示例#1
0
// indexScriptPubKey indexes all data pushes greater than 8 bytes within the
// passed SPK. Our "address" index is actually a hash160 index, where in the
// ideal case the data push is either the hash160 of a publicKey (P2PKH) or
// a Script (P2SH).
func indexScriptPubKey(addrIndex database.BlockAddrIndex, scriptPubKey []byte,
	locInBlock *wire.TxLoc) error {
	dataPushes, err := txscript.PushedData(scriptPubKey)
	if err != nil {
		adxrLog.Tracef("Couldn't get pushes: %v", err)
		return err
	}

	for _, data := range dataPushes {
		// Only index pushes greater than 8 bytes.
		if len(data) < 8 {
			continue
		}

		var indexKey [ripemd160.Size]byte
		// A perfect little hash160.
		if len(data) <= 20 {
			copy(indexKey[:], data)
			// Otherwise, could be a payToPubKey or an OP_RETURN, so we'll
			// make a hash160 out of it.
		} else {
			copy(indexKey[:], btcutil.Hash160(data))
		}

		addrIndex[indexKey] = append(addrIndex[indexKey], locInBlock)
	}
	return nil
}
// TestFilterInsertKey ensures inserting public keys and addresses works as
// expected.
func TestFilterInsertKey(t *testing.T) {
	secret := "5Kg1gnAjaLfKiwhhPpGS3QfRg2m6awQvaj98JCZBZQ5SuS2F15C"

	wif, err := btcutil.DecodeWIF(secret)
	if err != nil {
		t.Errorf("TestFilterInsertKey DecodeWIF failed: %v", err)
		return
	}

	f := bloom.NewFilter(2, 0, 0.001, wire.BloomUpdateAll)
	f.Add(wif.SerializePubKey())
	f.Add(btcutil.Hash160(wif.SerializePubKey()))

	want, err := hex.DecodeString("038fc16b080000000000000001")
	if err != nil {
		t.Errorf("TestFilterInsertWithTweak DecodeString failed: %v\n", err)
		return
	}
	got := bytes.NewBuffer(nil)
	err = f.MsgFilterLoad().BtcEncode(got, wire.ProtocolVersion)
	if err != nil {
		t.Errorf("TestFilterInsertWithTweak BtcDecode failed: %v\n", err)
		return
	}

	if !bytes.Equal(got.Bytes(), want) {
		t.Errorf("TestFilterInsertWithTweak failure: got %v want %v\n",
			got.Bytes(), want)
		return
	}
}
示例#3
0
func TestAddrIndexKeySerialization(t *testing.T) {
	var hash160Bytes [ripemd160.Size]byte
	var packedIndex [12]byte

	fakeHash160 := btcutil.Hash160([]byte("testing"))
	copy(fakeHash160, hash160Bytes[:])

	fakeIndex := txAddrIndex{
		hash160:   hash160Bytes,
		blkHeight: 1,
		txoffset:  5,
		txlen:     360,
	}

	serializedKey := addrIndexToKey(&fakeIndex)
	copy(packedIndex[:], serializedKey[23:35])
	unpackedIndex := unpackTxIndex(packedIndex)

	if unpackedIndex.blkHeight != fakeIndex.blkHeight {
		t.Errorf("Incorrect block height. Unpack addr index key"+
			"serialization failed. Expected %d, received %d",
			1, unpackedIndex.blkHeight)
	}

	if unpackedIndex.txoffset != fakeIndex.txoffset {
		t.Errorf("Incorrect tx offset. Unpack addr index key"+
			"serialization failed. Expected %d, received %d",
			5, unpackedIndex.txoffset)
	}

	if unpackedIndex.txlen != fakeIndex.txlen {
		t.Errorf("Incorrect tx len. Unpack addr index key"+
			"serialization failed. Expected %d, received %d",
			360, unpackedIndex.txlen)
	}
}
示例#4
0
func TestSignTxOutput(t *testing.T) {
	t.Parallel()

	// make key
	// make script based on key.
	// sign with magic pixie dust.
	hashTypes := []txscript.SigHashType{
		txscript.SigHashOld, // no longer used but should act like all
		txscript.SigHashAll,
		txscript.SigHashNone,
		txscript.SigHashSingle,
		txscript.SigHashAll | txscript.SigHashAnyOneCanPay,
		txscript.SigHashNone | txscript.SigHashAnyOneCanPay,
		txscript.SigHashSingle | txscript.SigHashAnyOneCanPay,
	}
	tx := &wire.MsgTx{
		Version: 1,
		TxIn: []*wire.TxIn{
			&wire.TxIn{
				PreviousOutPoint: wire.OutPoint{
					Hash:  wire.ShaHash{},
					Index: 0,
				},
				Sequence: 4294967295,
			},
			&wire.TxIn{
				PreviousOutPoint: wire.OutPoint{
					Hash:  wire.ShaHash{},
					Index: 1,
				},
				Sequence: 4294967295,
			},
			&wire.TxIn{
				PreviousOutPoint: wire.OutPoint{
					Hash:  wire.ShaHash{},
					Index: 2,
				},
				Sequence: 4294967295,
			},
		},
		TxOut: []*wire.TxOut{
			&wire.TxOut{
				Value: 1,
			},
			&wire.TxOut{
				Value: 2,
			},
			&wire.TxOut{
				Value: 3,
			},
		},
		LockTime: 0,
	}

	// Pay to Pubkey Hash (uncompressed)
	for _, hashType := range hashTypes {
		for i := range tx.TxIn {
			msg := fmt.Sprintf("%d:%d", hashType, i)
			key, err := btcec.NewPrivateKey(btcec.S256())
			if err != nil {
				t.Errorf("failed to make privKey for %s: %v",
					msg, err)
				break
			}

			pk := (*btcec.PublicKey)(&key.PublicKey).
				SerializeUncompressed()
			address, err := btcutil.NewAddressPubKeyHash(
				btcutil.Hash160(pk), &chaincfg.TestNet3Params)
			if err != nil {
				t.Errorf("failed to make address for %s: %v",
					msg, err)
				break
			}

			pkScript, err := txscript.PayToAddrScript(address)
			if err != nil {
				t.Errorf("failed to make pkscript "+
					"for %s: %v", msg, err)
			}

			if err := signAndCheck(msg, tx, i, pkScript, hashType,
				mkGetKey(map[string]addressToKey{
					address.EncodeAddress(): {key, false},
				}), mkGetScript(nil), nil); err != nil {
				t.Error(err)
				break
			}
		}
	}

	// Pay to Pubkey Hash (uncompressed) (merging with correct)
	for _, hashType := range hashTypes {
		for i := range tx.TxIn {
			msg := fmt.Sprintf("%d:%d", hashType, i)
			key, err := btcec.NewPrivateKey(btcec.S256())
			if err != nil {
				t.Errorf("failed to make privKey for %s: %v",
					msg, err)
				break
			}

			pk := (*btcec.PublicKey)(&key.PublicKey).
				SerializeUncompressed()
			address, err := btcutil.NewAddressPubKeyHash(
				btcutil.Hash160(pk), &chaincfg.TestNet3Params)
			if err != nil {
				t.Errorf("failed to make address for %s: %v",
					msg, err)
				break
			}

			pkScript, err := txscript.PayToAddrScript(address)
			if err != nil {
				t.Errorf("failed to make pkscript "+
					"for %s: %v", msg, err)
			}

			sigScript, err := txscript.SignTxOutput(
				&chaincfg.TestNet3Params, tx, i, pkScript,
				hashType, mkGetKey(map[string]addressToKey{
					address.EncodeAddress(): {key, false},
				}), mkGetScript(nil), nil)
			if err != nil {
				t.Errorf("failed to sign output %s: %v", msg,
					err)
				break
			}

			// by the above loop, this should be valid, now sign
			// again and merge.
			sigScript, err = txscript.SignTxOutput(
				&chaincfg.TestNet3Params, tx, i, pkScript,
				hashType, mkGetKey(map[string]addressToKey{
					address.EncodeAddress(): {key, false},
				}), mkGetScript(nil), sigScript)
			if err != nil {
				t.Errorf("failed to sign output %s a "+
					"second time: %v", msg, err)
				break
			}

			err = checkScripts(msg, tx, i, sigScript, pkScript)
			if err != nil {
				t.Errorf("twice signed script invalid for "+
					"%s: %v", msg, err)
				break
			}
		}
	}

	// Pay to Pubkey Hash (compressed)
	for _, hashType := range hashTypes {
		for i := range tx.TxIn {
			msg := fmt.Sprintf("%d:%d", hashType, i)

			key, err := btcec.NewPrivateKey(btcec.S256())
			if err != nil {
				t.Errorf("failed to make privKey for %s: %v",
					msg, err)
				break
			}

			pk := (*btcec.PublicKey)(&key.PublicKey).
				SerializeCompressed()
			address, err := btcutil.NewAddressPubKeyHash(
				btcutil.Hash160(pk), &chaincfg.TestNet3Params)
			if err != nil {
				t.Errorf("failed to make address for %s: %v",
					msg, err)
				break
			}

			pkScript, err := txscript.PayToAddrScript(address)
			if err != nil {
				t.Errorf("failed to make pkscript "+
					"for %s: %v", msg, err)
			}

			if err := signAndCheck(msg, tx, i, pkScript, hashType,
				mkGetKey(map[string]addressToKey{
					address.EncodeAddress(): {key, true},
				}), mkGetScript(nil), nil); err != nil {
				t.Error(err)
				break
			}
		}
	}

	// Pay to Pubkey Hash (compressed) with duplicate merge
	for _, hashType := range hashTypes {
		for i := range tx.TxIn {
			msg := fmt.Sprintf("%d:%d", hashType, i)

			key, err := btcec.NewPrivateKey(btcec.S256())
			if err != nil {
				t.Errorf("failed to make privKey for %s: %v",
					msg, err)
				break
			}

			pk := (*btcec.PublicKey)(&key.PublicKey).
				SerializeCompressed()
			address, err := btcutil.NewAddressPubKeyHash(
				btcutil.Hash160(pk), &chaincfg.TestNet3Params)
			if err != nil {
				t.Errorf("failed to make address for %s: %v",
					msg, err)
				break
			}

			pkScript, err := txscript.PayToAddrScript(address)
			if err != nil {
				t.Errorf("failed to make pkscript "+
					"for %s: %v", msg, err)
			}

			sigScript, err := txscript.SignTxOutput(
				&chaincfg.TestNet3Params, tx, i, pkScript,
				hashType, mkGetKey(map[string]addressToKey{
					address.EncodeAddress(): {key, true},
				}), mkGetScript(nil), nil)
			if err != nil {
				t.Errorf("failed to sign output %s: %v", msg,
					err)
				break
			}

			// by the above loop, this should be valid, now sign
			// again and merge.
			sigScript, err = txscript.SignTxOutput(
				&chaincfg.TestNet3Params, tx, i, pkScript,
				hashType, mkGetKey(map[string]addressToKey{
					address.EncodeAddress(): {key, true},
				}), mkGetScript(nil), sigScript)
			if err != nil {
				t.Errorf("failed to sign output %s a "+
					"second time: %v", msg, err)
				break
			}

			err = checkScripts(msg, tx, i, sigScript, pkScript)
			if err != nil {
				t.Errorf("twice signed script invalid for "+
					"%s: %v", msg, err)
				break
			}
		}
	}

	// Pay to PubKey (uncompressed)
	for _, hashType := range hashTypes {
		for i := range tx.TxIn {
			msg := fmt.Sprintf("%d:%d", hashType, i)

			key, err := btcec.NewPrivateKey(btcec.S256())
			if err != nil {
				t.Errorf("failed to make privKey for %s: %v",
					msg, err)
				break
			}

			pk := (*btcec.PublicKey)(&key.PublicKey).
				SerializeUncompressed()
			address, err := btcutil.NewAddressPubKey(pk,
				&chaincfg.TestNet3Params)
			if err != nil {
				t.Errorf("failed to make address for %s: %v",
					msg, err)
				break
			}

			pkScript, err := txscript.PayToAddrScript(address)
			if err != nil {
				t.Errorf("failed to make pkscript "+
					"for %s: %v", msg, err)
			}

			if err := signAndCheck(msg, tx, i, pkScript, hashType,
				mkGetKey(map[string]addressToKey{
					address.EncodeAddress(): {key, false},
				}), mkGetScript(nil), nil); err != nil {
				t.Error(err)
				break
			}
		}
	}

	// Pay to PubKey (uncompressed)
	for _, hashType := range hashTypes {
		for i := range tx.TxIn {
			msg := fmt.Sprintf("%d:%d", hashType, i)

			key, err := btcec.NewPrivateKey(btcec.S256())
			if err != nil {
				t.Errorf("failed to make privKey for %s: %v",
					msg, err)
				break
			}

			pk := (*btcec.PublicKey)(&key.PublicKey).
				SerializeUncompressed()
			address, err := btcutil.NewAddressPubKey(pk,
				&chaincfg.TestNet3Params)
			if err != nil {
				t.Errorf("failed to make address for %s: %v",
					msg, err)
				break
			}

			pkScript, err := txscript.PayToAddrScript(address)
			if err != nil {
				t.Errorf("failed to make pkscript "+
					"for %s: %v", msg, err)
			}

			sigScript, err := txscript.SignTxOutput(
				&chaincfg.TestNet3Params, tx, i, pkScript,
				hashType, mkGetKey(map[string]addressToKey{
					address.EncodeAddress(): {key, false},
				}), mkGetScript(nil), nil)
			if err != nil {
				t.Errorf("failed to sign output %s: %v", msg,
					err)
				break
			}

			// by the above loop, this should be valid, now sign
			// again and merge.
			sigScript, err = txscript.SignTxOutput(
				&chaincfg.TestNet3Params, tx, i, pkScript,
				hashType, mkGetKey(map[string]addressToKey{
					address.EncodeAddress(): {key, false},
				}), mkGetScript(nil), sigScript)
			if err != nil {
				t.Errorf("failed to sign output %s a "+
					"second time: %v", msg, err)
				break
			}

			err = checkScripts(msg, tx, i, sigScript, pkScript)
			if err != nil {
				t.Errorf("twice signed script invalid for "+
					"%s: %v", msg, err)
				break
			}
		}
	}

	// Pay to PubKey (compressed)
	for _, hashType := range hashTypes {
		for i := range tx.TxIn {
			msg := fmt.Sprintf("%d:%d", hashType, i)

			key, err := btcec.NewPrivateKey(btcec.S256())
			if err != nil {
				t.Errorf("failed to make privKey for %s: %v",
					msg, err)
				break
			}

			pk := (*btcec.PublicKey)(&key.PublicKey).
				SerializeCompressed()
			address, err := btcutil.NewAddressPubKey(pk,
				&chaincfg.TestNet3Params)
			if err != nil {
				t.Errorf("failed to make address for %s: %v",
					msg, err)
				break
			}

			pkScript, err := txscript.PayToAddrScript(address)
			if err != nil {
				t.Errorf("failed to make pkscript "+
					"for %s: %v", msg, err)
			}

			if err := signAndCheck(msg, tx, i, pkScript, hashType,
				mkGetKey(map[string]addressToKey{
					address.EncodeAddress(): {key, true},
				}), mkGetScript(nil), nil); err != nil {
				t.Error(err)
				break
			}
		}
	}

	// Pay to PubKey (compressed) with duplicate merge
	for _, hashType := range hashTypes {
		for i := range tx.TxIn {
			msg := fmt.Sprintf("%d:%d", hashType, i)

			key, err := btcec.NewPrivateKey(btcec.S256())
			if err != nil {
				t.Errorf("failed to make privKey for %s: %v",
					msg, err)
				break
			}

			pk := (*btcec.PublicKey)(&key.PublicKey).
				SerializeCompressed()
			address, err := btcutil.NewAddressPubKey(pk,
				&chaincfg.TestNet3Params)
			if err != nil {
				t.Errorf("failed to make address for %s: %v",
					msg, err)
				break
			}

			pkScript, err := txscript.PayToAddrScript(address)
			if err != nil {
				t.Errorf("failed to make pkscript "+
					"for %s: %v", msg, err)
			}

			sigScript, err := txscript.SignTxOutput(
				&chaincfg.TestNet3Params, tx, i, pkScript,
				hashType, mkGetKey(map[string]addressToKey{
					address.EncodeAddress(): {key, true},
				}), mkGetScript(nil), nil)
			if err != nil {
				t.Errorf("failed to sign output %s: %v", msg,
					err)
				break
			}

			// by the above loop, this should be valid, now sign
			// again and merge.
			sigScript, err = txscript.SignTxOutput(
				&chaincfg.TestNet3Params, tx, i, pkScript,
				hashType, mkGetKey(map[string]addressToKey{
					address.EncodeAddress(): {key, true},
				}), mkGetScript(nil), sigScript)
			if err != nil {
				t.Errorf("failed to sign output %s a "+
					"second time: %v", msg, err)
				break
			}

			err = checkScripts(msg, tx, i, sigScript, pkScript)
			if err != nil {
				t.Errorf("twice signed script invalid for "+
					"%s: %v", msg, err)
				break
			}
		}
	}

	// As before, but with p2sh now.
	// Pay to Pubkey Hash (uncompressed)
	for _, hashType := range hashTypes {
		for i := range tx.TxIn {
			msg := fmt.Sprintf("%d:%d", hashType, i)
			key, err := btcec.NewPrivateKey(btcec.S256())
			if err != nil {
				t.Errorf("failed to make privKey for %s: %v",
					msg, err)
				break
			}

			pk := (*btcec.PublicKey)(&key.PublicKey).
				SerializeUncompressed()
			address, err := btcutil.NewAddressPubKeyHash(
				btcutil.Hash160(pk), &chaincfg.TestNet3Params)
			if err != nil {
				t.Errorf("failed to make address for %s: %v",
					msg, err)
				break
			}

			pkScript, err := txscript.PayToAddrScript(address)
			if err != nil {
				t.Errorf("failed to make pkscript "+
					"for %s: %v", msg, err)
				break
			}

			scriptAddr, err := btcutil.NewAddressScriptHash(
				pkScript, &chaincfg.TestNet3Params)
			if err != nil {
				t.Errorf("failed to make p2sh addr for %s: %v",
					msg, err)
				break
			}

			scriptPkScript, err := txscript.PayToAddrScript(
				scriptAddr)
			if err != nil {
				t.Errorf("failed to make script pkscript for "+
					"%s: %v", msg, err)
				break
			}

			if err := signAndCheck(msg, tx, i, scriptPkScript,
				hashType,
				mkGetKey(map[string]addressToKey{
					address.EncodeAddress(): {key, false},
				}), mkGetScript(map[string][]byte{
					scriptAddr.EncodeAddress(): pkScript,
				}), nil); err != nil {
				t.Error(err)
				break
			}
		}
	}

	// Pay to Pubkey Hash (uncompressed) with duplicate merge
	for _, hashType := range hashTypes {
		for i := range tx.TxIn {
			msg := fmt.Sprintf("%d:%d", hashType, i)
			key, err := btcec.NewPrivateKey(btcec.S256())
			if err != nil {
				t.Errorf("failed to make privKey for %s: %v",
					msg, err)
				break
			}

			pk := (*btcec.PublicKey)(&key.PublicKey).
				SerializeUncompressed()
			address, err := btcutil.NewAddressPubKeyHash(
				btcutil.Hash160(pk), &chaincfg.TestNet3Params)
			if err != nil {
				t.Errorf("failed to make address for %s: %v",
					msg, err)
				break
			}

			pkScript, err := txscript.PayToAddrScript(address)
			if err != nil {
				t.Errorf("failed to make pkscript "+
					"for %s: %v", msg, err)
				break
			}

			scriptAddr, err := btcutil.NewAddressScriptHash(
				pkScript, &chaincfg.TestNet3Params)
			if err != nil {
				t.Errorf("failed to make p2sh addr for %s: %v",
					msg, err)
				break
			}

			scriptPkScript, err := txscript.PayToAddrScript(
				scriptAddr)
			if err != nil {
				t.Errorf("failed to make script pkscript for "+
					"%s: %v", msg, err)
				break
			}

			sigScript, err := txscript.SignTxOutput(
				&chaincfg.TestNet3Params, tx, i, scriptPkScript,
				hashType, mkGetKey(map[string]addressToKey{
					address.EncodeAddress(): {key, false},
				}), mkGetScript(map[string][]byte{
					scriptAddr.EncodeAddress(): pkScript,
				}), nil)
			if err != nil {
				t.Errorf("failed to sign output %s: %v", msg,
					err)
				break
			}

			// by the above loop, this should be valid, now sign
			// again and merge.
			sigScript, err = txscript.SignTxOutput(
				&chaincfg.TestNet3Params, tx, i, scriptPkScript,
				hashType, mkGetKey(map[string]addressToKey{
					address.EncodeAddress(): {key, false},
				}), mkGetScript(map[string][]byte{
					scriptAddr.EncodeAddress(): pkScript,
				}), nil)
			if err != nil {
				t.Errorf("failed to sign output %s a "+
					"second time: %v", msg, err)
				break
			}

			err = checkScripts(msg, tx, i, sigScript, scriptPkScript)
			if err != nil {
				t.Errorf("twice signed script invalid for "+
					"%s: %v", msg, err)
				break
			}
		}
	}

	// Pay to Pubkey Hash (compressed)
	for _, hashType := range hashTypes {
		for i := range tx.TxIn {
			msg := fmt.Sprintf("%d:%d", hashType, i)

			key, err := btcec.NewPrivateKey(btcec.S256())
			if err != nil {
				t.Errorf("failed to make privKey for %s: %v",
					msg, err)
				break
			}

			pk := (*btcec.PublicKey)(&key.PublicKey).
				SerializeCompressed()
			address, err := btcutil.NewAddressPubKeyHash(
				btcutil.Hash160(pk), &chaincfg.TestNet3Params)
			if err != nil {
				t.Errorf("failed to make address for %s: %v",
					msg, err)
				break
			}

			pkScript, err := txscript.PayToAddrScript(address)
			if err != nil {
				t.Errorf("failed to make pkscript "+
					"for %s: %v", msg, err)
			}

			scriptAddr, err := btcutil.NewAddressScriptHash(
				pkScript, &chaincfg.TestNet3Params)
			if err != nil {
				t.Errorf("failed to make p2sh addr for %s: %v",
					msg, err)
				break
			}

			scriptPkScript, err := txscript.PayToAddrScript(
				scriptAddr)
			if err != nil {
				t.Errorf("failed to make script pkscript for "+
					"%s: %v", msg, err)
				break
			}

			if err := signAndCheck(msg, tx, i, scriptPkScript,
				hashType,
				mkGetKey(map[string]addressToKey{
					address.EncodeAddress(): {key, true},
				}), mkGetScript(map[string][]byte{
					scriptAddr.EncodeAddress(): pkScript,
				}), nil); err != nil {
				t.Error(err)
				break
			}
		}
	}

	// Pay to Pubkey Hash (compressed) with duplicate merge
	for _, hashType := range hashTypes {
		for i := range tx.TxIn {
			msg := fmt.Sprintf("%d:%d", hashType, i)

			key, err := btcec.NewPrivateKey(btcec.S256())
			if err != nil {
				t.Errorf("failed to make privKey for %s: %v",
					msg, err)
				break
			}

			pk := (*btcec.PublicKey)(&key.PublicKey).
				SerializeCompressed()
			address, err := btcutil.NewAddressPubKeyHash(
				btcutil.Hash160(pk), &chaincfg.TestNet3Params)
			if err != nil {
				t.Errorf("failed to make address for %s: %v",
					msg, err)
				break
			}

			pkScript, err := txscript.PayToAddrScript(address)
			if err != nil {
				t.Errorf("failed to make pkscript "+
					"for %s: %v", msg, err)
			}

			scriptAddr, err := btcutil.NewAddressScriptHash(
				pkScript, &chaincfg.TestNet3Params)
			if err != nil {
				t.Errorf("failed to make p2sh addr for %s: %v",
					msg, err)
				break
			}

			scriptPkScript, err := txscript.PayToAddrScript(
				scriptAddr)
			if err != nil {
				t.Errorf("failed to make script pkscript for "+
					"%s: %v", msg, err)
				break
			}

			sigScript, err := txscript.SignTxOutput(
				&chaincfg.TestNet3Params, tx, i, scriptPkScript,
				hashType, mkGetKey(map[string]addressToKey{
					address.EncodeAddress(): {key, true},
				}), mkGetScript(map[string][]byte{
					scriptAddr.EncodeAddress(): pkScript,
				}), nil)
			if err != nil {
				t.Errorf("failed to sign output %s: %v", msg,
					err)
				break
			}

			// by the above loop, this should be valid, now sign
			// again and merge.
			sigScript, err = txscript.SignTxOutput(
				&chaincfg.TestNet3Params, tx, i, scriptPkScript,
				hashType, mkGetKey(map[string]addressToKey{
					address.EncodeAddress(): {key, true},
				}), mkGetScript(map[string][]byte{
					scriptAddr.EncodeAddress(): pkScript,
				}), nil)
			if err != nil {
				t.Errorf("failed to sign output %s a "+
					"second time: %v", msg, err)
				break
			}

			err = checkScripts(msg, tx, i, sigScript, scriptPkScript)
			if err != nil {
				t.Errorf("twice signed script invalid for "+
					"%s: %v", msg, err)
				break
			}
		}
	}

	// Pay to PubKey (uncompressed)
	for _, hashType := range hashTypes {
		for i := range tx.TxIn {
			msg := fmt.Sprintf("%d:%d", hashType, i)

			key, err := btcec.NewPrivateKey(btcec.S256())
			if err != nil {
				t.Errorf("failed to make privKey for %s: %v",
					msg, err)
				break
			}

			pk := (*btcec.PublicKey)(&key.PublicKey).
				SerializeUncompressed()
			address, err := btcutil.NewAddressPubKey(pk,
				&chaincfg.TestNet3Params)
			if err != nil {
				t.Errorf("failed to make address for %s: %v",
					msg, err)
				break
			}

			pkScript, err := txscript.PayToAddrScript(address)
			if err != nil {
				t.Errorf("failed to make pkscript "+
					"for %s: %v", msg, err)
			}

			scriptAddr, err := btcutil.NewAddressScriptHash(
				pkScript, &chaincfg.TestNet3Params)
			if err != nil {
				t.Errorf("failed to make p2sh addr for %s: %v",
					msg, err)
				break
			}

			scriptPkScript, err := txscript.PayToAddrScript(
				scriptAddr)
			if err != nil {
				t.Errorf("failed to make script pkscript for "+
					"%s: %v", msg, err)
				break
			}

			if err := signAndCheck(msg, tx, i, scriptPkScript,
				hashType,
				mkGetKey(map[string]addressToKey{
					address.EncodeAddress(): {key, false},
				}), mkGetScript(map[string][]byte{
					scriptAddr.EncodeAddress(): pkScript,
				}), nil); err != nil {
				t.Error(err)
				break
			}
		}
	}

	// Pay to PubKey (uncompressed) with duplicate merge
	for _, hashType := range hashTypes {
		for i := range tx.TxIn {
			msg := fmt.Sprintf("%d:%d", hashType, i)

			key, err := btcec.NewPrivateKey(btcec.S256())
			if err != nil {
				t.Errorf("failed to make privKey for %s: %v",
					msg, err)
				break
			}

			pk := (*btcec.PublicKey)(&key.PublicKey).
				SerializeUncompressed()
			address, err := btcutil.NewAddressPubKey(pk,
				&chaincfg.TestNet3Params)
			if err != nil {
				t.Errorf("failed to make address for %s: %v",
					msg, err)
				break
			}

			pkScript, err := txscript.PayToAddrScript(address)
			if err != nil {
				t.Errorf("failed to make pkscript "+
					"for %s: %v", msg, err)
			}

			scriptAddr, err := btcutil.NewAddressScriptHash(
				pkScript, &chaincfg.TestNet3Params)
			if err != nil {
				t.Errorf("failed to make p2sh addr for %s: %v",
					msg, err)
				break
			}

			scriptPkScript, err := txscript.PayToAddrScript(
				scriptAddr)
			if err != nil {
				t.Errorf("failed to make script pkscript for "+
					"%s: %v", msg, err)
				break
			}

			sigScript, err := txscript.SignTxOutput(
				&chaincfg.TestNet3Params, tx, i, scriptPkScript,
				hashType, mkGetKey(map[string]addressToKey{
					address.EncodeAddress(): {key, false},
				}), mkGetScript(map[string][]byte{
					scriptAddr.EncodeAddress(): pkScript,
				}), nil)
			if err != nil {
				t.Errorf("failed to sign output %s: %v", msg,
					err)
				break
			}

			// by the above loop, this should be valid, now sign
			// again and merge.
			sigScript, err = txscript.SignTxOutput(
				&chaincfg.TestNet3Params, tx, i, scriptPkScript,
				hashType, mkGetKey(map[string]addressToKey{
					address.EncodeAddress(): {key, false},
				}), mkGetScript(map[string][]byte{
					scriptAddr.EncodeAddress(): pkScript,
				}), nil)
			if err != nil {
				t.Errorf("failed to sign output %s a "+
					"second time: %v", msg, err)
				break
			}

			err = checkScripts(msg, tx, i, sigScript, scriptPkScript)
			if err != nil {
				t.Errorf("twice signed script invalid for "+
					"%s: %v", msg, err)
				break
			}
		}
	}

	// Pay to PubKey (compressed)
	for _, hashType := range hashTypes {
		for i := range tx.TxIn {
			msg := fmt.Sprintf("%d:%d", hashType, i)

			key, err := btcec.NewPrivateKey(btcec.S256())
			if err != nil {
				t.Errorf("failed to make privKey for %s: %v",
					msg, err)
				break
			}

			pk := (*btcec.PublicKey)(&key.PublicKey).
				SerializeCompressed()
			address, err := btcutil.NewAddressPubKey(pk,
				&chaincfg.TestNet3Params)
			if err != nil {
				t.Errorf("failed to make address for %s: %v",
					msg, err)
				break
			}

			pkScript, err := txscript.PayToAddrScript(address)
			if err != nil {
				t.Errorf("failed to make pkscript "+
					"for %s: %v", msg, err)
			}

			scriptAddr, err := btcutil.NewAddressScriptHash(
				pkScript, &chaincfg.TestNet3Params)
			if err != nil {
				t.Errorf("failed to make p2sh addr for %s: %v",
					msg, err)
				break
			}

			scriptPkScript, err := txscript.PayToAddrScript(
				scriptAddr)
			if err != nil {
				t.Errorf("failed to make script pkscript for "+
					"%s: %v", msg, err)
				break
			}

			if err := signAndCheck(msg, tx, i, scriptPkScript,
				hashType,
				mkGetKey(map[string]addressToKey{
					address.EncodeAddress(): {key, true},
				}), mkGetScript(map[string][]byte{
					scriptAddr.EncodeAddress(): pkScript,
				}), nil); err != nil {
				t.Error(err)
				break
			}
		}
	}

	// Pay to PubKey (compressed)
	for _, hashType := range hashTypes {
		for i := range tx.TxIn {
			msg := fmt.Sprintf("%d:%d", hashType, i)

			key, err := btcec.NewPrivateKey(btcec.S256())
			if err != nil {
				t.Errorf("failed to make privKey for %s: %v",
					msg, err)
				break
			}

			pk := (*btcec.PublicKey)(&key.PublicKey).
				SerializeCompressed()
			address, err := btcutil.NewAddressPubKey(pk,
				&chaincfg.TestNet3Params)
			if err != nil {
				t.Errorf("failed to make address for %s: %v",
					msg, err)
				break
			}

			pkScript, err := txscript.PayToAddrScript(address)
			if err != nil {
				t.Errorf("failed to make pkscript "+
					"for %s: %v", msg, err)
			}

			scriptAddr, err := btcutil.NewAddressScriptHash(
				pkScript, &chaincfg.TestNet3Params)
			if err != nil {
				t.Errorf("failed to make p2sh addr for %s: %v",
					msg, err)
				break
			}

			scriptPkScript, err := txscript.PayToAddrScript(
				scriptAddr)
			if err != nil {
				t.Errorf("failed to make script pkscript for "+
					"%s: %v", msg, err)
				break
			}

			sigScript, err := txscript.SignTxOutput(
				&chaincfg.TestNet3Params, tx, i, scriptPkScript,
				hashType, mkGetKey(map[string]addressToKey{
					address.EncodeAddress(): {key, true},
				}), mkGetScript(map[string][]byte{
					scriptAddr.EncodeAddress(): pkScript,
				}), nil)
			if err != nil {
				t.Errorf("failed to sign output %s: %v", msg,
					err)
				break
			}

			// by the above loop, this should be valid, now sign
			// again and merge.
			sigScript, err = txscript.SignTxOutput(
				&chaincfg.TestNet3Params, tx, i, scriptPkScript,
				hashType, mkGetKey(map[string]addressToKey{
					address.EncodeAddress(): {key, true},
				}), mkGetScript(map[string][]byte{
					scriptAddr.EncodeAddress(): pkScript,
				}), nil)
			if err != nil {
				t.Errorf("failed to sign output %s a "+
					"second time: %v", msg, err)
				break
			}

			err = checkScripts(msg, tx, i, sigScript, scriptPkScript)
			if err != nil {
				t.Errorf("twice signed script invalid for "+
					"%s: %v", msg, err)
				break
			}
		}
	}

	// Basic Multisig
	for _, hashType := range hashTypes {
		for i := range tx.TxIn {
			msg := fmt.Sprintf("%d:%d", hashType, i)

			key1, err := btcec.NewPrivateKey(btcec.S256())
			if err != nil {
				t.Errorf("failed to make privKey for %s: %v",
					msg, err)
				break
			}

			pk1 := (*btcec.PublicKey)(&key1.PublicKey).
				SerializeCompressed()
			address1, err := btcutil.NewAddressPubKey(pk1,
				&chaincfg.TestNet3Params)
			if err != nil {
				t.Errorf("failed to make address for %s: %v",
					msg, err)
				break
			}

			key2, err := btcec.NewPrivateKey(btcec.S256())
			if err != nil {
				t.Errorf("failed to make privKey 2 for %s: %v",
					msg, err)
				break
			}

			pk2 := (*btcec.PublicKey)(&key2.PublicKey).
				SerializeCompressed()
			address2, err := btcutil.NewAddressPubKey(pk2,
				&chaincfg.TestNet3Params)
			if err != nil {
				t.Errorf("failed to make address 2 for %s: %v",
					msg, err)
				break
			}

			pkScript, err := txscript.MultiSigScript(
				[]*btcutil.AddressPubKey{address1, address2},
				2)
			if err != nil {
				t.Errorf("failed to make pkscript "+
					"for %s: %v", msg, err)
			}

			scriptAddr, err := btcutil.NewAddressScriptHash(
				pkScript, &chaincfg.TestNet3Params)
			if err != nil {
				t.Errorf("failed to make p2sh addr for %s: %v",
					msg, err)
				break
			}

			scriptPkScript, err := txscript.PayToAddrScript(
				scriptAddr)
			if err != nil {
				t.Errorf("failed to make script pkscript for "+
					"%s: %v", msg, err)
				break
			}

			if err := signAndCheck(msg, tx, i, scriptPkScript,
				hashType,
				mkGetKey(map[string]addressToKey{
					address1.EncodeAddress(): {key1, true},
					address2.EncodeAddress(): {key2, true},
				}), mkGetScript(map[string][]byte{
					scriptAddr.EncodeAddress(): pkScript,
				}), nil); err != nil {
				t.Error(err)
				break
			}
		}
	}

	// Two part multisig, sign with one key then the other.
	for _, hashType := range hashTypes {
		for i := range tx.TxIn {
			msg := fmt.Sprintf("%d:%d", hashType, i)

			key1, err := btcec.NewPrivateKey(btcec.S256())
			if err != nil {
				t.Errorf("failed to make privKey for %s: %v",
					msg, err)
				break
			}

			pk1 := (*btcec.PublicKey)(&key1.PublicKey).
				SerializeCompressed()
			address1, err := btcutil.NewAddressPubKey(pk1,
				&chaincfg.TestNet3Params)
			if err != nil {
				t.Errorf("failed to make address for %s: %v",
					msg, err)
				break
			}

			key2, err := btcec.NewPrivateKey(btcec.S256())
			if err != nil {
				t.Errorf("failed to make privKey 2 for %s: %v",
					msg, err)
				break
			}

			pk2 := (*btcec.PublicKey)(&key2.PublicKey).
				SerializeCompressed()
			address2, err := btcutil.NewAddressPubKey(pk2,
				&chaincfg.TestNet3Params)
			if err != nil {
				t.Errorf("failed to make address 2 for %s: %v",
					msg, err)
				break
			}

			pkScript, err := txscript.MultiSigScript(
				[]*btcutil.AddressPubKey{address1, address2},
				2)
			if err != nil {
				t.Errorf("failed to make pkscript "+
					"for %s: %v", msg, err)
			}

			scriptAddr, err := btcutil.NewAddressScriptHash(
				pkScript, &chaincfg.TestNet3Params)
			if err != nil {
				t.Errorf("failed to make p2sh addr for %s: %v",
					msg, err)
				break
			}

			scriptPkScript, err := txscript.PayToAddrScript(
				scriptAddr)
			if err != nil {
				t.Errorf("failed to make script pkscript for "+
					"%s: %v", msg, err)
				break
			}

			sigScript, err := txscript.SignTxOutput(
				&chaincfg.TestNet3Params, tx, i, scriptPkScript,
				hashType, mkGetKey(map[string]addressToKey{
					address1.EncodeAddress(): {key1, true},
				}), mkGetScript(map[string][]byte{
					scriptAddr.EncodeAddress(): pkScript,
				}), nil)
			if err != nil {
				t.Errorf("failed to sign output %s: %v", msg,
					err)
				break
			}

			// Only 1 out of 2 signed, this *should* fail.
			if checkScripts(msg, tx, i, sigScript,
				scriptPkScript) == nil {
				t.Errorf("part signed script valid for %s", msg)
				break
			}

			// Sign with the other key and merge
			sigScript, err = txscript.SignTxOutput(
				&chaincfg.TestNet3Params, tx, i, scriptPkScript,
				hashType, mkGetKey(map[string]addressToKey{
					address2.EncodeAddress(): {key2, true},
				}), mkGetScript(map[string][]byte{
					scriptAddr.EncodeAddress(): pkScript,
				}), sigScript)
			if err != nil {
				t.Errorf("failed to sign output %s: %v", msg, err)
				break
			}

			err = checkScripts(msg, tx, i, sigScript,
				scriptPkScript)
			if err != nil {
				t.Errorf("fully signed script invalid for "+
					"%s: %v", msg, err)
				break
			}
		}
	}

	// Two part multisig, sign with one key then both, check key dedup
	// correctly.
	for _, hashType := range hashTypes {
		for i := range tx.TxIn {
			msg := fmt.Sprintf("%d:%d", hashType, i)

			key1, err := btcec.NewPrivateKey(btcec.S256())
			if err != nil {
				t.Errorf("failed to make privKey for %s: %v",
					msg, err)
				break
			}

			pk1 := (*btcec.PublicKey)(&key1.PublicKey).
				SerializeCompressed()
			address1, err := btcutil.NewAddressPubKey(pk1,
				&chaincfg.TestNet3Params)
			if err != nil {
				t.Errorf("failed to make address for %s: %v",
					msg, err)
				break
			}

			key2, err := btcec.NewPrivateKey(btcec.S256())
			if err != nil {
				t.Errorf("failed to make privKey 2 for %s: %v",
					msg, err)
				break
			}

			pk2 := (*btcec.PublicKey)(&key2.PublicKey).
				SerializeCompressed()
			address2, err := btcutil.NewAddressPubKey(pk2,
				&chaincfg.TestNet3Params)
			if err != nil {
				t.Errorf("failed to make address 2 for %s: %v",
					msg, err)
				break
			}

			pkScript, err := txscript.MultiSigScript(
				[]*btcutil.AddressPubKey{address1, address2},
				2)
			if err != nil {
				t.Errorf("failed to make pkscript "+
					"for %s: %v", msg, err)
			}

			scriptAddr, err := btcutil.NewAddressScriptHash(
				pkScript, &chaincfg.TestNet3Params)
			if err != nil {
				t.Errorf("failed to make p2sh addr for %s: %v",
					msg, err)
				break
			}

			scriptPkScript, err := txscript.PayToAddrScript(
				scriptAddr)
			if err != nil {
				t.Errorf("failed to make script pkscript for "+
					"%s: %v", msg, err)
				break
			}

			sigScript, err := txscript.SignTxOutput(
				&chaincfg.TestNet3Params, tx, i, scriptPkScript,
				hashType, mkGetKey(map[string]addressToKey{
					address1.EncodeAddress(): {key1, true},
				}), mkGetScript(map[string][]byte{
					scriptAddr.EncodeAddress(): pkScript,
				}), nil)
			if err != nil {
				t.Errorf("failed to sign output %s: %v", msg,
					err)
				break
			}

			// Only 1 out of 2 signed, this *should* fail.
			if checkScripts(msg, tx, i, sigScript,
				scriptPkScript) == nil {
				t.Errorf("part signed script valid for %s", msg)
				break
			}

			// Sign with the other key and merge
			sigScript, err = txscript.SignTxOutput(
				&chaincfg.TestNet3Params, tx, i, scriptPkScript,
				hashType, mkGetKey(map[string]addressToKey{
					address1.EncodeAddress(): {key1, true},
					address2.EncodeAddress(): {key2, true},
				}), mkGetScript(map[string][]byte{
					scriptAddr.EncodeAddress(): pkScript,
				}), sigScript)
			if err != nil {
				t.Errorf("failed to sign output %s: %v", msg, err)
				break
			}

			// Now we should pass.
			err = checkScripts(msg, tx, i, sigScript,
				scriptPkScript)
			if err != nil {
				t.Errorf("fully signed script invalid for "+
					"%s: %v", msg, err)
				break
			}
		}
	}
}
示例#5
0
// This example demonstrates manually creating and signing a redeem transaction.
func ExampleSignTxOutput() {
	// Ordinarily the private key would come from whatever storage mechanism
	// is being used, but for this example just hard code it.
	privKeyBytes, err := hex.DecodeString("22a47fa09a223f2aa079edf85a7c2" +
		"d4f8720ee63e502ee2869afab7de234b80c")
	if err != nil {
		fmt.Println(err)
		return
	}
	privKey, pubKey := btcec.PrivKeyFromBytes(btcec.S256(), privKeyBytes)
	pubKeyHash := btcutil.Hash160(pubKey.SerializeCompressed())
	addr, err := btcutil.NewAddressPubKeyHash(pubKeyHash,
		&chaincfg.MainNetParams)
	if err != nil {
		fmt.Println(err)
		return
	}

	// For this example, create a fake transaction that represents what
	// would ordinarily be the real transaction that is being spent.  It
	// contains a single output that pays to address in the amount of 1 BTC.
	originTx := wire.NewMsgTx()
	prevOut := wire.NewOutPoint(&wire.ShaHash{}, ^uint32(0))
	txIn := wire.NewTxIn(prevOut, []byte{txscript.OP_0, txscript.OP_0})
	originTx.AddTxIn(txIn)
	pkScript, err := txscript.PayToAddrScript(addr)
	if err != nil {
		fmt.Println(err)
		return
	}
	txOut := wire.NewTxOut(100000000, pkScript)
	originTx.AddTxOut(txOut)
	originTxHash := originTx.TxSha()

	// Create the transaction to redeem the fake transaction.
	redeemTx := wire.NewMsgTx()

	// Add the input(s) the redeeming transaction will spend.  There is no
	// signature script at this point since it hasn't been created or signed
	// yet, hence nil is provided for it.
	prevOut = wire.NewOutPoint(&originTxHash, 0)
	txIn = wire.NewTxIn(prevOut, nil)
	redeemTx.AddTxIn(txIn)

	// Ordinarily this would contain that actual destination of the funds,
	// but for this example don't bother.
	txOut = wire.NewTxOut(0, nil)
	redeemTx.AddTxOut(txOut)

	// Sign the redeeming transaction.
	lookupKey := func(a btcutil.Address) (*btcec.PrivateKey, bool, error) {
		// Ordinarily this function would involve looking up the private
		// key for the provided address, but since the only thing being
		// signed in this example uses the address associated with the
		// private key from above, simply return it with the compressed
		// flag set since the address is using the associated compressed
		// public key.
		//
		// NOTE: If you want to prove the code is actually signing the
		// transaction properly, uncomment the following line which
		// intentionally returns an invalid key to sign with, which in
		// turn will result in a failure during the script execution
		// when verifying the signature.
		//
		// privKey.D.SetInt64(12345)
		//
		return privKey, true, nil
	}
	// Notice that the script database parameter is nil here since it isn't
	// used.  It must be specified when pay-to-script-hash transactions are
	// being signed.
	sigScript, err := txscript.SignTxOutput(&chaincfg.MainNetParams,
		redeemTx, 0, originTx.TxOut[0].PkScript, txscript.SigHashAll,
		txscript.KeyClosure(lookupKey), nil, nil)
	if err != nil {
		fmt.Println(err)
		return
	}
	redeemTx.TxIn[0].SignatureScript = sigScript

	// Prove that the transaction has been validly signed by executing the
	// script pair.
	flags := txscript.ScriptBip16 | txscript.ScriptVerifyDERSignatures |
		txscript.ScriptStrictMultiSig |
		txscript.ScriptDiscourageUpgradableNops
	vm, err := txscript.NewEngine(originTx.TxOut[0].PkScript, redeemTx, 0,
		flags)
	if err != nil {
		fmt.Println(err)
		return
	}
	if err := vm.Execute(); err != nil {
		fmt.Println(err)
		return
	}
	fmt.Println("Transaction successfully signed")

	// Output:
	// Transaction successfully signed
}
// Address converts the extended key to a standard bitcoin pay-to-pubkey-hash
// address for the passed network.
func (k *ExtendedKey) Address(net *chaincfg.Params) (*btcutil.AddressPubKeyHash, error) {
	pkHash := btcutil.Hash160(k.pubKeyBytes())
	return btcutil.NewAddressPubKeyHash(pkHash, net)
}
// 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
}