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