lnd.xprv/my/btcutil/psbt/bip32.go

78 lines
2.3 KiB
Go

package psbt
import (
"bytes"
"encoding/binary"
)
// Bip32Derivation encapsulates the data for the input and output
// Bip32Derivation key-value fields.
//
// TODO(roasbeef): use hdkeychain here instead?
type Bip32Derivation struct {
// PubKey is the raw pubkey serialized in compressed format.
PubKey []byte
// MasterKeyFingerprint is the finger print of the master pubkey.
MasterKeyFingerprint uint32
// Bip32Path is the BIP 32 path with child index as a distinct integer.
Bip32Path []uint32
}
// checkValid ensures that the PubKey in the Bip32Derivation struct is valid.
func (pb *Bip32Derivation) checkValid() bool {
return validatePubkey(pb.PubKey)
}
// Bip32Sorter implements sort.Interface for the Bip32Derivation struct.
type Bip32Sorter []*Bip32Derivation
func (s Bip32Sorter) Len() int { return len(s) }
func (s Bip32Sorter) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
func (s Bip32Sorter) Less(i, j int) bool {
return bytes.Compare(s[i].PubKey, s[j].PubKey) < 0
}
// readBip32Derivation deserializes a byte slice containing chunks of 4 byte
// little endian encodings of uint32 values, the first of which is the
// masterkeyfingerprint and the remainder of which are the derivation path.
func readBip32Derivation(path []byte) (uint32, []uint32, error) {
if len(path)%4 != 0 || len(path)/4-1 < 1 {
return 0, nil, ErrInvalidPsbtFormat
}
masterKeyInt := binary.LittleEndian.Uint32(path[:4])
var paths []uint32
for i := 4; i < len(path); i += 4 {
paths = append(paths, binary.LittleEndian.Uint32(path[i:i+4]))
}
return masterKeyInt, paths, nil
}
// SerializeBIP32Derivation takes a master key fingerprint as defined in BIP32,
// along with a path specified as a list of uint32 values, and returns a
// bytestring specifying the derivation in the format required by BIP174: //
// master key fingerprint (4) || child index (4) || child index (4) || ....
func SerializeBIP32Derivation(masterKeyFingerprint uint32,
bip32Path []uint32) []byte {
var masterKeyBytes [4]byte
binary.LittleEndian.PutUint32(masterKeyBytes[:], masterKeyFingerprint)
derivationPath := make([]byte, 0, 4+4*len(bip32Path))
derivationPath = append(derivationPath, masterKeyBytes[:]...)
for _, path := range bip32Path {
var pathbytes [4]byte
binary.LittleEndian.PutUint32(pathbytes[:], path)
derivationPath = append(derivationPath, pathbytes[:]...)
}
return derivationPath
}