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sign.go
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sign.go
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// Copyright (c) 2013-2015 The btcsuite developers
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package txscript
import (
"github.com/pkg/errors"
"github.com/romxxxx/go-secp256k1"
"github.com/romxxxx/nexepad/domain/consensus/model/externalapi"
"github.com/romxxxx/nexepad/domain/consensus/utils/consensushashing"
"github.com/romxxxx/nexepad/domain/dagconfig"
"github.com/romxxxx/nexepad/util"
)
// RawTxInSignature returns the serialized Schnorr signature for the input idx of
// the given transaction, with hashType appended to it.
func RawTxInSignature(tx *externalapi.DomainTransaction, idx int, hashType consensushashing.SigHashType,
key *secp256k1.SchnorrKeyPair, sighashReusedValues *consensushashing.SighashReusedValues) ([]byte, error) {
hash, err := consensushashing.CalculateSignatureHashSchnorr(tx, idx, hashType, sighashReusedValues)
if err != nil {
return nil, err
}
secpHash := secp256k1.Hash(*hash.ByteArray())
signature, err := key.SchnorrSign(&secpHash)
if err != nil {
return nil, errors.Errorf("cannot sign tx input: %s", err)
}
return append(signature.Serialize()[:], byte(hashType)), nil
}
// RawTxInSignatureECDSA returns the serialized ECDSA signature for the input idx of
// the given transaction, with hashType appended to it.
func RawTxInSignatureECDSA(tx *externalapi.DomainTransaction, idx int, hashType consensushashing.SigHashType,
key *secp256k1.ECDSAPrivateKey, sighashReusedValues *consensushashing.SighashReusedValues) ([]byte, error) {
hash, err := consensushashing.CalculateSignatureHashECDSA(tx, idx, hashType, sighashReusedValues)
if err != nil {
return nil, err
}
secpHash := secp256k1.Hash(*hash.ByteArray())
signature, err := key.ECDSASign(&secpHash)
if err != nil {
return nil, errors.Errorf("cannot sign tx input: %s", err)
}
return append(signature.Serialize()[:], byte(hashType)), nil
}
// SignatureScript creates an input signature script for tx to spend nexe sent
// from a previous output to the owner of a Schnorr private key. tx must include all
// transaction inputs and outputs, however txin scripts are allowed to be filled
// or empty. The returned script is calculated to be used as the idx'th txin
// sigscript for tx. script is the ScriptPublicKey of the previous output being used
// as the idx'th input. privKey is serialized in either a compressed or
// uncompressed format based on compress. This format must match the same format
// used to generate the payment address, or the script validation will fail.
func SignatureScript(tx *externalapi.DomainTransaction, idx int, hashType consensushashing.SigHashType,
privKey *secp256k1.SchnorrKeyPair, sighashReusedValues *consensushashing.SighashReusedValues) ([]byte, error) {
sig, err := RawTxInSignature(tx, idx, hashType, privKey, sighashReusedValues)
if err != nil {
return nil, err
}
return NewScriptBuilder().AddData(sig).Script()
}
// SignatureScriptECDSA creates an input signature script for tx to spend nexe sent
// from a previous output to the owner of an ECDSA private key. tx must include all
// transaction inputs and outputs, however txin scripts are allowed to be filled
// or empty. The returned script is calculated to be used as the idx'th txin
// sigscript for tx. script is the ScriptPublicKey of the previous output being used
// as the idx'th input. privKey is serialized in either a compressed or
// uncompressed format based on compress. This format must match the same format
// used to generate the payment address, or the script validation will fail.
func SignatureScriptECDSA(tx *externalapi.DomainTransaction, idx int, hashType consensushashing.SigHashType,
privKey *secp256k1.ECDSAPrivateKey, sighashReusedValues *consensushashing.SighashReusedValues) ([]byte, error) {
sig, err := RawTxInSignatureECDSA(tx, idx, hashType, privKey, sighashReusedValues)
if err != nil {
return nil, err
}
return NewScriptBuilder().AddData(sig).Script()
}
func sign(dagParams *dagconfig.Params, tx *externalapi.DomainTransaction, idx int,
script *externalapi.ScriptPublicKey, hashType consensushashing.SigHashType,
sighashReusedValues *consensushashing.SighashReusedValues, kdb KeyDB, sdb ScriptDB) (
[]byte, ScriptClass, util.Address, error) {
class, address, err := ExtractScriptPubKeyAddress(script, dagParams)
if err != nil {
return nil, NonStandardTy, nil, err
}
switch class {
case PubKeyTy:
// look up key for address
key, err := kdb.GetKey(address)
if err != nil {
return nil, class, nil, err
}
signedScript, err := SignatureScript(tx, idx, hashType, key, sighashReusedValues)
if err != nil {
return nil, class, nil, err
}
return signedScript, class, address, nil
case ScriptHashTy:
script, err := sdb.GetScript(address)
if err != nil {
return nil, class, nil, err
}
return script, class, address, nil
default:
return nil, class, nil, errors.New("can't sign unknown transactions")
}
}
// mergeScripts merges sigScript and prevScript assuming they are both
// partial solutions for scriptPubKey spending output idx of tx. class, addresses
// and nrequired are the result of extracting the addresses from scriptPubKey.
// The return value is the best effort merging of the two scripts. Calling this
// function with addresses, class and nrequired that do not match scriptPubKey is
// an error and results in undefined behaviour.
func mergeScripts(dagParams *dagconfig.Params, tx *externalapi.DomainTransaction, idx int,
class ScriptClass, sigScript []byte, prevScript *externalapi.ScriptPublicKey) ([]byte, error) {
switch class {
case ScriptHashTy:
// Remove the last push in the script and then recurse.
// this could be a lot less inefficient.
sigPops, err := parseScript(sigScript)
if err != nil || len(sigPops) == 0 {
return prevScript.Script, nil
}
prevPops, err := parseScript(prevScript.Script)
if err != nil || len(prevPops) == 0 {
return sigScript, nil
}
// assume that script in sigPops is the correct one, we just
// made it.
script := sigPops[len(sigPops)-1].data
scriptPubKey := &externalapi.ScriptPublicKey{
Script: script,
Version: prevScript.Version,
}
// We already know this information somewhere up the stack.
class, _, _ :=
ExtractScriptPubKeyAddress(scriptPubKey, dagParams)
// regenerate scripts.
sigScript, _ := unparseScript(sigPops)
prevScriptByte, _ := unparseScript(prevPops)
prevScript = &externalapi.ScriptPublicKey{
Script: prevScriptByte,
Version: prevScript.Version,
}
// Merge
mergedScript, err := mergeScripts(dagParams, tx, idx, class, sigScript, prevScript)
if err != nil {
return nil, err
}
// Reappend the script and return the result.
builder := NewScriptBuilder()
builder.AddOps(mergedScript)
builder.AddData(script)
return builder.Script()
// It doesn't actually make sense to merge anything other than multiig
// and scripthash (because it could contain multisig). Everything else
// has either zero signature, can't be spent, or has a single signature
// which is either present or not. The other two cases are handled
// above. In the conflict case here we just assume the longest is
// correct (this matches behaviour of the reference implementation).
default:
if len(sigScript) > len(prevScript.Script) {
return sigScript, nil
}
return prevScript.Script, nil
}
}
// KeyDB is an interface type provided to SignTxOutput, it encapsulates
// any user state required to get the private keys for an address.
type KeyDB interface {
GetKey(util.Address) (*secp256k1.SchnorrKeyPair, error)
}
// KeyClosure implements KeyDB with a closure.
type KeyClosure func(util.Address) (*secp256k1.SchnorrKeyPair, error)
// GetKey implements KeyDB by returning the result of calling the closure.
func (kc KeyClosure) GetKey(address util.Address) (*secp256k1.SchnorrKeyPair, error) {
return kc(address)
}
// ScriptDB is an interface type provided to SignTxOutput, it encapsulates any
// user state required to get the scripts for an pay-to-script-hash address.
type ScriptDB interface {
GetScript(util.Address) ([]byte, error)
}
// ScriptClosure implements ScriptDB with a closure.
type ScriptClosure func(util.Address) ([]byte, error)
// GetScript implements ScriptDB by returning the result of calling the closure.
func (sc ScriptClosure) GetScript(address util.Address) ([]byte, error) {
return sc(address)
}
// SignTxOutput signs output idx of the given tx to resolve the script given in
// scriptPublicKey with a signature type of hashType. Any keys required will be
// looked up by calling getKey() with the string of the given address.
// Any pay-to-script-hash signatures will be similarly looked up by calling
// getScript. If previousScript is provided then the results in previousScript
// will be merged in a type-dependent manner with the newly generated.
// signature script.
func SignTxOutput(dagParams *dagconfig.Params, tx *externalapi.DomainTransaction, idx int,
scriptPublicKey *externalapi.ScriptPublicKey, hashType consensushashing.SigHashType,
sighashReusedValues *consensushashing.SighashReusedValues, kdb KeyDB, sdb ScriptDB,
previousScript *externalapi.ScriptPublicKey) ([]byte, error) {
sigScript, class, _, err := sign(dagParams, tx,
idx, scriptPublicKey, hashType, sighashReusedValues, kdb, sdb)
if err != nil {
return nil, err
}
if class == ScriptHashTy {
scriptHashPreimageScriptPublicKey := &externalapi.ScriptPublicKey{
Script: sigScript,
Version: scriptPublicKey.Version,
}
realSigScript, _, _, err := sign(dagParams, tx, idx,
scriptHashPreimageScriptPublicKey, hashType, sighashReusedValues, kdb, sdb)
if err != nil {
return nil, err
}
// Append the p2sh script as the last push in the script.
builder := NewScriptBuilder()
builder.AddOps(realSigScript)
builder.AddData(sigScript)
sigScript, _ = builder.Script()
}
// Merge scripts. with any previous data, if any.
return mergeScripts(dagParams, tx, idx, class, sigScript, previousScript)
}