genimportscript: add Electrum format, write result to file

Author: guggero

btc/bitcoind.go

@@ -3,6 +3,7 @@ package btc
 import (
 	"fmt"
 	"io"
+	"strings"
 	"time"
 
 	"github.com/btcsuite/btcd/chaincfg"
@@ -16,6 +17,7 @@ const (
 	FormatCli          = "bitcoin-cli"
 	FormatCliWatchOnly = "bitcoin-cli-watchonly"
 	FormatImportwallet = "bitcoin-importwallet"
+	FormatElectrum     = "electrum"
 )
 
 type KeyExporter interface {
@@ -40,6 +42,9 @@ func ParseFormat(format string) KeyExporter {
 
 	case FormatImportwallet:
 		return &ImportWallet{}
+
+	case FormatElectrum:
+		return &Electrum{}
 	}
 }
 
@@ -215,3 +220,35 @@ func (i *ImportWallet) Format(hdKey *hdkeychain.ExtendedKey,
 func (i *ImportWallet) Trailer(_ uint32) string {
 	return ""
 }
+
+type Electrum struct{}
+
+func (p *Electrum) Header() string {
+	return "# Copy the content of this file (without this line) into " +
+		"Electrum."
+}
+
+func (p *Electrum) Format(hdKey *hdkeychain.ExtendedKey,
+	params *chaincfg.Params, path string, branch, index uint32) (string,
+	error) {
+
+	privKey, err := hdKey.ECPrivKey()
+	if err != nil {
+		return "", fmt.Errorf("could not derive private key: %v", err)
+	}
+	wif, err := btcutil.NewWIF(privKey, params, true)
+	if err != nil {
+		return "", fmt.Errorf("could not encode WIF: %v", err)
+	}
+
+	prefix := "p2wpkh"
+	if strings.HasPrefix(path, lnd.WalletBIP49DerivationPath) {
+		prefix = "p2wpkh-p2sh"
+	}
+	
+	return fmt.Sprintf("%s:%s", prefix, wif.String()), nil
+}
+
+func (p *Electrum) Trailer(_ uint32) string {
+	return ""
+}

cmd/chantools/genimportscript.go

@@ -21,6 +21,7 @@ type genImportScriptCommand struct {
 	DerivationPath string
 	RecoveryWindow uint32
 	RescanFrom     uint32
+	Stdout         bool
 
 	rootKey *rootKey
 	cmd     *cobra.Command
@@ -46,16 +47,18 @@ The following script formats are currently supported:
   imported into bitcoind to watch the UTXOs of those keys. The funds cannot be
   spent that way as they are watch-only.
 * bitcoin-importwallet: Creates a text output that is compatible with
-  bitcoind's importwallet command.`,
+  bitcoind's importwallet command.
+* electrum: Creates a text output that contains one private key per line with
+  the address type as the prefix, the way Electrum expects them.`,
 		Example: `chantools genimportscript --format bitcoin-cli \
 	--recoverywindow 5000`,
 		RunE: cc.Execute,
 	}
 	cc.cmd.Flags().StringVar(
 		&cc.Format, "format", "bitcoin-importwallet", "format of the "+
 			"generated import script; currently supported are: "+
-			"bitcoin-importwallet, bitcoin-cli and "+
-			"bitcoin-cli-watchonly",
+			"bitcoin-importwallet, bitcoin-cli, "+
+			"bitcoin-cli-watchonly and electrum",
 	)
 	cc.cmd.Flags().BoolVar(
 		&cc.LndPaths, "lndpaths", false, "use all derivation paths "+
@@ -79,6 +82,9 @@ The following script formats are currently supported:
 			"from the wallet birthday if the lnd 24 word aezeed "+
 			"is entered",
 	)
+	cc.cmd.Flags().BoolVar(
+		&cc.Stdout, "stdout", false, "write generated import script "+
+			"to standard out instead of writing it to a file")
 
 	cc.rootKey = newRootKey(cc.cmd, "decrypting the backup")
 
@@ -137,10 +143,25 @@ func (c *genImportScriptCommand) Execute(_ *cobra.Command, _ []string) error {
 		}
 	}
 
+	writer := os.Stdout
+	if !c.Stdout {
+		fileName := fmt.Sprintf("results/genimportscript-%s.txt",
+			time.Now().Format("2006-01-02-15-04-05"))
+		log.Infof("Writing import script with format '%s' to %s",
+			c.Format, fileName)
+
+		var err error
+		writer, err = os.Create(fileName)
+		if err != nil {
+			return fmt.Errorf("error creating result file %s: %v",
+				fileName, err)
+		}
+	}
+
 	exporter := btc.ParseFormat(c.Format)
 	err = btc.ExportKeys(
 		extendedKey, strPaths, paths, chainParams, c.RecoveryWindow,
-		c.RescanFrom, exporter, os.Stdout,
+		c.RescanFrom, exporter, writer,
 	)
 	if err != nil {
 		return fmt.Errorf("error exporting keys: %v", err)

cmd/chantools/root.go

@@ -26,7 +26,7 @@ import (
 
 const (
 	defaultAPIURL = "https://blockstream.info/api"
-	version       = "0.9.2"
+	version       = "0.9.3"
 	na            = "n/a"
 
 	Commit = ""

doc/chantools_fakechanbackup.md

@@ -61,7 +61,7 @@ chantools fakechanbackup --from_channel_graph lncli_describegraph.json \
       --channelpoint string         funding transaction outpoint of the channel to rescue (<txid>:<txindex>) as it is displayed on 1ml.com
       --from_channel_graph string   the full LN channel graph in the JSON format that the 'lncli describegraph' returns
   -h, --help                        help for fakechanbackup
-      --multi_file string           the fake channel backup file to create (default "results/fake-2021-08-29-18-21-11.backup")
+      --multi_file string           the fake channel backup file to create (default "results/fake-2021-08-29-22-04-34.backup")
       --remote_node_addr string     the remote node connection information in the format pubkey@host:port
       --rootkey string              BIP32 HD root key of the wallet to use for encrypting the backup; leave empty to prompt for lnd 24 word aezeed
       --short_channel_id string     the short channel ID in the format <blockheight>x<transactionindex>x<outputindex>

doc/chantools_genimportscript.md

@@ -18,6 +18,8 @@ The following script formats are currently supported:
   spent that way as they are watch-only.
 * bitcoin-importwallet: Creates a text output that is compatible with
   bitcoind's importwallet command.
+* electrum: Creates a text output that contains one private key per line with
+  the address type as the prefix, the way Electrum expects them.
 
 ```
 chantools genimportscript [flags]
@@ -35,12 +37,13 @@ chantools genimportscript --format bitcoin-cli \
 ```
       --bip39                   read a classic BIP39 seed and passphrase from the terminal instead of asking for lnd seed format or providing the --rootkey flag
       --derivationpath string   use one specific derivation path; specify the first levels of the derivation path before any internal/external branch; Cannot be used in conjunction with --lndpaths
-      --format string           format of the generated import script; currently supported are: bitcoin-importwallet, bitcoin-cli and bitcoin-cli-watchonly (default "bitcoin-importwallet")
+      --format string           format of the generated import script; currently supported are: bitcoin-importwallet, bitcoin-cli, bitcoin-cli-watchonly and electrum (default "bitcoin-importwallet")
   -h, --help                    help for genimportscript
       --lndpaths                use all derivation paths that lnd used; results in a large number of results; cannot be used in conjunction with --derivationpath
       --recoverywindow uint32   number of keys to scan per internal/external branch; output will consist of double this amount of keys (default 2500)
       --rescanfrom uint32       block number to rescan from; will be set automatically from the wallet birthday if the lnd 24 word aezeed is entered (default 500000)
       --rootkey string          BIP32 HD root key of the wallet to use for decrypting the backup; leave empty to prompt for lnd 24 word aezeed
+      --stdout                  write generated import script to standard out instead of writing it to a file
 ```
 
 ### Options inherited from parent commands

lnd/hdkeychain.go

@@ -157,19 +157,9 @@ func AllDerivationPaths(params *chaincfg.Params) ([]string, [][]uint32, error) {
 		)
 	}
 	pathStrings := []string{
-		"m/44'/0'/0'",
-		"m/49'/0'/0'",
+		WalletBIP49DerivationPath,
 		WalletDefaultDerivationPath,
-		mkPath(keychain.KeyFamilyMultiSig),
-		mkPath(keychain.KeyFamilyRevocationBase),
-		mkPath(keychain.KeyFamilyHtlcBase),
 		mkPath(keychain.KeyFamilyPaymentBase),
-		mkPath(keychain.KeyFamilyDelayBase),
-		mkPath(keychain.KeyFamilyRevocationRoot),
-		mkPath(keychain.KeyFamilyNodeKey),
-		mkPath(keychain.KeyFamilyStaticBackup),
-		mkPath(keychain.KeyFamilyTowerSession),
-		mkPath(keychain.KeyFamilyTowerID),
 	}
 	paths := make([][]uint32, len(pathStrings))
 	for idx, path := range pathStrings {