135 lines
3.9 KiB
Go
135 lines
3.9 KiB
Go
package lnwallet
|
|
|
|
import (
|
|
"encoding/binary"
|
|
"io"
|
|
|
|
"github.com/lightningnetwork/lnd/lnwire"
|
|
"github.com/roasbeef/btcd/btcec"
|
|
"github.com/roasbeef/btcd/txscript"
|
|
"github.com/roasbeef/btcd/wire"
|
|
)
|
|
|
|
// SignDescriptor houses the necessary information required to successfully sign
|
|
// a given output. This struct is used by the Signer interface in order to gain
|
|
// access to critical data needed to generate a valid signature.
|
|
type SignDescriptor struct {
|
|
// Pubkey is the public key to which the signature should be generated
|
|
// over. The Signer should then generate a signature with the private
|
|
// key corresponding to this public key.
|
|
PubKey *btcec.PublicKey
|
|
|
|
// PrivateTweak is a scalar value that should be added to the private
|
|
// key corresponding to the above public key to obtain the private key
|
|
// to be used to sign this input. This value is typically a leaf node
|
|
// from the revocation tree.
|
|
//
|
|
// NOTE: If this value is nil, then the input can be signed using only
|
|
// the above public key.
|
|
PrivateTweak []byte
|
|
|
|
// WitnessScript is the full script required to properly redeem the
|
|
// output. This field will only be populated if a p2wsh or a p2sh
|
|
// output is being signed.
|
|
WitnessScript []byte
|
|
|
|
// Output is the target output which should be signed. The PkScript and
|
|
// Value fields within the output should be properly populated,
|
|
// otherwise an invalid signature may be generated.
|
|
Output *wire.TxOut
|
|
|
|
// HashType is the target sighash type that should be used when
|
|
// generating the final sighash, and signature.
|
|
HashType txscript.SigHashType
|
|
|
|
// SigHashes is the pre-computed sighash midstate to be used when
|
|
// generating the final sighash for signing.
|
|
SigHashes *txscript.TxSigHashes
|
|
|
|
// InputIndex is the target input within the transaction that should be
|
|
// signed.
|
|
InputIndex int
|
|
}
|
|
|
|
// WriteSignDescriptor serializes a SignDescriptor struct into the passed
|
|
// io.Writer stream.
|
|
// NOTE: We assume the SigHashes and InputIndex fields haven't been assigned
|
|
// yet, since that is usually done just before broadcast by the witness
|
|
// generator.
|
|
func WriteSignDescriptor(w io.Writer, sd *SignDescriptor) error {
|
|
serializedPubKey := sd.PubKey.SerializeCompressed()
|
|
if err := wire.WriteVarBytes(w, 0, serializedPubKey); err != nil {
|
|
return err
|
|
}
|
|
|
|
if err := wire.WriteVarBytes(w, 0, sd.PrivateTweak); err != nil {
|
|
return err
|
|
}
|
|
|
|
if err := wire.WriteVarBytes(w, 0, sd.WitnessScript); err != nil {
|
|
return err
|
|
}
|
|
|
|
if err := lnwire.WriteTxOut(w, sd.Output); err != nil {
|
|
return err
|
|
}
|
|
|
|
var scratch [4]byte
|
|
binary.BigEndian.PutUint32(scratch[:], uint32(sd.HashType))
|
|
if _, err := w.Write(scratch[:]); err != nil {
|
|
return err
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// ReadSignDescriptor deserializes a SignDescriptor struct from the passed
|
|
// io.Reader stream.
|
|
func ReadSignDescriptor(r io.Reader, sd *SignDescriptor) error {
|
|
|
|
pubKeyBytes, err := wire.ReadVarBytes(r, 0, 34, "pubkey")
|
|
if err != nil {
|
|
return err
|
|
}
|
|
sd.PubKey, err = btcec.ParsePubKey(pubKeyBytes, btcec.S256())
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
privateTweak, err := wire.ReadVarBytes(r, 0, 32, "privateTweak")
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
// Serializing a SignDescriptor with a nil-valued PrivateTweak results in
|
|
// deserializing a zero-length slice. Since a nil-valued PrivateTweak has
|
|
// special meaning and a zero-length slice for a PrivateTweak is invalid,
|
|
// we can use the zero-length slice as the flag for a nil-valued
|
|
// PrivateTweak.
|
|
if len(privateTweak) == 0 {
|
|
sd.PrivateTweak = nil
|
|
} else {
|
|
sd.PrivateTweak = privateTweak
|
|
}
|
|
|
|
witnessScript, err := wire.ReadVarBytes(r, 0, 100, "witnessScript")
|
|
if err != nil {
|
|
return err
|
|
}
|
|
sd.WitnessScript = witnessScript
|
|
|
|
txOut := &wire.TxOut{}
|
|
if err := lnwire.ReadTxOut(r, txOut); err != nil {
|
|
return err
|
|
}
|
|
sd.Output = txOut
|
|
|
|
var hashType [4]byte
|
|
if _, err := io.ReadFull(r, hashType[:]); err != nil {
|
|
return err
|
|
}
|
|
sd.HashType = txscript.SigHashType(binary.BigEndian.Uint32(hashType[:]))
|
|
|
|
return nil
|
|
}
|