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Implement hdkeychain BIP0032 API.

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This commit adds a new sub-package named hdkeychain which can be used to
derive hierarchical deterministic key chains which form the foundation of
hd wallets.

- Support for private and public extended keys
- Convenient cryptographically secure seed generation
- Simple creation of master nodes
- Support for multi-layer derivation
- Easy serialization and deserialization for both private and public
  extended keys
- Support for custom networks by registering them with btcnet
- Obtaining the underlying EC pubkeys, EC privkeys, and associated bitcoin addresses
  ties in seamlessly with existing btcec and btcutil types which provide
  powerful tools for working with them to do things like sign transactions
  and generate payment scripts
- Makes use of the btcec package which is highly optimized for secp256k1
- Code examples including:
  - Generating a cryptographically secure random seed and deriving a
    master node from it
  - Default HD wallet layout as described by BIP0032
  - Audits use case as described by BIP0032
- Comprehensive test coverage including the BIP0032 test vectors
- Benchmarks
This commit is contained in:
Dave Collins 2014-07-19 02:13:00 -05:00
parent 4a3482182f
commit e6c5ca2a6a
8 changed files with 1650 additions and 0 deletions
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hdkeychain
==========
[![Build Status](https://travis-ci.org/conformal/btcutil.png?branch=master)]
(https://travis-ci.org/conformal/btcutil)
Package hdkeychain provides an API for bitcoin hierarchical deterministic
extended keys (BIP0032).
A comprehensive suite of tests is provided to ensure proper functionality. See
`test_coverage.txt` for the gocov coverage report. Alternatively, if you are
running a POSIX OS, you can run the `cov_report.sh` script for a real-time
report. Package hdkeychain is licensed under the liberal ISC license.
## Feature Overview
- Full BIP0032 implementation
- Single type for private and public extended keys
- Convenient cryptograpically secure seed generation
- Simple creation of master nodes
- Support for multi-layer derivation
- Easy serialization and deserialization for both private and public extended
keys
- Support for custom networks by registering them with btcnet
- Obtaining the underlying EC pubkeys, EC privkeys, and associated bitcoin
addresses ties in seamlessly with existing btcec and btcutil types which
provide powerful tools for working with them to do things like sign
transations and generate payment scripts
- Uses the btcec package which is highly optimized for secp256k1
- Code examples including:
- Generating a cryptographically secure random seed and deriving a
master node from it
- Default HD wallet layout as described by BIP0032
- Audits use case as described by BIP0032
- Comprehensive test coverage including the BIP0032 test vectors
- Benchmarks
## Documentation
[![GoDoc](https://godoc.org/github.com/conformal/btcutil/hdkeychain?status.png)]
(http://godoc.org/github.com/conformal/btcutil/hdkeychain)
Full `go doc` style documentation for the project can be viewed online without
installing this package by using the GoDoc site here:
http://godoc.org/github.com/conformal/btcutil/hdkeychain
You can also view the documentation locally once the package is installed with
the `godoc` tool by running `godoc -http=":6060"` and pointing your browser to
http://localhost:6060/pkg/github.com/conformal/btcutil/hdkeychain
## Installation
```bash
$ go get github.com/conformal/btcutil/hdkeychain
```
## Examples
* [NewMaster Example]
(http://godoc.org/github.com/conformal/btcutil/hdkeychain#example-NewMaster)
Demonstrates how to generate a cryptographically random seed then use it to
create a new master node (extended key).
* [Default Wallet Layout Example]
(http://godoc.org/github.com/conformal/btcutil/hdkeychain#example--defaultWalletLayout)
Demonstrates the default hierarchical deterministic wallet layout as described
in BIP0032.
* [Audits Use Case Example]
(http://godoc.org/github.com/conformal/btcutil/hdkeychain#example--audits)
Demonstrates the audits use case in BIP0032.
## License
Package hdkeychain is licensed under the [copyfree](http://copyfree.org) ISC
License.

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// Copyright (c) 2014 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package hdkeychain_test
import (
"testing"
"github.com/conformal/btcutil/hdkeychain"
)
// bip0032MasterPriv1 is the master private extended key from the first set of
// test vectors in BIP0032.
const bip0032MasterPriv1 = "xprv9s21ZrQH143K3QTDL4LXw2F7HEK3wJUD2nW2nRk4stbP" +
"y6cq3jPPqjiChkVvvNKmPGJxWUtg6LnF5kejMRNNU3TGtRBeJgk33yuGBxrMPHi"
// BenchmarkDeriveHardened benchmarks how long it takes to derive a hardened
// child from a master private extended key.
func BenchmarkDeriveHardened(b *testing.B) {
b.StopTimer()
masterKey, err := hdkeychain.NewKeyFromString(bip0032MasterPriv1)
if err != nil {
b.Errorf("Failed to decode master seed: %v", err)
}
b.StartTimer()
for i := 0; i < b.N; i++ {
masterKey.Child(hdkeychain.HardenedKeyStart)
}
}
// BenchmarkDeriveNormal benchmarks how long it takes to derive a normal
// (non-hardened) child from a master private extended key.
func BenchmarkDeriveNormal(b *testing.B) {
b.StopTimer()
masterKey, err := hdkeychain.NewKeyFromString(bip0032MasterPriv1)
if err != nil {
b.Errorf("Failed to decode master seed: %v", err)
}
b.StartTimer()
for i := 0; i < b.N; i++ {
masterKey.Child(0)
}
}
// BenchmarkPrivToPub benchmarks how long it takes to convert a private extended
// key to a public extended key.
func BenchmarkPrivToPub(b *testing.B) {
b.StopTimer()
masterKey, err := hdkeychain.NewKeyFromString(bip0032MasterPriv1)
if err != nil {
b.Errorf("Failed to decode master seed: %v", err)
}
b.StartTimer()
for i := 0; i < b.N; i++ {
masterKey.Neuter()
}
}
// BenchmarkDeserialize benchmarks how long it takes to deserialize a private
// extended key.
func BenchmarkDeserialize(b *testing.B) {
for i := 0; i < b.N; i++ {
hdkeychain.NewKeyFromString(bip0032MasterPriv1)
}
}
// BenchmarkSerialize benchmarks how long it takes to serialize a private
// extended key.
func BenchmarkSerialize(b *testing.B) {
b.StopTimer()
masterKey, err := hdkeychain.NewKeyFromString(bip0032MasterPriv1)
if err != nil {
b.Errorf("Failed to decode master seed: %v", err)
}
b.StartTimer()
for i := 0; i < b.N; i++ {
masterKey.String()
}
}

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#!/bin/sh
# This script uses gocov to generate a test coverage report.
# The gocov tool my be obtained with the following command:
# go get github.com/axw/gocov/gocov
#
# It will be installed to $GOPATH/bin, so ensure that location is in your $PATH.
# Check for gocov.
type gocov >/dev/null 2>&1
if [ $? -ne 0 ]; then
echo >&2 "This script requires the gocov tool."
echo >&2 "You may obtain it with the following command:"
echo >&2 "go get github.com/axw/gocov/gocov"
exit 1
fi
gocov test | gocov report

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// Copyright (c) 2014 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
/*
Package hdkeychain provides an API for bitcoin hierarchical deterministic
extended keys (BIP0032).
Overview
The ability to implement hierarchical deterministic wallets depends on the
ability to create and derive hierarchical deterministic extended keys.
At a high level, this package provides support for those hierarchical
deterministic extended keys by providing an ExtendedKey type and supporting
functions. Each extended key can either be a private or public extended key
which itself is capable of deriving a child extended key.
Determining the Extended Key Type
Whether an extended key is a private or public extended key can be determined
with the IsPrivate function.
Transaction Signing Keys and Payment Addresses
In order to create and sign transactions, or provide others with addresses to
send funds to, the underlying key and address material must be accessible. This
package provides the ECPubKey, ECPrivKey, and Address functions for this
purpose.
The Master Node
As previously mentioned, the extended keys are hierarchical meaning they are
used to form a tree. The root of that tree is called the master node and this
package provides the NewMaster function to create it from a cryptographically
random seed. The GenerateSeed function is provided as a convenient way to
create a random seed for use with the NewMaster function.
Deriving Children
Once you have created a tree root (or have deserialized an extended key as
discussed later), the child extended keys can be derived by using the Child
function. The Child function supports deriving both normal (non-hardened) and
hardened child extended keys. In order to derive a hardened extended key, use
the HardenedKeyStart constant + the hardened key number as the index to the
Child function. This provides the ability to cascade the keys into a tree and
hence generate the hierarchical deterministic key chains.
Normal vs Hardened Child Extended Keys
A private extended key can be used to derive both hardened and non-hardened
(normal) child private and public extended keys. A public extended key can only
be used to derive non-hardened child public extended keys. As enumerated in
BIP0032 "knowledge of the extended public key plus any non-hardened private key
descending from it is equivalent to knowing the extended private key (and thus
every private and public key descending from it). This means that extended
public keys must be treated more carefully than regular public keys. It is also
the reason for the existence of hardened keys, and why they are used for the
account level in the tree. This way, a leak of an account-specific (or below)
private key never risks compromising the master or other accounts."
Neutering a Private Extended Key
A private extended key can be converted to a new instance of the corresponding
public extended key with the Neuter function. The original extended key is not
modified. A public extended key is still capable of deriving non-hardened child
public extended keys.
Serializing and Deserializing Extended Keys
Extended keys are serialized and deserialized with the String and
NewKeyFromString functions. The serialized key is a Base58-encoded string which
looks like the following:
public key: xpub68Gmy5EdvgibQVfPdqkBBCHxA5htiqg55crXYuXoQRKfDBFA1WEjWgP6LHhwBZeNK1VTsfTFUHCdrfp1bgwQ9xv5ski8PX9rL2dZXvgGDnw
private key: xprv9uHRZZhk6KAJC1avXpDAp4MDc3sQKNxDiPvvkX8Br5ngLNv1TxvUxt4cV1rGL5hj6KCesnDYUhd7oWgT11eZG7XnxHrnYeSvkzY7d2bhkJ7
Network
Extended keys are much like normal Bitcoin addresses in that they have version
bytes which tie them to a specific network. The SetNet and IsForNet functions
are provided to set and determinine which network an extended key is associated
with.
*/
package hdkeychain

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// Copyright (c) 2014 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package hdkeychain_test
import (
"fmt"
"github.com/conformal/btcnet"
"github.com/conformal/btcutil/hdkeychain"
)
// This example demonstrates how to generate a cryptographically random seed
// then use it to create a new master node (extended key).
func ExampleNewMaster() {
// Generate a random seed at the recommended length.
seed, err := hdkeychain.GenerateSeed(hdkeychain.RecommendedSeedLen)
if err != nil {
fmt.Println(err)
return
}
// Generate a new master node using the seed.
key, err := hdkeychain.NewMaster(seed)
if err != nil {
fmt.Println(err)
return
}
// Show that the generated master node extended key is private.
fmt.Println("Private Extended Key?:", key.IsPrivate())
// Output:
// Private Extended Key?: true
}
// This example demonstrates the default hierarchical deterministic wallet
// layout as described in BIP0032.
func Example_defaultWalletLayout() {
// The default wallet layout described in BIP0032 is:
//
// Each account is composed of two keypair chains: an internal and an
// external one. The external keychain is used to generate new public
// addresses, while the internal keychain is used for all other
// operations (change addresses, generation addresses, ..., anything
// that doesn't need to be communicated).
//
// * m/iH/0/k
// corresponds to the k'th keypair of the external chain of account
// number i of the HDW derived from master m.
// * m/iH/1/k
// corresponds to the k'th keypair of the internal chain of account
// number i of the HDW derived from master m.
// Ordinarily this would either be read from some encrypted source
// and be decrypted or generated as the NewMaster example shows, but
// for the purposes of this example, the private exteded key for the
// master node is being hard coded here.
master := "xprv9s21ZrQH143K3QTDL4LXw2F7HEK3wJUD2nW2nRk4stbPy6cq3jP" +
"PqjiChkVvvNKmPGJxWUtg6LnF5kejMRNNU3TGtRBeJgk33yuGBxrMPHi"
// Start by getting an extended key instance for the master node.
// This gives the path:
// m
masterKey, err := hdkeychain.NewKeyFromString(master)
if err != nil {
fmt.Println(err)
return
}
// Derive the extended key for account 0. This gives the path:
// m/0H
acct0, err := masterKey.Child(hdkeychain.HardenedKeyStart + 0)
if err != nil {
fmt.Println(err)
return
}
// Derive the extended key for the account 0 external chain. This
// gives the path:
// m/0H/0
acct0Ext, err := acct0.Child(0)
if err != nil {
fmt.Println(err)
return
}
// Derive the extended key for the account 0 internal chain. This gives
// the path:
// m/0H/1
acct0Int, err := acct0.Child(1)
if err != nil {
fmt.Println(err)
return
}
// At this point, acct0Ext and acct0Int are ready to derive the keys for
// the external and internal wallet chains.
// Derive the 10th extended key for the account 0 external chain. This
// gives the path:
// m/0H/0/10
acct0Ext10, err := acct0Ext.Child(10)
if err != nil {
fmt.Println(err)
return
}
// Derive the 1st extended key for the account 0 internal chain. This
// gives the path:
// m/0H/1/0
acct0Int0, err := acct0Int.Child(0)
if err != nil {
fmt.Println(err)
return
}
// Get and show the address associated with the extended keys for the
// main bitcoin network.
acct0ExtAddr, err := acct0Ext10.Address(&btcnet.MainNetParams)
if err != nil {
fmt.Println(err)
return
}
acct0IntAddr, err := acct0Int0.Address(&btcnet.MainNetParams)
if err != nil {
fmt.Println(err)
return
}
fmt.Println("Account 0 External Address 10:", acct0ExtAddr)
fmt.Println("Account 0 Internal Address 0:", acct0IntAddr)
// Output:
// Account 0 External Address 10: 1HVccubUT8iKTapMJ5AnNA4sLRN27xzQ4F
// Account 0 Internal Address 0: 1J5rebbkQaunJTUoNVREDbeB49DqMNFFXk
}
// This example demonstrates the audits use case in BIP0032.
func Example_audits() {
// The audits use case described in BIP0032 is:
//
// In case an auditor needs full access to the list of incoming and
// outgoing payments, one can share all account public extended keys.
// This will allow the auditor to see all transactions from and to the
// wallet, in all accounts, but not a single secret key.
//
// * N(m/*)
// corresponds to the neutered master extended key (also called
// the master public extended key)
// Ordinarily this would either be read from some encrypted source
// and be decrypted or generated as the NewMaster example shows, but
// for the purposes of this example, the private exteded key for the
// master node is being hard coded here.
master := "xprv9s21ZrQH143K3QTDL4LXw2F7HEK3wJUD2nW2nRk4stbPy6cq3jP" +
"PqjiChkVvvNKmPGJxWUtg6LnF5kejMRNNU3TGtRBeJgk33yuGBxrMPHi"
// Start by getting an extended key instance for the master node.
// This gives the path:
// m
masterKey, err := hdkeychain.NewKeyFromString(master)
if err != nil {
fmt.Println(err)
return
}
// Neuter the master key to generate a master public extended key. This
// gives the path:
// N(m/*)
masterPubKey, err := masterKey.Neuter()
if err != nil {
fmt.Println(err)
return
}
// Share the master public extended key with the auditor.
fmt.Println("Audit key N(m/*):", masterPubKey)
// Output:
// Audit key N(m/*): xpub661MyMwAqRbcFtXgS5sYJABqqG9YLmC4Q1Rdap9gSE8NqtwybGhePY2gZ29ESFjqJoCu1Rupje8YtGqsefD265TMg7usUDFdp6W1EGMcet8
}

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// Copyright (c) 2014 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package hdkeychain
// References:
// [BIP32]: BIP0032 - Hierarchical Deterministic Wallets
// https://github.com/bitcoin/bips/blob/master/bip-0032.mediawiki
import (
"bytes"
"crypto/hmac"
"crypto/rand"
"crypto/sha512"
"encoding/binary"
"errors"
"fmt"
"math/big"
"github.com/conformal/btcec"
"github.com/conformal/btcnet"
"github.com/conformal/btcutil"
"github.com/conformal/btcwire"
)
const (
// RecommendedSeedLen is the recommended length in bytes for a seed
// to a master node.
RecommendedSeedLen = 32 // 256 bits
// HardenedKeyStart is the index at which a hardended key starts. Each
// extended key has 2^31 normal child keys and 2^31 hardned child keys.
// Thus the range for normal child keys is [0, 2^31 - 1] and the range
// for hardened child keys is [2^31, 2^32 - 1].
HardenedKeyStart = 0x80000000 // 2^31
// minSeedBytes is the minimum number of bytes allowed for a seed to
// a master node.
minSeedBytes = 16 // 128 bits
// maxSeedBytes is the maximum number of bytes allowed for a seed to
// a master node.
maxSeedBytes = 64 // 512 bits
// serializedKeyLen is the length of a serialized public or private
// extended key. It consists of 4 bytes version, 1 byte depth, 4 bytes
// fingerprint, 4 bytes child number, 32 bytes chain code, and 33 bytes
// public/private key data.
serializedKeyLen = 4 + 1 + 4 + 4 + 32 + 33 // 78 bytes
)
var (
// ErrDeriveHardFromPublic describes an error in which the caller
// attempted to derive a hardened extended key from a public key.
ErrDeriveHardFromPublic = errors.New("cannot derive a hardened key " +
"from a public key")
// ErrNotPrivExtKey describes an error in which the caller attempted
// to extract a private key from a public extended key.
ErrNotPrivExtKey = errors.New("unable to create private keys from a " +
"public extended key")
// ErrInvalidChild describes an error in which the child at a specific
// index is invalid due to the derived key falling outside of the valid
// range for secp256k1 private keys. This error indicates the caller
// should simply ignore the invalid child extended key at this index and
// increment to the next index.
ErrInvalidChild = errors.New("the extended key at this index is invalid")
// ErrUnusableSeed describes an error in which the provided seed is not
// usable due to the derived key falling outside of the valid range for
// secp256k1 private keys. This error indicates the caller must choose
// another seed.
ErrUnusableSeed = errors.New("unusable seed")
// ErrInvalidSeedLen describes an error in which the provided seed or
// seed length is not in the allowed range.
ErrInvalidSeedLen = fmt.Errorf("seed length must be between %d and %d "+
"bits", minSeedBytes*8, maxSeedBytes*8)
// ErrBadChecksum describes an error in which the checksum encoded with
// a serialized extended key does not match the calculated value.
ErrBadChecksum = errors.New("bad extended key checksum")
// ErrInvalidKeyLen describes an error in which the provided serialized
// key is not the expected length.
ErrInvalidKeyLen = errors.New("the provided serialized extended key " +
"length is invalid")
)
// masterKey is the master key used along with a random seed used to generate
// the master node in the hierarchical tree.
var masterKey = []byte("Bitcoin seed")
// ExtendedKey houses all the information needed to support a hierarchical
// deterministic extended key. See the package overview documentation for
// more details on how to use extended keys.
type ExtendedKey struct {
key []byte // This will be the pubkey for extended pub keys
pubKey []byte // This will only be set for extended priv keys
chainCode []byte
depth uint16
parentFP []byte
childNum uint32
version []byte
isPrivate bool
}
// newExtendedKey returns a new instance of an extended key with the given
// fields. No error checking is performed here as it's only intended to be a
// convenience method used to create a populated struct.
func newExtendedKey(version, key, chainCode, parentFP []byte, depth uint16,
childNum uint32, isPrivate bool) *ExtendedKey {
// NOTE: The pubKey field is intentionally left nil so it is only
// computed and memoized as required.
return &ExtendedKey{
key: key,
chainCode: chainCode,
depth: depth,
parentFP: parentFP,
childNum: childNum,
version: version,
isPrivate: isPrivate,
}
}
// pubKeyBytes returns bytes for the serialized compressed public key associated
// with this extended key in an efficient manner including memoization as
// necessary.
//
// When the extended key is already a public key, the key is simply returned as
// is since it's already in the correct form. However, when the extended key is
// a private key, the public key will be calculated and memoized so future
// accesses can simply return the cached result.
func (k *ExtendedKey) pubKeyBytes() []byte {
// Just return the key if it's already an extended public key.
if !k.isPrivate {
return k.key
}
// This is a private extended key, so calculate and memoize the public
// key if needed.
if len(k.pubKey) == 0 {
pkx, pky := btcec.S256().ScalarBaseMult(k.key)
pubKey := btcec.PublicKey{Curve: btcec.S256(), X: pkx, Y: pky}
k.pubKey = pubKey.SerializeCompressed()
}
return k.pubKey
}
// IsPrivate returns whether or not the extended key is a private extended key.
//
// A private extended key can be used to derive both hardened and non-hardened
// child private and public extended keys. A public extended key can only be
// used to derive non-hardened child public extended keys.
func (k *ExtendedKey) IsPrivate() bool {
return k.isPrivate
}
// ParentFingerprint returns a fingerprint of the parent extended key from which
// this one was derived.
func (k *ExtendedKey) ParentFingerprint() uint32 {
return binary.BigEndian.Uint32(k.parentFP)
}
// Child returns a derived child extended key at the given index. When this
// extended key is a private extended key (as determined by the IsPrivate
// function), a private extended key will be derived. Otherwise, the derived
// extended key will be also be a public extended key.
//
// When the index is greater to or equal than the HardenedKeyStart constant, the
// derived extended key will be a hardened extended key. It is only possible to
// derive a hardended extended key from a private extended key. Consequently,
// this function will return ErrDeriveHardFromPublic if a hardened child
// extended key is requested from a public extended key.
//
// A hardened extended key is useful since, as previously mentioned, it requires
// a parent private extended key to derive. In other words, normal child
// extended public keys can be derived from a parent public extended key (no
// knowledge of the parent private key) whereas hardened extended keys may not
// be.
//
// NOTE: There is an extremely small chance (< 1 in 2^127) the specific child
// index does not derive to a usable child. The ErrInvalidChild error will be
// returned if this should occur, and the caller is expected to ignore the
// invalid child and simply increment to the next index.
func (k *ExtendedKey) Child(i uint32) (*ExtendedKey, error) {
// There are four scenarios that could happen here:
// 1) Private extended key -> Hardened child private extended key
// 2) Private extended key -> Non-hardened child private extended key
// 3) Public extended key -> Non-hardened child public extended key
// 4) Public extended key -> Hardened child public extended key (INVALID!)
// Case #4 is invalid, so error out early.
// A hardened child extended key may not be created from a public
// extended key.
isChildHardened := i >= HardenedKeyStart
if !k.isPrivate && isChildHardened {
return nil, ErrDeriveHardFromPublic
}
// The data used to derive the child key depends on whether or not the
// child is hardened per [BIP32].
//
// For hardened children:
// 0x00 || ser256(parentKey) || ser32(i)
//
// For normal children:
// serP(parentPubKey) || ser32(i)
keyLen := 33
data := make([]byte, keyLen+4)
if isChildHardened {
// Case #1.
// When the child is a hardened child, the key is known to be a
// private key due to the above early return. Pad it with a
// leading zero as required by [BIP32] for deriving the child.
copy(data[1:], k.key)
} else {
// Case #2 or #3.
// This is either a public or private extended key, but in
// either case, the data which is used to derive the child key
// starts with the secp256k1 compressed public key bytes.
copy(data, k.pubKeyBytes())
}
binary.BigEndian.PutUint32(data[keyLen:], i)
// Take the HMAC-SHA512 of the current key's chain code and the derived
// data:
// I = HMAC-SHA512(Key = chainCode, Data = data)
hmac512 := hmac.New(sha512.New, k.chainCode)
hmac512.Write(data)
ilr := hmac512.Sum(nil)
// Split "I" into two 32-byte sequences Il and Ir where:
// Il = intermediate key used to derive the child
// Ir = child chain code
il := ilr[:len(ilr)/2]
childChainCode := ilr[len(ilr)/2:]
// Both derived public or private keys rely on treating the left 32-byte
// sequence calculated above (Il) as a 256-bit integer that must be
// within the valid range for a secp256k1 private key. There is a small
// chance (< 1 in 2^127) this condition will not hold, and in that case,
// a child extended key can't be created for this index and the caller
// should simply increment to the next index.
ilNum := new(big.Int).SetBytes(il)
if ilNum.Cmp(btcec.S256().N) >= 0 || ilNum.Sign() == 0 {
return nil, ErrInvalidChild
}
// The algorithm used to derive the child key depends on whether or not
// a private or public child is being derived.
//
// For private children:
// childKey = parse256(Il) + parentKey
//
// For public children:
// childKey = serP(point(parse256(Il)) + parentKey)
var isPrivate bool
var childKey []byte
if k.isPrivate {
// Case #1 or #2.
// Add the parent private key to the intermediate private key to
// derive the final child key.
//
// childKey = parse256(Il) + parenKey
keyNum := new(big.Int).SetBytes(k.key)
ilNum.Add(ilNum, keyNum)
ilNum.Mod(ilNum, btcec.S256().N)
childKey = ilNum.Bytes()
isPrivate = true
} else {
// Case #3.
// Calculate the corresponding intermediate public key for
// intermediate private key.
ilx, ily := btcec.S256().ScalarBaseMult(il)
if ilx.Sign() == 0 || ily.Sign() == 0 {
return nil, ErrInvalidChild
}
// Convert the serialized compressed parent public key into X
// and Y coordinates so it can be added to the intermediate
// public key.
pubKey, err := btcec.ParsePubKey(k.key, btcec.S256())
if err != nil {
return nil, err
}
// Add the intermediate public key to the parent public key to
// derive the final child key.
//
// childKey = serP(point(parse256(Il)) + parentKey)
childX, childY := btcec.S256().Add(ilx, ily, pubKey.X, pubKey.Y)
pk := btcec.PublicKey{Curve: btcec.S256(), X: childX, Y: childY}
childKey = pk.SerializeCompressed()
}
// The fingerprint of the parent for the derived child is the first 4
// bytes of the RIPEMD160(SHA256(parentPubKey)).
parentFP := btcutil.Hash160(k.pubKeyBytes())[:4]
return newExtendedKey(k.version, childKey, childChainCode, parentFP,
k.depth+1, i, isPrivate), nil
}
// Neuter returns a new extended public key from this extended private key. The
// same extended key will be returned unaltered if it is already an extended
// public key.
//
// As the name implies, an extended public key does not have access to the
// private key, so it is not capable of signing transactions or deriving
// child extended private keys. However, it is capable of deriving further
// child extended public keys.
func (k *ExtendedKey) Neuter() (*ExtendedKey, error) {
// Already an extended public key.
if !k.isPrivate {
return k, nil
}
// Get the associated public extended key version bytes.
version, err := btcnet.HDPrivateKeyToPublicKeyID(k.version)
if err != nil {
return nil, err
}
// Convert it to an extended public key. The key for the new extended
// key will simply be the pubkey of the current extended private key.
//
// This is the function N((k,c)) -> (K, c) from [BIP32].
return newExtendedKey(version, k.pubKeyBytes(), k.chainCode, k.parentFP,
k.depth, k.childNum, false), nil
}
// ECPubKey converts the extended key to a btcec public key and returns it.
func (k *ExtendedKey) ECPubKey() (*btcec.PublicKey, error) {
return btcec.ParsePubKey(k.pubKeyBytes(), btcec.S256())
}
// ECPrivKey converts the extended key to a btcec private key and returns it.
// As you might imagine this is only possible if the extended key is a private
// extended key (as determined by the IsPrivate function). The ErrNotPrivExtKey
// error will be returned if this function is called on a public extended key.
func (k *ExtendedKey) ECPrivKey() (*btcec.PrivateKey, error) {
if !k.isPrivate {
return nil, ErrNotPrivExtKey
}
privKey, _ := btcec.PrivKeyFromBytes(btcec.S256(), k.key)
return privKey, nil
}
// Address converts the extended key to a standard bitcoin pay-to-pubkey-hash
// address for the passed network.
func (k *ExtendedKey) Address(net *btcnet.Params) (*btcutil.AddressPubKeyHash, error) {
pkHash := btcutil.Hash160(k.pubKeyBytes())
return btcutil.NewAddressPubKeyHash(pkHash, net)
}
// String returns the extended key as a human-readable base58-encoded string.
func (k *ExtendedKey) String() string {
var childNumBytes [4]byte
depthByte := byte(k.depth % 256)
binary.BigEndian.PutUint32(childNumBytes[:], k.childNum)
// The serialized format is:
// version (4) || depth (1) || parent fingerprint (4)) ||
// child num (4) || chain code (32) || key data (33) || checksum (4)
serializedBytes := make([]byte, 0, serializedKeyLen+4)
serializedBytes = append(serializedBytes, k.version...)
serializedBytes = append(serializedBytes, depthByte)
serializedBytes = append(serializedBytes, k.parentFP...)
serializedBytes = append(serializedBytes, childNumBytes[:]...)
serializedBytes = append(serializedBytes, k.chainCode...)
if k.isPrivate {
serializedBytes = append(serializedBytes, 0x00)
serializedBytes = append(serializedBytes, k.key...)
} else {
serializedBytes = append(serializedBytes, k.pubKeyBytes()...)
}
checkSum := btcwire.DoubleSha256(serializedBytes)[:4]
serializedBytes = append(serializedBytes, checkSum...)
return btcutil.Base58Encode(serializedBytes)
}
// IsForNet returns whether or not the extended key is associated with the
// passed bitcoin network.
func (k *ExtendedKey) IsForNet(net *btcnet.Params) bool {
return bytes.Equal(k.version, net.HDPrivateKeyID[:]) ||
bytes.Equal(k.version, net.HDPublicKeyID[:])
}
// SetNet associates the extended key, and any child keys yet to be derived from
// it, with the passed network.
func (k *ExtendedKey) SetNet(net *btcnet.Params) {
if k.isPrivate {
k.version = net.HDPrivateKeyID[:]
} else {
k.version = net.HDPublicKeyID[:]
}
}
// NewMaster creates a new master node for use in creating a hierarchical
// deterministic key chain. The seed must be between 128 and 512 bits and
// should be generated by a cryptographically secure random generation source.
//
// NOTE: There is an extremely small chance (< 1 in 2^127) the provided seed
// will derive to an unusable secret key. The ErrUnusable error will be
// returned if this should occur, so the caller must check for it and generate a
// new seed accordingly.
func NewMaster(seed []byte) (*ExtendedKey, error) {
// Per [BIP32], the seed must be in range [minSeedBytes, maxSeedBytes].
if len(seed) < minSeedBytes || len(seed) > maxSeedBytes {
return nil, ErrInvalidSeedLen
}
// First take the HMAC-SHA512 of the master key and the seed data:
// I = HMAC-SHA512(Key = "Bitcoin seed", Data = S)
hmac512 := hmac.New(sha512.New, masterKey)
hmac512.Write(seed)
lr := hmac512.Sum(nil)
// Split "I" into two 32-byte sequences Il and Ir where:
// Il = master secret key
// Ir = master chain code
secretKey := lr[:len(lr)/2]
chainCode := lr[len(lr)/2:]
// Ensure the key in usable.
secretKeyNum := new(big.Int).SetBytes(secretKey)
if secretKeyNum.Cmp(btcec.S256().N) >= 0 || secretKeyNum.Sign() == 0 {
return nil, ErrUnusableSeed
}
parentFP := []byte{0x00, 0x00, 0x00, 0x00}
return newExtendedKey(btcnet.MainNetParams.HDPrivateKeyID[:], secretKey,
chainCode, parentFP, 0, 0, true), nil
}
// NewKeyFromString returns a new extended key instance from a base58-encoded
// extended key.
func NewKeyFromString(key string) (*ExtendedKey, error) {
// The base58-decoded extended key must consist of a serialized payload
// plus an additional 4 bytes for the checksum.
decoded := btcutil.Base58Decode(key)
if len(decoded) != serializedKeyLen+4 {
return nil, ErrInvalidKeyLen
}
// The serialized format is:
// version (4) || depth (1) || parent fingerprint (4)) ||
// child num (4) || chain code (32) || key data (33) || checksum (4)
// Split the payload and checksum up and ensure the checksum matches.
payload := decoded[:len(decoded)-4]
checkSum := decoded[len(decoded)-4:]
expectedCheckSum := btcwire.DoubleSha256(payload)[:4]
if !bytes.Equal(checkSum, expectedCheckSum) {
return nil, ErrBadChecksum
}
// Deserialize each of the payload fields.
version := payload[:4]
depth := uint16(payload[4:5][0])
parentFP := payload[5:9]
childNum := binary.BigEndian.Uint32(payload[9:13])
chainCode := payload[13:45]
keyData := payload[45:78]
// The key data is a private key if it starts with 0x00. Serialized
// compressed pubkeys either start with 0x02 or 0x03.
isPrivate := keyData[0] == 0x00
if isPrivate {
// Ensure the private key is valid. It must be within the range
// of the order of the secp256k1 curve and not be 0.
keyData = keyData[1:]
keyNum := new(big.Int).SetBytes(keyData)
if keyNum.Cmp(btcec.S256().N) >= 0 || keyNum.Sign() == 0 {
return nil, ErrUnusableSeed
}
} else {
// Ensure the public key parses correctly and is actually on the
// secp256k1 curve.
_, err := btcec.ParsePubKey(keyData, btcec.S256())
if err != nil {
return nil, err
}
}
return newExtendedKey(version, keyData, chainCode, parentFP, depth,
childNum, isPrivate), nil
}
// GenerateSeed returns a cryptographically secure random seed that can be used
// as the input for the NewMaster function to generate a new master node.
//
// The length is in bytes and it must be between 16 and 64 (128 to 512 bits).
// The recommended length is 32 (256 bits) as defined by the RecommendedSeedLen
// constant.
func GenerateSeed(length uint8) ([]byte, error) {
// Per [BIP32], the seed must be in range [minSeedBytes, maxSeedBytes].
if length < minSeedBytes || length > maxSeedBytes {
return nil, ErrInvalidSeedLen
}
buf := make([]byte, length)
_, err := rand.Read(buf)
if err != nil {
return nil, err
}
return buf, nil
}

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hdkeychain/extendedkey_test.go Normal file
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@ -0,0 +1,676 @@
// Copyright (c) 2014 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package hdkeychain_test
// References:
// [BIP32]: BIP0032 - Hierarchical Deterministic Wallets
// https://github.com/bitcoin/bips/blob/master/bip-0032.mediawiki
import (
"bytes"
"encoding/hex"
"errors"
"reflect"
"testing"
"github.com/conformal/btcnet"
"github.com/conformal/btcutil/hdkeychain"
)
// TestBIP0032Vectors tests the vectors provided by [BIP32] to ensure the
// derivation works as intended.
func TestBIP0032Vectors(t *testing.T) {
// The master seeds for each of the two test vectors in [BIP32].
testVec1MasterHex := "000102030405060708090a0b0c0d0e0f"
testVec2MasterHex := "fffcf9f6f3f0edeae7e4e1dedbd8d5d2cfccc9c6c3c0bdbab7b4b1aeaba8a5a29f9c999693908d8a8784817e7b7875726f6c696663605d5a5754514e4b484542"
hkStart := uint32(0x80000000)
var tests = []struct {
name string
master string
path []uint32
wantPub string
wantPriv string
}{
// Test vector 1
{
name: "test vector 1 chain m",
master: testVec1MasterHex,
path: []uint32{},
wantPub: "xpub661MyMwAqRbcFtXgS5sYJABqqG9YLmC4Q1Rdap9gSE8NqtwybGhePY2gZ29ESFjqJoCu1Rupje8YtGqsefD265TMg7usUDFdp6W1EGMcet8",
wantPriv: "xprv9s21ZrQH143K3QTDL4LXw2F7HEK3wJUD2nW2nRk4stbPy6cq3jPPqjiChkVvvNKmPGJxWUtg6LnF5kejMRNNU3TGtRBeJgk33yuGBxrMPHi",
},
{
name: "test vector 1 chain m/0H",
master: testVec1MasterHex,
path: []uint32{hkStart},
wantPub: "xpub68Gmy5EdvgibQVfPdqkBBCHxA5htiqg55crXYuXoQRKfDBFA1WEjWgP6LHhwBZeNK1VTsfTFUHCdrfp1bgwQ9xv5ski8PX9rL2dZXvgGDnw",
wantPriv: "xprv9uHRZZhk6KAJC1avXpDAp4MDc3sQKNxDiPvvkX8Br5ngLNv1TxvUxt4cV1rGL5hj6KCesnDYUhd7oWgT11eZG7XnxHrnYeSvkzY7d2bhkJ7",
},
{
name: "test vector 1 chain m/0H/1",
master: testVec1MasterHex,
path: []uint32{hkStart, 1},
wantPub: "xpub6ASuArnXKPbfEwhqN6e3mwBcDTgzisQN1wXN9BJcM47sSikHjJf3UFHKkNAWbWMiGj7Wf5uMash7SyYq527Hqck2AxYysAA7xmALppuCkwQ",
wantPriv: "xprv9wTYmMFdV23N2TdNG573QoEsfRrWKQgWeibmLntzniatZvR9BmLnvSxqu53Kw1UmYPxLgboyZQaXwTCg8MSY3H2EU4pWcQDnRnrVA1xe8fs",
},
{
name: "test vector 1 chain m/0H/1/2H",
master: testVec1MasterHex,
path: []uint32{hkStart, 1, hkStart + 2},
wantPub: "xpub6D4BDPcP2GT577Vvch3R8wDkScZWzQzMMUm3PWbmWvVJrZwQY4VUNgqFJPMM3No2dFDFGTsxxpG5uJh7n7epu4trkrX7x7DogT5Uv6fcLW5",
wantPriv: "xprv9z4pot5VBttmtdRTWfWQmoH1taj2axGVzFqSb8C9xaxKymcFzXBDptWmT7FwuEzG3ryjH4ktypQSAewRiNMjANTtpgP4mLTj34bhnZX7UiM",
},
{
name: "test vector 1 chain m/0H/1/2H/2",
master: testVec1MasterHex,
path: []uint32{hkStart, 1, hkStart + 2, 2},
wantPub: "xpub6FHa3pjLCk84BayeJxFW2SP4XRrFd1JYnxeLeU8EqN3vDfZmbqBqaGJAyiLjTAwm6ZLRQUMv1ZACTj37sR62cfN7fe5JnJ7dh8zL4fiyLHV",
wantPriv: "xprvA2JDeKCSNNZky6uBCviVfJSKyQ1mDYahRjijr5idH2WwLsEd4Hsb2Tyh8RfQMuPh7f7RtyzTtdrbdqqsunu5Mm3wDvUAKRHSC34sJ7in334",
},
{
name: "test vector 1 chain m/0H/1/2H/2/1000000000",
master: testVec1MasterHex,
path: []uint32{hkStart, 1, hkStart + 2, 2, 1000000000},
wantPub: "xpub6H1LXWLaKsWFhvm6RVpEL9P4KfRZSW7abD2ttkWP3SSQvnyA8FSVqNTEcYFgJS2UaFcxupHiYkro49S8yGasTvXEYBVPamhGW6cFJodrTHy",
wantPriv: "xprvA41z7zogVVwxVSgdKUHDy1SKmdb533PjDz7J6N6mV6uS3ze1ai8FHa8kmHScGpWmj4WggLyQjgPie1rFSruoUihUZREPSL39UNdE3BBDu76",
},
// Test vector 2
{
name: "test vector 2 chain m",
master: testVec2MasterHex,
path: []uint32{},
wantPub: "xpub661MyMwAqRbcFW31YEwpkMuc5THy2PSt5bDMsktWQcFF8syAmRUapSCGu8ED9W6oDMSgv6Zz8idoc4a6mr8BDzTJY47LJhkJ8UB7WEGuduB",
wantPriv: "xprv9s21ZrQH143K31xYSDQpPDxsXRTUcvj2iNHm5NUtrGiGG5e2DtALGdso3pGz6ssrdK4PFmM8NSpSBHNqPqm55Qn3LqFtT2emdEXVYsCzC2U",
},
{
name: "test vector 2 chain m/0",
master: testVec2MasterHex,
path: []uint32{0},
wantPub: "xpub69H7F5d8KSRgmmdJg2KhpAK8SR3DjMwAdkxj3ZuxV27CprR9LgpeyGmXUbC6wb7ERfvrnKZjXoUmmDznezpbZb7ap6r1D3tgFxHmwMkQTPH",
wantPriv: "xprv9vHkqa6EV4sPZHYqZznhT2NPtPCjKuDKGY38FBWLvgaDx45zo9WQRUT3dKYnjwih2yJD9mkrocEZXo1ex8G81dwSM1fwqWpWkeS3v86pgKt",
},
{
name: "test vector 2 chain m/0/2147483647H",
master: testVec2MasterHex,
path: []uint32{0, hkStart + 2147483647},
wantPub: "xpub6ASAVgeehLbnwdqV6UKMHVzgqAG8Gr6riv3Fxxpj8ksbH9ebxaEyBLZ85ySDhKiLDBrQSARLq1uNRts8RuJiHjaDMBU4Zn9h8LZNnBC5y4a",
wantPriv: "xprv9wSp6B7kry3Vj9m1zSnLvN3xH8RdsPP1Mh7fAaR7aRLcQMKTR2vidYEeEg2mUCTAwCd6vnxVrcjfy2kRgVsFawNzmjuHc2YmYRmagcEPdU9",
},
{
name: "test vector 2 chain m/0/2147483647H/1",
master: testVec2MasterHex,
path: []uint32{0, hkStart + 2147483647, 1},
wantPub: "xpub6DF8uhdarytz3FWdA8TvFSvvAh8dP3283MY7p2V4SeE2wyWmG5mg5EwVvmdMVCQcoNJxGoWaU9DCWh89LojfZ537wTfunKau47EL2dhHKon",
wantPriv: "xprv9zFnWC6h2cLgpmSA46vutJzBcfJ8yaJGg8cX1e5StJh45BBciYTRXSd25UEPVuesF9yog62tGAQtHjXajPPdbRCHuWS6T8XA2ECKADdw4Ef",
},
{
name: "test vector 2 chain m/0/2147483647H/1/2147483646H",
master: testVec2MasterHex,
path: []uint32{0, hkStart + 2147483647, 1, hkStart + 2147483646},
wantPub: "xpub6ERApfZwUNrhLCkDtcHTcxd75RbzS1ed54G1LkBUHQVHQKqhMkhgbmJbZRkrgZw4koxb5JaHWkY4ALHY2grBGRjaDMzQLcgJvLJuZZvRcEL",
wantPriv: "xprvA1RpRA33e1JQ7ifknakTFpgNXPmW2YvmhqLQYMmrj4xJXXWYpDPS3xz7iAxn8L39njGVyuoseXzU6rcxFLJ8HFsTjSyQbLYnMpCqE2VbFWc",
},
{
name: "test vector 2 chain m/0/2147483647H/1/2147483646H/2",
master: testVec2MasterHex,
path: []uint32{0, hkStart + 2147483647, 1, hkStart + 2147483646, 2},
wantPub: "xpub6FnCn6nSzZAw5Tw7cgR9bi15UV96gLZhjDstkXXxvCLsUXBGXPdSnLFbdpq8p9HmGsApME5hQTZ3emM2rnY5agb9rXpVGyy3bdW6EEgAtqt",
wantPriv: "xprvA2nrNbFZABcdryreWet9Ea4LvTJcGsqrMzxHx98MMrotbir7yrKCEXw7nadnHM8Dq38EGfSh6dqA9QWTyefMLEcBYJUuekgW4BYPJcr9E7j",
},
}
tests:
for i, test := range tests {
masterSeed, err := hex.DecodeString(test.master)
if err != nil {
t.Errorf("DecodeString #%d (%s): unexpected error: %v",
i, test.name, err)
continue
}
extKey, err := hdkeychain.NewMaster(masterSeed)
if err != nil {
t.Errorf("NewMaster #%d (%s): unexpected error when "+
"creating new master key: %v", i, test.name,
err)
continue
}
for _, childNum := range test.path {
var err error
extKey, err = extKey.Child(childNum)
if err != nil {
t.Errorf("err: %v", err)
continue tests
}
}
privStr := extKey.String()
if privStr != test.wantPriv {
t.Errorf("Serialize #%d (%s): mismatched serialized "+
"private extended key -- got: %s, want: %s", i,
test.name, privStr, test.wantPriv)
continue
}
pubKey, err := extKey.Neuter()
if err != nil {
t.Errorf("Neuter #%d (%s): unexpected error: %v ", i,
test.name, err)
continue
}
// Neutering a second time should have no effect.
pubKey, err = pubKey.Neuter()
if err != nil {
t.Errorf("Neuter #%d (%s): unexpected error: %v", i,
test.name, err)
return
}
pubStr := pubKey.String()
if pubStr != test.wantPub {
t.Errorf("Neuter #%d (%s): mismatched serialized "+
"public extended key -- got: %s, want: %s", i,
test.name, pubStr, test.wantPub)
continue
}
}
}
// TestPublicDerivation tests several vectors which derive public keys from
// other public keys works as intended.
func TestPublicDerivation(t *testing.T) {
// The public extended keys for test vectors in [BIP32].
testVec1MasterPubKey := "xpub661MyMwAqRbcFtXgS5sYJABqqG9YLmC4Q1Rdap9gSE8NqtwybGhePY2gZ29ESFjqJoCu1Rupje8YtGqsefD265TMg7usUDFdp6W1EGMcet8"
testVec2MasterPubKey := "xpub661MyMwAqRbcFW31YEwpkMuc5THy2PSt5bDMsktWQcFF8syAmRUapSCGu8ED9W6oDMSgv6Zz8idoc4a6mr8BDzTJY47LJhkJ8UB7WEGuduB"
var tests = []struct {
name string
master string
path []uint32
wantPub string
}{
// Test vector 1
{
name: "test vector 1 chain m",
master: testVec1MasterPubKey,
path: []uint32{},
wantPub: "xpub661MyMwAqRbcFtXgS5sYJABqqG9YLmC4Q1Rdap9gSE8NqtwybGhePY2gZ29ESFjqJoCu1Rupje8YtGqsefD265TMg7usUDFdp6W1EGMcet8",
},
{
name: "test vector 1 chain m/0",
master: testVec1MasterPubKey,
path: []uint32{0},
wantPub: "xpub68Gmy5EVb2BdFbj2LpWrk1M7obNuaPTpT5oh9QCCo5sRfqSHVYWex97WpDZzszdzHzxXDAzPLVSwybe4uPYkSk4G3gnrPqqkV9RyNzAcNJ1",
},
{
name: "test vector 1 chain m/0/1",
master: testVec1MasterPubKey,
path: []uint32{0, 1},
wantPub: "xpub6AvUGrnEpfvJBbfx7sQ89Q8hEMPM65UteqEX4yUbUiES2jHfjexmfJoxCGSwFMZiPBaKQT1RiKWrKfuDV4vpgVs4Xn8PpPTR2i79rwHd4Zr",
},
{
name: "test vector 1 chain m/0/1/2",
master: testVec1MasterPubKey,
path: []uint32{0, 1, 2},
wantPub: "xpub6BqyndF6rhZqmgktFCBcapkwubGxPqoAZtQaYewJHXVKZcLdnqBVC8N6f6FSHWUghjuTLeubWyQWfJdk2G3tGgvgj3qngo4vLTnnSjAZckv",
},
{
name: "test vector 1 chain m/0/1/2/2",
master: testVec1MasterPubKey,
path: []uint32{0, 1, 2, 2},
wantPub: "xpub6FHUhLbYYkgFQiFrDiXRfQFXBB2msCxKTsNyAExi6keFxQ8sHfwpogY3p3s1ePSpUqLNYks5T6a3JqpCGszt4kxbyq7tUoFP5c8KWyiDtPp",
},
{
name: "test vector 1 chain m/0/1/2/2/1000000000",
master: testVec1MasterPubKey,
path: []uint32{0, 1, 2, 2, 1000000000},
wantPub: "xpub6GX3zWVgSgPc5tgjE6ogT9nfwSADD3tdsxpzd7jJoJMqSY12Be6VQEFwDCp6wAQoZsH2iq5nNocHEaVDxBcobPrkZCjYW3QUmoDYzMFBDu9",
},
// Test vector 2
{
name: "test vector 2 chain m",
master: testVec2MasterPubKey,
path: []uint32{},
wantPub: "xpub661MyMwAqRbcFW31YEwpkMuc5THy2PSt5bDMsktWQcFF8syAmRUapSCGu8ED9W6oDMSgv6Zz8idoc4a6mr8BDzTJY47LJhkJ8UB7WEGuduB",
},
{
name: "test vector 2 chain m/0",
master: testVec2MasterPubKey,
path: []uint32{0},
wantPub: "xpub69H7F5d8KSRgmmdJg2KhpAK8SR3DjMwAdkxj3ZuxV27CprR9LgpeyGmXUbC6wb7ERfvrnKZjXoUmmDznezpbZb7ap6r1D3tgFxHmwMkQTPH",
},
{
name: "test vector 2 chain m/0/2147483647",
master: testVec2MasterPubKey,
path: []uint32{0, 2147483647},
wantPub: "xpub6ASAVgeWMg4pmutghzHG3BohahjwNwPmy2DgM6W9wGegtPrvNgjBwuZRD7hSDFhYfunq8vDgwG4ah1gVzZysgp3UsKz7VNjCnSUJJ5T4fdD",
},
{
name: "test vector 2 chain m/0/2147483647/1",
master: testVec2MasterPubKey,
path: []uint32{0, 2147483647, 1},
wantPub: "xpub6CrnV7NzJy4VdgP5niTpqWJiFXMAca6qBm5Hfsry77SQmN1HGYHnjsZSujoHzdxf7ZNK5UVrmDXFPiEW2ecwHGWMFGUxPC9ARipss9rXd4b",
},
{
name: "test vector 2 chain m/0/2147483647/1/2147483646",
master: testVec2MasterPubKey,
path: []uint32{0, 2147483647, 1, 2147483646},
wantPub: "xpub6FL2423qFaWzHCvBndkN9cbkn5cysiUeFq4eb9t9kE88jcmY63tNuLNRzpHPdAM4dUpLhZ7aUm2cJ5zF7KYonf4jAPfRqTMTRBNkQL3Tfta",
},
{
name: "test vector 2 chain m/0/2147483647/1/2147483646/2",
master: testVec2MasterPubKey,
path: []uint32{0, 2147483647, 1, 2147483646, 2},
wantPub: "xpub6H7WkJf547AiSwAbX6xsm8Bmq9M9P1Gjequ5SipsjipWmtXSyp4C3uwzewedGEgAMsDy4jEvNTWtxLyqqHY9C12gaBmgUdk2CGmwachwnWK",
},
}
tests:
for i, test := range tests {
extKey, err := hdkeychain.NewKeyFromString(test.master)
if err != nil {
t.Errorf("NewKeyFromString #%d (%s): unexpected error "+
"creating extended key: %v", i, test.name,
err)
continue
}
for _, childNum := range test.path {
var err error
extKey, err = extKey.Child(childNum)
if err != nil {
t.Errorf("err: %v", err)
continue tests
}
}
pubStr := extKey.String()
if pubStr != test.wantPub {
t.Errorf("Child #%d (%s): mismatched serialized "+
"public extended key -- got: %s, want: %s", i,
test.name, pubStr, test.wantPub)
continue
}
}
}
// TestGenenerateSeed ensures the GenerateSeed function works as intended.
func TestGenenerateSeed(t *testing.T) {
wantErr := errors.New("seed length must be between 128 and 512 bits")
var tests = []struct {
name string
length uint8
err error
}{
// Test various valid lengths.
{name: "16 bytes", length: 16},
{name: "17 bytes", length: 17},
{name: "20 bytes", length: 20},
{name: "32 bytes", length: 32},
{name: "64 bytes", length: 64},
// Test invalid lengths.
{name: "15 bytes", length: 15, err: wantErr},
{name: "65 bytes", length: 65, err: wantErr},
}
for i, test := range tests {
seed, err := hdkeychain.GenerateSeed(test.length)
if !reflect.DeepEqual(err, test.err) {
t.Errorf("GenerateSeed #%d (%s): unexpected error -- "+
"want %v, got %v", i, test.name, test.err, err)
continue
}
if test.err == nil && len(seed) != int(test.length) {
t.Errorf("GenerateSeed #%d (%s): length mismatch -- "+
"got %d, want %d", i, test.name, len(seed),
test.length)
continue
}
}
}
// TestExtendedKeyAPI ensures the API on the ExtendedKey type works as intended.
func TestExtendedKeyAPI(t *testing.T) {
var tests = []struct {
name string
extKey string
isPrivate bool
parentFP uint32
privKey string
privKeyErr error
pubKey string
address string
}{
{
name: "test vector 1 master node private",
extKey: "xprv9s21ZrQH143K3QTDL4LXw2F7HEK3wJUD2nW2nRk4stbPy6cq3jPPqjiChkVvvNKmPGJxWUtg6LnF5kejMRNNU3TGtRBeJgk33yuGBxrMPHi",
isPrivate: true,
parentFP: 0,
privKey: "e8f32e723decf4051aefac8e2c93c9c5b214313817cdb01a1494b917c8436b35",
pubKey: "0339a36013301597daef41fbe593a02cc513d0b55527ec2df1050e2e8ff49c85c2",
address: "15mKKb2eos1hWa6tisdPwwDC1a5J1y9nma",
},
{
name: "test vector 1 chain m/0H/1/2H public",
extKey: "xpub6D4BDPcP2GT577Vvch3R8wDkScZWzQzMMUm3PWbmWvVJrZwQY4VUNgqFJPMM3No2dFDFGTsxxpG5uJh7n7epu4trkrX7x7DogT5Uv6fcLW5",
isPrivate: false,
parentFP: 3203769081,
privKeyErr: hdkeychain.ErrNotPrivExtKey,
pubKey: "0357bfe1e341d01c69fe5654309956cbea516822fba8a601743a012a7896ee8dc2",
address: "1NjxqbA9aZWnh17q1UW3rB4EPu79wDXj7x",
},
}
for i, test := range tests {
key, err := hdkeychain.NewKeyFromString(test.extKey)
if err != nil {
t.Errorf("NewKeyFromString #%d (%s): unexpected "+
"error: %v", i, test.name, err)
continue
}
if key.IsPrivate() != test.isPrivate {
t.Errorf("IsPrivate #%d (%s): mismatched key type -- "+
"want private %v, got private %v", i, test.name,
test.isPrivate, key.IsPrivate())
continue
}
parentFP := key.ParentFingerprint()
if parentFP != test.parentFP {
t.Errorf("ParentFingerprint #%d (%s): mismatched "+
"parent fingerprint -- want %d, got %d", i,
test.name, test.parentFP, parentFP)
continue
}
serializedKey := key.String()
if serializedKey != test.extKey {
t.Errorf("String #%d (%s): mismatched serialized key "+
"-- want %s, got %s", i, test.name, test.extKey,
serializedKey)
continue
}
privKey, err := key.ECPrivKey()
if !reflect.DeepEqual(err, test.privKeyErr) {
t.Errorf("ECPrivKey #%d (%s): mismatched error: want "+
"%v, got %v", i, test.name, test.privKeyErr, err)
continue
}
if test.privKeyErr == nil {
privKeyStr := hex.EncodeToString(privKey.Serialize())
if privKeyStr != test.privKey {
t.Errorf("ECPrivKey #%d (%s): mismatched "+
"private key -- want %s, got %s", i,
test.name, test.privKey, privKeyStr)
continue
}
}
pubKey, err := key.ECPubKey()
if err != nil {
t.Errorf("ECPubKey #%d (%s): unexpected error: %v", i,
test.name, err)
continue
}
pubKeyStr := hex.EncodeToString(pubKey.SerializeCompressed())
if pubKeyStr != test.pubKey {
t.Errorf("ECPubKey #%d (%s): mismatched public key -- "+
"want %s, got %s", i, test.name, test.pubKey,
pubKeyStr)
continue
}
addr, err := key.Address(&btcnet.MainNetParams)
if err != nil {
t.Errorf("Address #%d (%s): unexpected error: %v", i,
test.name, err)
continue
}
if addr.EncodeAddress() != test.address {
t.Errorf("Address #%d (%s): mismatched address -- want "+
"%s, got %s", i, test.name, test.address,
addr.EncodeAddress())
continue
}
}
}
// TestNet ensures the network related APIs work as intended.
func TestNet(t *testing.T) {
var tests = []struct {
name string
key string
origNet *btcnet.Params
newNet *btcnet.Params
newPriv string
newPub string
isPrivate bool
}{
// Private extended keys.
{
name: "mainnet -> simnet",
key: "xprv9s21ZrQH143K3QTDL4LXw2F7HEK3wJUD2nW2nRk4stbPy6cq3jPPqjiChkVvvNKmPGJxWUtg6LnF5kejMRNNU3TGtRBeJgk33yuGBxrMPHi",
origNet: &btcnet.MainNetParams,
newNet: &btcnet.SimNetParams,
newPriv: "sprv8Erh3X3hFeKunvVdAGQQtambRPapECWiTDtvsTGdyrhzhbYgnSZajRRWbihzvq4AM4ivm6uso31VfKaukwJJUs3GYihXP8ebhMb3F2AHu3P",
newPub: "spub4Tr3T2ab61tD1Qa6GHwRFiiKyRRJdfEZpSpXfqgFYCEyaPsqKysqHDjzSzMJSiUEGbcsG3w2SLMoTqn44B8x6u3MLRRkYfACTUBnHK79THk",
isPrivate: true,
},
{
name: "simnet -> mainnet",
key: "sprv8Erh3X3hFeKunvVdAGQQtambRPapECWiTDtvsTGdyrhzhbYgnSZajRRWbihzvq4AM4ivm6uso31VfKaukwJJUs3GYihXP8ebhMb3F2AHu3P",
origNet: &btcnet.SimNetParams,
newNet: &btcnet.MainNetParams,
newPriv: "xprv9s21ZrQH143K3QTDL4LXw2F7HEK3wJUD2nW2nRk4stbPy6cq3jPPqjiChkVvvNKmPGJxWUtg6LnF5kejMRNNU3TGtRBeJgk33yuGBxrMPHi",
newPub: "xpub661MyMwAqRbcFtXgS5sYJABqqG9YLmC4Q1Rdap9gSE8NqtwybGhePY2gZ29ESFjqJoCu1Rupje8YtGqsefD265TMg7usUDFdp6W1EGMcet8",
isPrivate: true,
},
{
name: "mainnet -> regtest",
key: "xprv9s21ZrQH143K3QTDL4LXw2F7HEK3wJUD2nW2nRk4stbPy6cq3jPPqjiChkVvvNKmPGJxWUtg6LnF5kejMRNNU3TGtRBeJgk33yuGBxrMPHi",
origNet: &btcnet.MainNetParams,
newNet: &btcnet.RegressionNetParams,
newPriv: "tprv8ZgxMBicQKsPeDgjzdC36fs6bMjGApWDNLR9erAXMs5skhMv36j9MV5ecvfavji5khqjWaWSFhN3YcCUUdiKH6isR4Pwy3U5y5egddBr16m",
newPub: "tpubD6NzVbkrYhZ4XgiXtGrdW5XDAPFCL9h7we1vwNCpn8tGbBcgfVYjXyhWo4E1xkh56hjod1RhGjxbaTLV3X4FyWuejifB9jusQ46QzG87VKp",
isPrivate: true,
},
{
name: "regtest -> mainnet",
key: "tprv8ZgxMBicQKsPeDgjzdC36fs6bMjGApWDNLR9erAXMs5skhMv36j9MV5ecvfavji5khqjWaWSFhN3YcCUUdiKH6isR4Pwy3U5y5egddBr16m",
origNet: &btcnet.RegressionNetParams,
newNet: &btcnet.MainNetParams,
newPriv: "xprv9s21ZrQH143K3QTDL4LXw2F7HEK3wJUD2nW2nRk4stbPy6cq3jPPqjiChkVvvNKmPGJxWUtg6LnF5kejMRNNU3TGtRBeJgk33yuGBxrMPHi",
newPub: "xpub661MyMwAqRbcFtXgS5sYJABqqG9YLmC4Q1Rdap9gSE8NqtwybGhePY2gZ29ESFjqJoCu1Rupje8YtGqsefD265TMg7usUDFdp6W1EGMcet8",
isPrivate: true,
},
// Public extended keys.
{
name: "mainnet -> simnet",
key: "xpub661MyMwAqRbcFtXgS5sYJABqqG9YLmC4Q1Rdap9gSE8NqtwybGhePY2gZ29ESFjqJoCu1Rupje8YtGqsefD265TMg7usUDFdp6W1EGMcet8",
origNet: &btcnet.MainNetParams,
newNet: &btcnet.SimNetParams,
newPub: "spub4Tr3T2ab61tD1Qa6GHwRFiiKyRRJdfEZpSpXfqgFYCEyaPsqKysqHDjzSzMJSiUEGbcsG3w2SLMoTqn44B8x6u3MLRRkYfACTUBnHK79THk",
isPrivate: false,
},
{
name: "simnet -> mainnet",
key: "spub4Tr3T2ab61tD1Qa6GHwRFiiKyRRJdfEZpSpXfqgFYCEyaPsqKysqHDjzSzMJSiUEGbcsG3w2SLMoTqn44B8x6u3MLRRkYfACTUBnHK79THk",
origNet: &btcnet.SimNetParams,
newNet: &btcnet.MainNetParams,
newPub: "xpub661MyMwAqRbcFtXgS5sYJABqqG9YLmC4Q1Rdap9gSE8NqtwybGhePY2gZ29ESFjqJoCu1Rupje8YtGqsefD265TMg7usUDFdp6W1EGMcet8",
isPrivate: false,
},
{
name: "mainnet -> regtest",
key: "xpub661MyMwAqRbcFtXgS5sYJABqqG9YLmC4Q1Rdap9gSE8NqtwybGhePY2gZ29ESFjqJoCu1Rupje8YtGqsefD265TMg7usUDFdp6W1EGMcet8",
origNet: &btcnet.MainNetParams,
newNet: &btcnet.RegressionNetParams,
newPub: "tpubD6NzVbkrYhZ4XgiXtGrdW5XDAPFCL9h7we1vwNCpn8tGbBcgfVYjXyhWo4E1xkh56hjod1RhGjxbaTLV3X4FyWuejifB9jusQ46QzG87VKp",
isPrivate: false,
},
{
name: "regtest -> mainnet",
key: "tpubD6NzVbkrYhZ4XgiXtGrdW5XDAPFCL9h7we1vwNCpn8tGbBcgfVYjXyhWo4E1xkh56hjod1RhGjxbaTLV3X4FyWuejifB9jusQ46QzG87VKp",
origNet: &btcnet.RegressionNetParams,
newNet: &btcnet.MainNetParams,
newPub: "xpub661MyMwAqRbcFtXgS5sYJABqqG9YLmC4Q1Rdap9gSE8NqtwybGhePY2gZ29ESFjqJoCu1Rupje8YtGqsefD265TMg7usUDFdp6W1EGMcet8",
isPrivate: false,
},
}
for i, test := range tests {
extKey, err := hdkeychain.NewKeyFromString(test.key)
if err != nil {
t.Errorf("NewKeyFromString #%d (%s): unexpected error "+
"creating extended key: %v", i, test.name,
err)
continue
}
if !extKey.IsForNet(test.origNet) {
t.Errorf("IsForNet #%d (%s): key is not for expected "+
"network %v", i, test.name, test.origNet.Name)
continue
}
extKey.SetNet(test.newNet)
if !extKey.IsForNet(test.newNet) {
t.Errorf("SetNet/IsForNet #%d (%s): key is not for "+
"expected network %v", i, test.name,
test.newNet.Name)
continue
}
if test.isPrivate {
privStr := extKey.String()
if privStr != test.newPriv {
t.Errorf("Serialize #%d (%s): mismatched serialized "+
"private extended key -- got: %s, want: %s", i,
test.name, privStr, test.newPriv)
continue
}
extKey, err = extKey.Neuter()
if err != nil {
t.Errorf("Neuter #%d (%s): unexpected error: %v ", i,
test.name, err)
continue
}
}
pubStr := extKey.String()
if pubStr != test.newPub {
t.Errorf("Neuter #%d (%s): mismatched serialized "+
"public extended key -- got: %s, want: %s", i,
test.name, pubStr, test.newPub)
continue
}
}
}
// TestErrors performs some negative tests for various invalid cases to ensure
// the errors are handled properly.
func TestErrors(t *testing.T) {
// Should get an error when seed has too few bytes.
_, err := hdkeychain.NewMaster(bytes.Repeat([]byte{0x00}, 15))
if err != hdkeychain.ErrInvalidSeedLen {
t.Errorf("NewMaster: mismatched error -- got: %v, want: %v",
err, hdkeychain.ErrInvalidSeedLen)
}
// Should get an error when seed has too many bytes.
_, err = hdkeychain.NewMaster(bytes.Repeat([]byte{0x00}, 65))
if err != hdkeychain.ErrInvalidSeedLen {
t.Errorf("NewMaster: mismatched error -- got: %v, want: %v",
err, hdkeychain.ErrInvalidSeedLen)
}
// Generate a new key and neuter it to a public extended key.
seed, err := hdkeychain.GenerateSeed(hdkeychain.RecommendedSeedLen)
if err != nil {
t.Errorf("GenerateSeed: unexpected error: %v", err)
return
}
extKey, err := hdkeychain.NewMaster(seed)
if err != nil {
t.Errorf("NewMaster: unexpected error: %v", err)
return
}
pubKey, err := extKey.Neuter()
if err != nil {
t.Errorf("Neuter: unexpected error: %v", err)
return
}
// Deriving a hardened child extended key should fail from a public key.
_, err = pubKey.Child(hdkeychain.HardenedKeyStart)
if err != hdkeychain.ErrDeriveHardFromPublic {
t.Errorf("Child: mismatched error -- got: %v, want: %v",
err, hdkeychain.ErrDeriveHardFromPublic)
}
// NewKeyFromString failure tests.
tests := []struct {
name string
key string
err error
neuter bool
neuterErr error
}{
{
name: "invalid key length",
key: "xpub1234",
err: hdkeychain.ErrInvalidKeyLen,
},
{
name: "bad checksum",
key: "xpub661MyMwAqRbcFtXgS5sYJABqqG9YLmC4Q1Rdap9gSE8NqtwybGhePY2gZ29ESFjqJoCu1Rupje8YtGqsefD265TMg7usUDFdp6W1EBygr15",
err: hdkeychain.ErrBadChecksum,
},
{
name: "pubkey not on curve",
key: "xpub661MyMwAqRbcFtXgS5sYJABqqG9YLmC4Q1Rdap9gSE8NqtwybGhePY2gZ1hr9Rwbk95YadvBkQXxzHBSngB8ndpW6QH7zhhsXZ2jHyZqPjk",
err: errors.New("pubkey isn't on secp265k1 curve"),
},
{
name: "unsupported version",
key: "xbad4LfUL9eKmA66w2GJdVMqhvDmYGJpTGjWRAtjHqoUY17sGaymoMV9Cm3ocn9Ud6Hh2vLFVC7KSKCRVVrqc6dsEdsTjRV1WUmkK85YEUujAPX",
err: nil,
neuter: true,
neuterErr: btcnet.ErrUnknownHDKeyID,
},
}
for i, test := range tests {
extKey, err := hdkeychain.NewKeyFromString(test.key)
if !reflect.DeepEqual(err, test.err) {
t.Errorf("NewKeyFromString #%d (%s): mismatched error "+
"-- got: %v, want: %v", i, test.name, err,
test.err)
continue
}
if test.neuter {
_, err := extKey.Neuter()
if !reflect.DeepEqual(err, test.neuterErr) {
t.Errorf("Neuter #%d (%s): mismatched error "+
"-- got: %v, want: %v", i, test.name,
err, test.neuterErr)
continue
}
}
}
}

18
hdkeychain/test_coverage.txt Normal file
View file

@ -0,0 +1,18 @@
github.com/conformal/btcutil/hdkeychain/extendedkey.go ExtendedKey.String 100.00% (16/16)
github.com/conformal/btcutil/hdkeychain/extendedkey.go ExtendedKey.pubKeyBytes 100.00% (7/7)
github.com/conformal/btcutil/hdkeychain/extendedkey.go ExtendedKey.Neuter 100.00% (6/6)
github.com/conformal/btcutil/hdkeychain/extendedkey.go ExtendedKey.ECPrivKey 100.00% (4/4)
github.com/conformal/btcutil/hdkeychain/extendedkey.go ExtendedKey.SetNet 100.00% (3/3)
github.com/conformal/btcutil/hdkeychain/extendedkey.go ExtendedKey.Address 100.00% (2/2)
github.com/conformal/btcutil/hdkeychain/extendedkey.go newExtendedKey 100.00% (1/1)
github.com/conformal/btcutil/hdkeychain/extendedkey.go ExtendedKey.IsPrivate 100.00% (1/1)
github.com/conformal/btcutil/hdkeychain/extendedkey.go ExtendedKey.ParentFingerprint 100.00% (1/1)
github.com/conformal/btcutil/hdkeychain/extendedkey.go ExtendedKey.ECPubKey 100.00% (1/1)
github.com/conformal/btcutil/hdkeychain/extendedkey.go ExtendedKey.IsForNet 100.00% (1/1)
github.com/conformal/btcutil/hdkeychain/extendedkey.go NewKeyFromString 95.83% (23/24)
github.com/conformal/btcutil/hdkeychain/extendedkey.go ExtendedKey.Child 91.67% (33/36)
github.com/conformal/btcutil/hdkeychain/extendedkey.go NewMaster 91.67% (11/12)
github.com/conformal/btcutil/hdkeychain/extendedkey.go GenerateSeed 85.71% (6/7)
github.com/conformal/btcutil/hdkeychain ----------------------------- 95.08% (116/122)