpDecoder.

func SimpleValueOpDecoder

func SimpleValueOpDecoder(pop ProofOp) (ProofOperator, error)

type ProofOperators

type ProofOperators []ProofOperator

ProofOperators is a slice of ProofOperator(s). Each operator will be applied to the input value sequentially and the last Merkle root will be verified with already known data

func (ProofOperators) Verify

func (poz ProofOperators) Verify(root []byte, keypath string, args [][]byte) (err error)

func (ProofOperators) VerifyValue

func (poz ProofOperators) VerifyValue(root []byte, keypath string, value []byte) (err error)

type ProofRuntime

type ProofRuntime struct {
	// contains filtered or unexported fields
}

func DefaultProofRuntime

func DefaultProofRuntime() (prt *ProofRuntime)

DefaultProofRuntime only knows about Simple value proofs. To use e.g. IAVL proofs, register op-decoders as defined in the IAVL package.

func NewProofRuntime

func NewProofRuntime() *ProofRuntime

func (*ProofRuntime) Decode

func (prt *ProofRuntime) Decode(pop ProofOp) (ProofOperator, error)

func (*ProofRuntime) DecodeProof

func (prt *ProofRuntime) DecodeProof(proof *Proof) (ProofOperators, error)

func (*ProofRuntime) RegisterOpDecoder

func (prt *ProofRuntime) RegisterOpDecoder(typ string, dec OpDecoder)

func (*ProofRuntime) Verify

func (prt *ProofRuntime) Verify(proof *Proof, root []byte, keypath string, args [][]byte) (err error)

func (*ProofRuntime) VerifyAbsence

func (prt *ProofRuntime) VerifyAbsence(proof *Proof, root []byte, keypath string) (err error)

TODO In the long run we'll need a method of classifcation of ops, whether existence or absence or perhaps a third?

func (*ProofRuntime) VerifyValue

func (prt *ProofRuntime) VerifyValue(proof *Proof, root []byte, keypath string, value []byte) (err error)

type SimpleProof

type SimpleProof struct {
	Total    int      `json:"total"`     // Total number of items.
	Index    int      `json:"index"`     // Index of item to prove.
	LeafHash []byte   `json:"leaf_hash"` // Hash of item value.
	Aunts    [][]byte `json:"aunts"`     // Hashes from leaf's sibling to a root's child.
}

SimpleProof represents a simple Merkle proof. NOTE: The convention for proofs is to include leaf hashes but to exclude the root hash. This convention is implemented across IAVL range proofs as well. Keep this consistent unless there's a very good reason to change everything. This also affects the generalized proof system as well.

func SimpleProofsFromByteSlices

func SimpleProofsFromByteSlices(items [][]byte) (rootHash []byte, proofs []*SimpleProof)

SimpleProofsFromByteSlices computes inclusion proof for given items. proofs[0] is the proof for items[0].

func (*SimpleProof) ComputeRootHash

func (sp *SimpleProof) ComputeRootHash() []byte

Compute the root hash given a leaf hash. Does not verify the result.

func (*SimpleProof) String

func (sp *SimpleProof) String() string

String implements the stringer interface for SimpleProof. It is a wrapper around StringIndented.

func (*SimpleProof) StringIndented

func (sp *SimpleProof) StringIndented(indent string) string

StringIndented generates a canonical string representation of a SimpleProof.

func (*SimpleProof) Verify

func (sp *SimpleProof) Verify(rootHash []byte, leaf []byte) error

Verify that the SimpleProof proves the root hash. Check sp.Index/sp.Total manually if needed

type SimpleProofNode

type SimpleProofNode struct {
	Hash   []byte
	Parent *SimpleProofNode
	Left   *SimpleProofNode // Left sibling  (only one of Left,Right is set)
	Right  *SimpleProofNode // Right sibling (only one of Left,Right is set)
}

SimpleProofNode is a helper structure to construct merkle proof. The node and the tree is thrown away afterwards. Exactly one of node.Left and node.Right is nil, unless node is the root, in which case both are nil. node.Parent.Hash = hash(node.Hash, node.Right.Hash) or hash(node.Left.Hash, node.Hash), depending on whether node is a left/right child.

func (*SimpleProofNode) FlattenAunts

func (spn *SimpleProofNode) FlattenAunts() [][]byte

FlattenAunts will return the inner hashes for the item corresponding to the leaf, starting from a leaf SimpleProofNode.

type SimpleValueOp

type SimpleValueOp struct {

	// To encode in ProofOp.Data
	Proof *SimpleProof `json:"simple_proof"`
	// contains filtered or unexported fields
}

SimpleValueOp takes a key and a single value as argument and produces the root hash. The corresponding tree structure is the SimpleMap tree. SimpleMap takes a Hasher, and currently Tendermint uses aminoHasher. SimpleValueOp should support the hash function as used in aminoHasher. TODO support additional hash functions here as options/args to this operator.

If the produced root hash matches the expected hash, the proof is good.

func NewSimpleValueOp

func NewSimpleValueOp(key []byte, proof *SimpleProof) SimpleValueOp

func (SimpleValueOp) GetKey

func (op SimpleValueOp) GetKey() []byte

func (SimpleValueOp) ProofOp

func (op SimpleValueOp) ProofOp() ProofOp

func (SimpleValueOp) Run

func (op SimpleValueOp) Run(args [][]byte) ([][]byte, error)

func (SimpleValueOp) String

func (op SimpleValueOp) String() string

type Tree

type Tree interface {
	Size() (size int)
	Height() (height int8)
	Has(key []byte) (has bool)
	Proof(key []byte) (value []byte, proof []byte, exists bool) // TODO make it return an index
	Get(key []byte) (index int, value []byte, exists bool)
	GetByIndex(index int) (key []byte, value []byte)
	Set(key []byte, value []byte) (updated bool)
	Remove(key []byte) (value []byte, removed bool)
	HashWithCount() (hash []byte, count int)
	Hash() (hash []byte)
	Save() (hash []byte)
	Load(hash []byte)
	Copy() Tree
	Iterate(func(key []byte, value []byte) (stop bool)) (stopped bool)
	IterateRange(start []byte, end []byte, ascending bool, fx func(key []byte, value []byte) (stop bool)) (stopped bool)
}

Tree is a Merkle tree interface.

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