You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
138 lines
4.0 KiB
138 lines
4.0 KiB
package merkle
|
|
|
|
import (
|
|
"bytes"
|
|
|
|
"github.com/pkg/errors"
|
|
)
|
|
|
|
//----------------------------------------
|
|
// ProofOp gets converted to an instance of ProofOperator:
|
|
|
|
// 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.
|
|
type ProofOperator interface {
|
|
Run([][]byte) ([][]byte, error)
|
|
GetKey() []byte
|
|
ProofOp() ProofOp
|
|
}
|
|
|
|
//----------------------------------------
|
|
// Operations on a list of ProofOperators
|
|
|
|
// 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
|
|
type ProofOperators []ProofOperator
|
|
|
|
func (poz ProofOperators) VerifyValue(root []byte, keypath string, value []byte) (err error) {
|
|
return poz.Verify(root, keypath, [][]byte{value})
|
|
}
|
|
|
|
func (poz ProofOperators) Verify(root []byte, keypath string, args [][]byte) (err error) {
|
|
keys, err := KeyPathToKeys(keypath)
|
|
if err != nil {
|
|
return
|
|
}
|
|
|
|
for i, op := range poz {
|
|
key := op.GetKey()
|
|
if len(key) != 0 {
|
|
if len(keys) == 0 {
|
|
return errors.Errorf("key path has insufficient # of parts: expected no more keys but got %+v", string(key))
|
|
}
|
|
lastKey := keys[len(keys)-1]
|
|
if !bytes.Equal(lastKey, key) {
|
|
return errors.Errorf("key mismatch on operation #%d: expected %+v but got %+v", i, string(lastKey), string(key))
|
|
}
|
|
keys = keys[:len(keys)-1]
|
|
}
|
|
args, err = op.Run(args)
|
|
if err != nil {
|
|
return
|
|
}
|
|
}
|
|
if !bytes.Equal(root, args[0]) {
|
|
return errors.Errorf("calculated root hash is invalid: expected %+v but got %+v", root, args[0])
|
|
}
|
|
if len(keys) != 0 {
|
|
return errors.New("keypath not consumed all")
|
|
}
|
|
return nil
|
|
}
|
|
|
|
//----------------------------------------
|
|
// ProofRuntime - main entrypoint
|
|
|
|
type OpDecoder func(ProofOp) (ProofOperator, error)
|
|
|
|
type ProofRuntime struct {
|
|
decoders map[string]OpDecoder
|
|
}
|
|
|
|
func NewProofRuntime() *ProofRuntime {
|
|
return &ProofRuntime{
|
|
decoders: make(map[string]OpDecoder),
|
|
}
|
|
}
|
|
|
|
func (prt *ProofRuntime) RegisterOpDecoder(typ string, dec OpDecoder) {
|
|
_, ok := prt.decoders[typ]
|
|
if ok {
|
|
panic("already registered for type " + typ)
|
|
}
|
|
prt.decoders[typ] = dec
|
|
}
|
|
|
|
func (prt *ProofRuntime) Decode(pop ProofOp) (ProofOperator, error) {
|
|
decoder := prt.decoders[pop.Type]
|
|
if decoder == nil {
|
|
return nil, errors.Errorf("unrecognized proof type %v", pop.Type)
|
|
}
|
|
return decoder(pop)
|
|
}
|
|
|
|
func (prt *ProofRuntime) DecodeProof(proof *Proof) (ProofOperators, error) {
|
|
poz := make(ProofOperators, 0, len(proof.Ops))
|
|
for _, pop := range proof.Ops {
|
|
operator, err := prt.Decode(pop)
|
|
if err != nil {
|
|
return nil, errors.Wrap(err, "decoding a proof operator")
|
|
}
|
|
poz = append(poz, operator)
|
|
}
|
|
return poz, nil
|
|
}
|
|
|
|
func (prt *ProofRuntime) VerifyValue(proof *Proof, root []byte, keypath string, value []byte) (err error) {
|
|
return prt.Verify(proof, root, keypath, [][]byte{value})
|
|
}
|
|
|
|
// TODO In the long run we'll need a method of classifcation of ops,
|
|
// whether existence or absence or perhaps a third?
|
|
func (prt *ProofRuntime) VerifyAbsence(proof *Proof, root []byte, keypath string) (err error) {
|
|
return prt.Verify(proof, root, keypath, nil)
|
|
}
|
|
|
|
func (prt *ProofRuntime) Verify(proof *Proof, root []byte, keypath string, args [][]byte) (err error) {
|
|
poz, err := prt.DecodeProof(proof)
|
|
if err != nil {
|
|
return errors.Wrap(err, "decoding proof")
|
|
}
|
|
return poz.Verify(root, keypath, args)
|
|
}
|
|
|
|
// DefaultProofRuntime only knows about Simple value
|
|
// proofs.
|
|
// To use e.g. IAVL proofs, register op-decoders as
|
|
// defined in the IAVL package.
|
|
func DefaultProofRuntime() (prt *ProofRuntime) {
|
|
prt = NewProofRuntime()
|
|
prt.RegisterOpDecoder(ProofOpSimpleValue, SimpleValueOpDecoder)
|
|
return
|
|
}
|